The Motor Protection Consultants

Michael Flanagan National Marketing ManagerStandard Power Products(281) [email protected]

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A Guide to ApplyingAccording to NEC and ULMotor Circuit Controllers

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Direct Access MenuYou may jump directly to the desired section by selecting from the menu belowNEC 430-52Individual BCPDsNEC 430-152BCPD Selection TableNEC 240-6Next Size Larger BCPDNEC 430-53AGroups 1HP or lessNEC 430-53BSmall Motor GroupsNEC 430-53COther Group InstallationsNEC 430-52C6Type E Motor ControllersGroup ExamplesGroup BCPD SizingNEC 430-53DMotor Tap RulesApplication DataAdditional Reference MenuNEC 100Definitions

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Words in White Italics are taken directly from the NECWords in captions are interpretations of the NECIn the Following Slides

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In the Following Slides Click on this book to return to the Direct Access Menu

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NEC Article 100 - DefinitionsMBranch CircuitThe circuit conductors between the final short-circuit device (protecting the circuit) and the motor load.

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MDisconnectA device designed to apply main power or disconnect main power from a branch circuit. An At Motor must be within sight and within 50 feet of the motor to provide the maintenance electrician a degree of safety.

NEC Article 100 - Definitions

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BCPDNEC Article 100 - Definitions Fused Device orCircuit BreakerM Branch-Circuit short-circuit & ground-fault Protection Device

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Disconnect & BCPDA single device can incorporate the function of Disconnect and BCPD but this is NOT a code requirement.NEC Article 100 - Definitions Fused Device orCircuit BreakerM

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MControllerA device or group of devicesthat serves to govern,in some predetermined manner,the electric power deliveredto the connected load.

NEC Article 100 - Definitions

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NEC 430-52Selecting anIndividual Motor Circuit BCPD

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NEC 430-52Selecting an Individual Motor Circuit BCPD(a) General The motor branch-circuit short-circuit and ground-fault protection device shall comply with (b) and either (c) or (d), as applicable.(b) All Motors The motor branch-circuit short-circuit and ground-fault protection device shall be capable of carrying the starting current of the motor.(c )Rating or Setting (17) 1- A protective device having a rating or setting not exceeding the value calculated according to the value given in Table 430-52 shall be used.

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NEC 430-52Selecting an Individual Motor Circuit BCPDThe BCPD for a motor must be selected according to Table 430-52

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NEC Table 430-52Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices

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NEC 430-52 C.1Exception No. 1Where the values for branch-circuit short-circuit and ground-fault protective devices determined by Table 430-152 do not correspond to the standard sizes or ratings of fuses, nonadjustable circuit breakers, thermal protective devices, or possible settings of adjustable circuit breakers, any of which are adequate to carry the load, the next higher size, rating, or setting shall be permitted.,

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NEC 240-6Standard BCPD SizesThe next standard size BCPD is allowed if the calculation does not match a standard size per NEC 240-6.ContinueNEC 240-6

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NEC 240-6

Standard Ampere ratings:The standard ampere ratings for fuses and inverse time circuit breakers shall be considered 15, 20, 25, 30, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 400, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000.

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B.C.P.D. must be the next standard size larger than value calculated from Table 430-152.

NEC 240-6

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NEC 430-52Individual BCPDsMMMMExample: Four Starter Power Circuit

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NEC 430-52Individual BCPD May be one of the following:

A non-time delay fuse A time delay fuse An inverse-time circuit breaker (thermal-magnetic breaker) A magnetic-only circuit breaker (MCP or HMCP)

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NEC 430-52 CNEC 430-52 C contains seven options. Option #1 was to select the BCPD from the Table 430-52. Options 2-5 covers applications that do not normally apply to Motor Circuit Controllers which are explained by the reference below & summarized on the next slide.SummaryOption 2-5

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NEC 430-52 (C-Option 2-5)

The following slides are focused on NEC 430-52 C-Options 2-5 for your reference.

Continue

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NEC 430-52 (C-Option 2)Rating or Setting for Individual Motor Circuit

(c )Rating or Setting (17) continued 2- Where maximum branch-circuit short-circuit and ground-fault protection device ratings are shown in the manufacturer's overload relay table for use with a motor controller or are otherwise marked on the equipment, they shall not be exceeded even if higher values are allowed as shown above.

Some OLRs have a maximum ampere rating of the up-stream BCPD & this value should not be exceeded.

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(c )Rating or Setting (17) continued 3- An instantaneous trip circuit breaker shall be used only if adjustable and if part of a listed combination controller having coordinated motor overload and short-circuit and ground-fault protection in each conductor, and the setting is adjusted to no more than the value specified in Table 430-152.

MCPs should only be used as BCPDs in a UL Listed Combination starter.

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(c )Rating or Setting (17) continued 4- For a multi-speed motor, a single circuit and ground-fault protection device shall be permitted for two or more windings of the motor, provided the rating of the protective device does not exceed the above applicable percentage of the nameplate rating of the smallest winding protected.

BCPDs selected for multi-speed motors must protect the smallest HP winding.

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(c )Rating or Setting (17) continued 5- Suitable fuses shall be permitted in lieu of devices listed in Table 430-152 for power electronic devices in a solid state motor controller system provided that the marking for replacement fuses is provided adjacent to the fuses.

I2t Fuses can be used with a solid state drives and soft-starters if a label covering replacement is placed in the panel.

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C) OTHER GROUP INSTALLATIONS1- Select a BCPD from the Table 430-52 consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCPs should only be used as BCPDs in a UL Listed Combination starter4- BCPDs selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panel NEC 430-52 C Individual BCPD Option 1-76-7-

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NEC 430-52 (C-Option 6)Selecting an Individual Motor Circuit BCPDOption 6 is new to the 1999 NEC and the key is to understand what a Self-protected combination controller is and how this relates to UL 508 Type E approval.(Click reference button below for details)SummaryOption 6

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NEC 430-52 (C-Option 6)Selecting an Individual Motor Circuit BCPD

(c )Rating or Setting (17) continued 6- A listed self-protected combination controller shall be permitted in lieu of the devices specified in Table 430-52. Adjustable instantaneous-trip settings shall not exceed 1300 percent of full-load motor current for other than Design E motors or Design B energy efficient motor and not more than 1700 percent of full-load motor current for Design E motors or Design B energy efficient motors.

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NEC 430-109

The disconnecting means shall be a type specified in (a), unless permitted in (b) through (g), under the conditions specified.(a )General (1..6) 1- A listed motor-circuit switch rated in horsepower. For Design E motors rated greater than 2 HP, the motor circuit switch shall be either (a) marked as rated for use with Design E motors or (b) have a horsepower rating not less than 1.4 times the rating of a motor 3-100 HP, or not less than 1.3 times the rating of a motor rated over 100 HP.

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NEC 430-109

(a )General (1..6)2- A listed molded case circuit breaker3- A listed molded case switch.4- An instantaneous trip circuit breaker that is part of a listed combination motor controller.5- Listed self-protected combination controller.6- Listed manual motor controllers additionally marked Suitable as a Motor Disconnect shall be permitted as disconnecting means where installed between the final motor branch-circuit short-circuit and ground-fault protection device and the motor.

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UL508 Combination Construction Types

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UL 508

UL508 Seventeenth Edition (Dated January 28.1999) covering Industrial Control EquipmentPart III (Sections 72-75) Manual Motor ControllersPart IV Combination Motor Controllers

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UL 508 Part III Combination Motor Controller

Section 72 - 75Describes all of the construction requirements and applicable performance tests covering manual motor controllers. It is not necessary for our discussions to review all these standards except one.

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UL 508 Part IV Combination Motor Controller

Section 75.2A manual motor controller additionally intended for use as a motor disconnecting means shall be marked Suitable as Motor Disconnect.

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UL 508 Part IVCombination Motor Controller

76 GeneralThese requirements cover combination controllers which provide a disconnecting means and a load switching means within a device or assembly. In addition, overload and short-circuit protection may also be incorporated. The functions may be provided discrete components or be combined in a single controller.

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Table 76.2Various constructions of combination motor controller

Component Parts Construction Type A Disconnecting Means Manual Disconnect (UL 98 or UL 1087)

Short-circuit Fuse (UL 196)Protection Device

Motor ControllerMagnetic (UL 508)

Overload ProtectionOverload Relay (UL 508)

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Flange OperatedFusible Combo Starters

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Thru-the-door OperatedFusible Combo Starters

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Component Parts Construction Type B Disconnecting Means Manual Disconnect (UL 98 or UL 1087)

Short-circuit Motor Short-circuitProtection Device Protector (UL 508)



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Component Parts Construction Type C Disconnecting Means Circuit Breaker (UL 489)

Short-circuit Inverse Time TripProtection Device Circuit Breaker (UL 489)



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Flange OperatedCircuit Breaker Combo Starters

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Thru-the-door OperatedCircuit Breaker Combo Starters

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Component Parts Construction Type D Disconnecting Means Circuit Breaker (UL 489)

Short-circuit Instantaneous TripProtection Device Circuit Breaker (UL 489)



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Component Parts Construction Type E Disconnecting Means Self-protected Control Devices (UL 508)Short-circuitProtection Device

Motor Controller

Overload Protection

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Construction Type EMotor Circuit Controller

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Component Parts Construction Type F Disconnecting Means Self-protected Control Devices (UL 508)Short-circuitProtection Device

Motor Controller Magnetic (UL 508)

Overload Protection

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Construction Type FMotor Circuit Controller

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76.11 Self-protected control device A combination motor controller having non-replaceable components - integral discriminating overload and short-circuit current sensors - and provided with one or more sets of contacts where the contacts cannot be isolated for separate testing, is considered to be a Type E device as specified in Table 76.2.

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Table 76.2Various constructions of combination motor controllerConstruction Type Common Name

AFusible Comb Starter BShort-circuit Protector Combo Starter CThermal-magnetic CB Comb Starter DMCP CB Comb Starter ESelf-protected Combination Controller FSelf-protected Combination Controller + Magnetic Contactor

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Table 76.3Minimum required spacing for Type E combination controller at field wiring terminals on the line side Revised Table effective July 16, 2001

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Table 76.3 Minimum required spacing for Type E combination controller at field wiring terminals on the line side

This additional provision impacts Type E design effective July 16, 2001. This will require an additional line shield be added to the KT7 to achieve the 2 clearance specified. S+S will make this add-on shield available in the first half of 2001.

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UL 508 Part III & IV NEC 430-109

These sections of UL & NEC define a new kind of Combination Motor Controller. This Type E motor controller can be a manual starter but there is no requirement that the remote control function be part of the manual starter. If the magnetic contactor function is integral to the device then the integral device must meet the same Type E performance tests.

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Self-protected Combination Construction Type E

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(4) Functions of a Combination StarterNational Electric Code

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C) OTHER GROUP INSTALLATIONS1- Select a BCPD from the Table 430-152 consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCPs should only be used as BCPDs in a UL Listed Combination starter4- BCPDs selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panel6- UL Listed Type E Self-protected combination controller can be a BCPD NEC 430-52 C Individual BCPD Option 1-77-

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NEC 430-52 CNEC 430-52 C-Option #7 is also new in the 1999 NEC and covers a special application for motor circuit controllers which are explained by the reference below & summarized on the next slide.

SummaryOption 7

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(c )Rating or Setting (17) continued 7- A motor short-circuit protector shall be permitted in lieu of devices listed in Table 430-152 if the motor short-circuit protector is part of a listed combination motor controller having a coordinated motor overload protection and short-circuit and ground-fault protection in each conductor and it will open the circuit at current exceeding 1300 percent of motor full-load current for other than Design E motors or Design B energy efficient motors and 1700 percent of motor full-load current for Design E or Design B energy efficient motors.

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Option 7 allows a short-circuit only protector to be used as a BCPD if the assembly including the OLR is UL Listed as a combination.

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C) OTHER GROUP INSTALLATIONS

Option 7 is similar to using a magnetic-only circuit breaker (MCP) in addition to a classical starter consisting of a contactor and overload relay.

Option 6 offers the same opportunity except where the application requires an overload relay with features that exceeds those of the thermal trip mechanism in the motor circuit controller.


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NEC 430-52 (C-Option 7)KA7 + CA7 + CEP7 = 3 component starter

CLT7

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NEC 430-52 (C-Option 7)3- component starter

Those special overload features might include the following: Multiple motor starter panel requires individual resets Class 15, 20 or 30 protection Remote reset option Motor stall protection Ground Fault protection PTC therminstor relay function Communications

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C) OTHER GROUP INSTALLATIONS1- Select a BCPD from the Table 430-152 consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCPs should only be used as BCPDs in a UL Listed Combination starter4- BCPDs selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panel6- UL Listed Type E Self-protected combination controller can be a BCPD NEC 430-52 C Individual BCPD Option 1-77- A short-circuit only protector can be used as a BCPD if the assembly including the OLR is UL Listed as a combination

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Individual BCPDNEC 430-52 & the corresponding sections of UL508 provides for seven options in the use of a BCPD to protect an individual branch circuit and a single motor. There may be multiple BCPDs in a control panel.

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NEC 430-52 requires individual BCPDs to protect every motor circuit NEC 430-53 allows for a single BCPDto protect multiple motor circuitsin a group installation NEC 430-52 vs. NEC 430-53

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NEC 430-53Group Installation OutlineSeveral motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations

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NEC 430-53 ASeveral motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installationsSummary430-53A

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NEC 430-53 A

Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations

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NEC 430-53 ANot Over 1HP

Several motors each not exceeding 1 Horsepower in rating shallbe permitted on a nominal 120 Volt branch circuit protected at not over 20 Amperes or of 600 Volts, nominal, or less, protected at notover 15 Amperes, if all of the following conditions are met:

1) The full-load rating of each motor does not exceed 6 Amperes.2) The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is not exceeded.

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A single BCPD not exceeding 20 Amps for 120 Volt 1-phase or 15 Amps for any circuit 208-575 Volt (1-phase or 3-phase) may protect multiple motors if:

(1)1800 RPM motors have an FLA < 6 Amps. (2)The BCPD rating does not exceed the maximum rating shown on the overload relay label.

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Several motors each not exceeding 1 Horsepower in rating shallbe permitted on a nominal 120 volt branch circuit protected at not over 20 amperes or of 600 volts, nominal, or less, protected at notover 15 amperes, if all of the following conditions are met:

1) The full-load rating of each motor does not exceed 6 Amperes.

2) The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is not exceeded.

3) Individual overload protection conforms to section 430-32.

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NEC 430-32Overload Selection

Continue

NEC430-32

NEC 430-32 explains the conditions at which an overload relay must trip. A summary of this section of the code is shown on the next slide or click on the button below to get the full details.

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NEC 430-32Continuous Duty Motors

Each continuous-duty motor rated more than 1 horsepower shall be protected by one of the following means:(1)A separate overload device that is responsive to motor current. This device shall be selected to trip or rated at no more than the following percent of the motor nameplate full-load current rating:Motors with a marked service factor not less than 1.15...................125% Motors with a marked temperature rise not over 40 C. ................125%All other motors ...............................................................................115%Modification of this value shall be permitted as provided in Section 430-34.For a multi-speed motor, each winding connection shall be considered separately. Continued............

(a) More than 1 Horsepower

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(a) Motors over 1 HP must be protected by: (1) A overload that trips at : 1.15 Service Factor Motors - 125% FLA 1.00 Service Factor Motors - 115% FLA - 430-34 is an exception to the above settings - For multi-speed motors each overload is selected and set according to the FLA of each winding.

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NEC 430-32 (a) (1)Continuous Duty Motors

Continued......

Where a separate motor overload device is so connected that it does not carry the total current designed on the motor nameplate, such as for wye-delta starting, the proper percentage of nameplate current applying to the selection or setting of the overload device shall be clearly designated on the equipment, or the manufacturers selection table shall take this into account.

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(a) Motors over 1 HP must be protected by: (1) A overload that trips at : 1.15 Service Factor Motors - 125% FLA 1.00 Service Factor Motors - 115% FLA - 430-34 is an exception to the above settings - For multi-speed motors each overload is selected and set according to the FLA of each winding. - Wye-delta overload should be set for the portion of total motor FLA it carries

(normally 58%).

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NEC 430-32 (b)One Horsepower or Less, Non-automatically Started

(1) Each continuous-duty motor rated at 1 horsepower or less that is not permanently installed, is non-automatically started, and is within sight from the controller location shall be permitted to be protected against overload by the branch-circuit short-circuit and ground-fault protection device. This branch-circuit protective device shall not be larger than specified in Part D of Article 430.Exception: Any such motor shall be permitted on a nominal 120-volt branch circuit protected at not over 20 amperes.(2) Any such motor that is not in sight from the controller location shall be protected as specified in Section 430-32(c). Any motor rated at 1 horsepower or less that is permanently installed shall be protected in accordance with Section 430-32(c).

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NEC 430-32 (b)One Horsepower or Less, Non-automatically Started

(b)(1) This Section of the code refers to motors that are temporally installed which can be protected simply by a B.C.P.D. without an overload.

Note:Our focus is on multi-starter control panels designed for permanent (continuos duty).

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NEC 430-32 (c)Continuous Duty Motors

Any motor of 1 horsepower or less that is stated automatically shall be protected against overload by one of the following means:(1)A separate overload device that is responsive to motor current. This device shall be selected to trip or rated at no more than the following percent of the motor nameplate full-load current rating:Motors with a marked service factor not less than 1.15 .............125% Motors with a marked temperature rise not over 40 C.............125%All other motors ..........................................................................115%For a multi-speed motor, each winding connection shall be considered separate. Modification of this value shall be permitted as provided in Section 430-34.

(c) One Horsepower or less, Automatically Started

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NEC 430-32 (c)Continuous Duty Motors

(c) Motors 1 HP or less must be protected by: (1) A overload that trips at : 1.15 Service Factor Motors - 125% FLA 1.00 Service Factor Motors - 115% FLA - For multi-speed motors each overload is selected and set according to the FLA of each winding. - 430-34 is an exception to the above settings

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NEC 430-34Selection of Overload Relay

Where the overload relay selected in accordance with Section 430-32(a)(1) and (c)(1) is not sufficient to start the motor or to carry the load, the next higher size overload relay shall be permitted to be used, provided the trip current of the overload relay does not exceed the following percentage of motor full-load current rating.Motor with marked service factor not less than 1.15 ..... 140% Motor with a marked temperature rise of over 40 C. .... 140%All other motors ................................................................ 130% If not shunted during the starting period of the motor as provided in Section 430-35, the overload device shall sufficient time delay to permit the motor to start and accelerate its load.

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NEC 430-34Selection of Overload Relay

Motors that have an inrush greater than normal (6 X FLA) or long acceleration time and will not start and/or run under 430-32; then overload selection and setting may be increased to the following:1.15 Service Factor Motors - 140% FLA 1.00 Service Factor Motors - 130% FLA An alternate exception to this section is described in 430-35 which allows by-passing the overload during start-up (often referred to as a heavy-duty start circuit).

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A Summary of NEC 430-32

(a) Motors > 1 HP must be protected by an overload that trips at : 1.15 S.F. Motors - 125% FLA 1.00 S.F. Motors - 115% FLA(b) Refers to motors that are temporally installed and protected simply by a B.C.P.D. without an overload.(C) Motors < 1 HP must be protected by an overload that trips at : 1.15 S.F. Motors - 125% FLA 1.00 S.F. Motors - 115% FLA

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A Summary of NEC 430-32

(a) Motors > 1 HP must be protected by an overload that trips at : 1.15 S.F. Motors - 125% FLA 1.00 S.F. Motors - 115% FLA(b) Refers to motors that are temporally installed and protected simply by a B.C.P.D. without an overload.(C) Motors < 1 HP must be protected by an overload that trips at : 1.15 S.F. Motors - 125% FLA 1.00 S.F. Motors - 115% FLA

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(1) 1800 RPM motors have an FLA < 6 Amps.

(2) The BCPD rating does not exceed the maximum rating shown on the overload relay label.

(3) UL approved overload relays comply with 430-32.

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(1) 1800 RPM motors have an FLA < 6 Amps.

(2) The BCPD rating does not exceed the maximum rating shown on the overload relay label.

(3) UL approved overload relays comply with 430-32.


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NEC 430-53 AMMMMGroup BCPD120V, 20A Max.3-Phase V, 15A Max.Individual BCPDsare NOT requiredContactorBCPD rating may not be exceededMotors1HP, 6 FLA Max. each

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NEC 430-53 BSeveral motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installationsSummary430-53B

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NEC 430-53 B


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If the branch-circuit short-circuit and ground-fault protective device is selected, not to exceed that allowed by section 430-52 for the motor of the smallest rating, then

NEC 430-53 B If the Smallest Motor Protected

two or more motors or one or more motors and other load(s), with each motor having individual overload protection,

shall be permitted to be connected to a branch circuit where it can be determined that

the branch-circuit short-circuit and ground-fault protective device will not open under the most severe nominal conditions of service that might be encountered.

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A single BCPD may protect multiple motors and other loads if all the following conditions are met:


(1)BCPD shall not exceed that allowed by 430-152 to protect the smallest motor.

(2)BCPD will not open under the inrush current of starting and will carry the combined FLA of motors and/or other load(s).

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Example #1:Dual ElementHP @ 460V FLA Fuses 5 7.6 15 A 10 14 25 A __________ Group 21.6 15 A


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Example #2:Dual ElementHP @ 460V FLA Fuses 5 7.6 15 A 5 7.6 15 A _________ Group 15.2 15 A


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Example #3:Dual ElementHP @ 460 V. FLA Fuses 2 3.4 15 A 3 4.8 15 A __________ Group 8.2 15 A


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A single BCPD may protect multiple motors and other loads if all the following conditions are met:NEC 430-53 B If the Smallest Motor Protected(1)BCPD shall not exceed that allowed by 430-152 to protect the smallest motor.(2)BCPD will not open under the inrush current of starting and will carry the combined FLA of motors and/or other load(s).

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3HP2HPIndividual BCPDsare NOT requiredGroup BCPD15A Max.Example #3:NEC 430-53 B If the Smallest Motor Protected

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Several motors or loads on 1 branch circuitNEC 430-53 A or B A)Group fusing is widely used under this provision.or B)This provision is limited to 2 or 3 motors < 5 HP and simultaneous starting may not be allowable.

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Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installationsNEC 430-53 CSummary430-53C

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NEC 430-53 C


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NEC 430-53 C (1) Other Group Installations

Two or more motors of any rating or one or more motors and other load(s), with each motor having individual overload protection, shall be permitted to be connected to one branch circuit where the motor controller(s) and overload devices(s) are:

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NEC 430-53 C (1)

M

M

M

M

Group BCPD

Individual BCPDsare NOT required

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A single BCPD may protect multiple motor circuits if an overload is provided for each motor circuit and

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(1)Installed as a listed factory assembly and the motor branch-circuit short-circuit and ground-fault protective device is either provided as a part of the assembly or


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(1)The BCPD is provided as a part of the factoryassembled control panel


Note: A factory assembly in this context means a single control panel assembled in a control panel shop.

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M

M

M

M

BCPD provided as part of the assembly


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NEC 430-53 C (1 or 2) Other Group Installations

(1) Factory assembled multistarter panel - with the BCPD installed

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(1)Installed as a listed factory assembly and the motor branch-circuit short-circuit and ground-fault protective device is either provided as a part of the assembly or specified by a marking on the assembly.


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(1) The BCPD is provided as a part of the factory assembled control panel or the BCPD is specified by a label on the control panel

Note: A factory assembly in this context means a single control panel assembled in a control panel shop.


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M

BCPDSafety SwitchorPanelboardCircuit Breaker

M

M

M

BCPD Outside of the Assembly


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Suggested Label

This control panel must be fed by one of the following short-circuit devices:(1)Non-time delay fuses Amps max.(2)Time delay fuse Amps maximum (3)Inverse-time circuit breaker Amps maximum

BCPD Outside of the Control Panel


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(1) Factory assembled multistarter panel - With the BCPD installed or - Separate BCPD & labeled panel

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NEC 430-53 C (1 or 2)

(2) The motor branch-circuit short-circuit and ground-fault protective device, the motor controller and overload device are field installed as separate assemblies listed for such use and provided with manufacturers instructions for use with each other.

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NEC 430-53 C ( 2)

(2)The BCPD (safety switch or panel board breaker) and starters are wall mounted in separate enclosures connected with wire in conduit.

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NEC 430-53 C (2)

Separate Assemblies

M

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(1) Factory assembled multistarter panel - With the BCPD installed or - Separate BCPD and labeled panelor (2) Field installed separate assemblies

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(3)All of the following conditions are complied with:

(1)Each motor overload device is listed for group installation with a specified rating of fuse or inverse time circuit breaker or both.

NEC 430-53 C (1 or 2 and 3) Other Group Installations

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NEC 430-53 C (3.1)

Standard overload relays are not group rated.

Group rated overload relays have short-circuit capabilities

The label for a group rated overload relay must show the maximum amp rating of the up-stream BCPD

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(1) Factory assembled multistarter panel - with the BCPD installed or - separate BCPD and labeled panelor (2) Field installed as assembliesand (3) All of the following conditions are met: 1-Overload relay must be group rated 2- 3- 4- 5-


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(2)Each motor controller is listed for group installation with a specified maximum rating of fuse or inverse circuit breaker, or both.



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NEC 430-53 C (3.2)

Group rated overload relays are also manual starters

A manual starter by definition controls the circuit in a predetermined manner and is therefore the motor controller Since group rated overload relays are the motor controllers then 3.2 makes the same provision as 3.1 concerning maximum rating of the up-stream BCPD

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(1) Factory assembled multistarter panel - with the BCPD installed or - separate BCPD & labeled panelor (2) Field installed separate assembliesand(3) All of the following conditions are met: 1-Overload relay must be group rated 2-Controller must be group rated 3- 4- 5-


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(2)Each motor controller is listed for group installation with a specified maximum rating of fuse or inverse circuit breaker, or both.

(3)Each circuit breaker is one of the inverse time type and listed for group installation.



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NEC 430-53 C (3.3)

NEC Table 430-152 allows individual BCPDs to be inverse-time circuit breakers (thermal-magnetic breakers) or magnetic-only circuit breakers (MCP) or fuses.

NEC 430 C (3.3) does not allow MCPs as group BCPDs

Group BCPDs may be fuses but if a breaker is used it must be an inverse-time type (thermal-magnetic breaker)

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(1) Factory assembled multistarter panel - with the BCPD installed or - separate BCPD and labeled panelor (2) Field installed separate assembliesand(3) All of the following conditions are met: 1-Overload relay must be group rated 2-Controller must be group rated 3-Circuit breakers must be thermal- magnetic type 4- 5-


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NEC 430-53 C (3.4)

(3.4) The branch circuit shall be protected by fuse or inverse time circuit breakers having a rating not exceeding that specified in section 430-52 for the largest motor connected to the branch circuit

plus an amount equal to the sum of the full-load current ratings of all other motors and the ratings of other loads connected to the circuit

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NEC 430-53 C (3.4)

(3.4) The BCPD must be sized by the table 430-152 for the largest motor FLA + sum of all other FLAs.Loads other than motors may consist of control power transformer or space heaters or solenoids, etc. ...

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NEC 430-53 C (3.4)

(3.4) The branch circuit shall be protected by fuse or inverse time circuit breakers having a rating not exceeding that specified in section 430-52 for the largest motor connected to the branch circuit plus an amount equal to the sum of the full-load current ratings of all other motors and the ratings of other loads connected to the circuit where this calculation results in a rating less thanthe ampacity of the supply conductors, it shall be permitted to increase the maximum rating of the fuses or circuit breaker to a value not exceeding that permitted by section 240-3(b).

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NEC 430-53 C (3.4)

Note:Our primary focus is on designing a new control panel which means that the supply conductors would be properly sized after the ampacity requirement has been determined. It seems that this portion of NEC 430-53C (3.4) would apply only in a retrofit situation.

NEC 240-3

Reference Information

Continue

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NEC 240-3(b)

Devices Rated 800 Amperes or Less.

Conductors not part of a multi-outlet branch circuit supplying receptacles for cord-and plug-connected portable loads and where the ampacity of the conductors does not correspond with the standard ampere rating of a fuse or a circuit breakerwithout overload trip adjustments above its rating (but not have other trip or rating adjustments), the next higher standard device rating does not exceed 800 amperes.

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NEC 240-3(b)

This section of the NEC simply says if your calculation results in a non-standard rating less 800 amperes then you may go up to the next standard size fuse or circuit breaker.

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10 HP13.4 FLA

5 HP7.2 FLA

3 HP4.7 FLA

1 HP1.8 FLA

NEC 430-53 C (3.4)

SIZING a multistarter time-delay fused BCPD

Largest FLA x 1.75 + (sum of other loads) = max. time delay fuse(13.4 x 1.75)+7.2+4.7+1.8 = 37.2 = 40 amp max. BCPD

M

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M

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NEC 430-53 C

C) Other Group Installations

(1) Factory assembled multi-starter panel - with the B.C.P.D. Installed or - separate B.C.P.D. and labeled panelor (2) Field installed separate assembliesand(3) All of the following conditions are met: 1-OLR must be group rated 2-Controller must be group rated 3-Circuit breakers must be thermal-magnetic type 4-BCPD must be sized properly 5-

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NEC 430-53 C (3.5)NEC 430-40 Reference

(3.5)The branch-circuit fuses or inverse time circuit breakers are not larger than allowed by Section 430-40 for the overload relay protecting the smallest rated motor of the group.

NEC430-40

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NEC 430-40 Overload Relays

Overload relays and other devices for motor overload protection that are not capable of opening short circuits shall be protected by fuses or circuit breakers with ratings or settings in accordance with Section 430-52 or by a motor short-circuit protector in accordance with Section 430-52.

Exception No. 1:Where approved for group installation and marked to indicate the maximum size of fuse or inverse time circuit breaker by which they must be protected.

Exception No. 2:The fuse or circuit breaker ampere rating shall be permitted to be marked on the nameplate of approved equipment in which the overload relay is used.

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NEC 430-40 Overload Relays

Standard Overload Relays must be protected by Individual B.C.P.D.s (same as NEC 430-52 & selection by Table (430-152).

Exception No. 1: Group Rated Overload Relays must be protected by B.C.P.D.s not exceeding the maximum rating shown on the label of the OLR (same as NEC 430-53C 3.1).

Exception No. 2: The B.C.P.D. may be located outside the control panel if a label is provided. (same as NEC 430 C (1 or 2).

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NEC 430-53 C (3.5)NEC 110-10 Reference

(3.5)The branch-circuit fuses or inverse time circuit breakers are not larger than allowed by Section 430-40 for the overload relay protecting the smallest rated motor of the group.

(FPN): See Section 110-10 for circuit impedance and other characteristics.

NEC 110-10

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The overcurrent protective devices, the total impedance, the component short-circuit withstand ratings, and other characteristics of the circuit to be protected shall be so selected and coordinated as to permit the circuit protective devices that are used to clear a fault without the occurrence of extensive damage to the electrical components of the circuit.

This fault shall be assumed to be either between two or more of the circuit conductors, or between any circuit conductor and the grounding conductor or enclosing metal raceway.

NEC 110-10

Circuit Impedance and other Characteristics.

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NEC 110-10

-Group Rated Overload Relays are by design current limiting devices and have a current withstand rating exceeding that of standard overload relays.

-Let-thru current of the B.C.P.D. must not exceed the current withstand rating (KAIC) for any of the group rated overload relays used within a group.

-This means that the selection of the B.C.P.D. should include consideration of the available fault current on the line side of the the B.C.P.D. and the let-thru current of the B.C.P.D.

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B.C.P.D. Coordination

-Commonly used RK5 dual-element branch-rated fuses do limit peak let-thru current and fuse curves should be consulted for group applications to insure coordination.

-RK5 fuses will protect at low levels of FLA & KAIC but as the size of the B.C.P.D. increases so does the peak let-thru current available to the overload relays.

-RK1 and J fuses significantly reduce peak let-thru current and are therefore recommended for use as B.C.P.D.s in larger amperage group applications (I.E.: > 200 Amps).

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(3.5) The BCPD may be a fuse or an inverse-timecircuit breaker but must be sized not to exceed the maximum rating on any of the group rated overload relays within the group.

NEC 430-53 C (3.5)

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NEC 430-53 C A Summary


(1) Factory assembled multi-starter panel - with the BCPD installed or - separate BCPD and labeled panelor (2) Field installed separate assembliesand(3) All of the following conditions are met: 1- OLR must be group rated 2- Controller must be group rated 3- Circuit breakers must be thermal-magnetic type 4- BCPD must be sized properly 5- KAIC rating should be coordinated

C) Other Group Installations

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C) OTHER GROUP INSTALLATIONS (1) Factory assembled multi-starter panel - with the BCPD installed or - separate BCPD and labeled panelor (2) Field installed separate assembliesand(3) All of the following conditions are met: 1- OLR must be group rated 2- Controller must be group rated 3- Circuit breakers must be thermal-magnetic type 4- BCPD must be sized properly 5- KAIC rating should be coordinatedNEC 430-53 C A SummaryC) Other Group Installations

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NEC 430-53 CExamplesA few examples might help to clarify the selection process for a Group Installation B.C.P.D.Continue

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Calculating minimumB.C.P.D.

HPFLA1014.0 711.0 5 7.6 1 1.8 1.035.4 TFLA x 1.2544.3 ~ 45 AMinimum B.C.P.D.

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Calculating maximumFused B.C.P.D.

HP10 14.0 x 1.75 = 24.5 7 11.0 5 7.6 1 1.8 1.0 45.9 ~ 50 A Fuse 60 A Block Maximum B.C.P.D.

Panel #1

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HPFLA1014.0 1014.0 5 7.6 1 1.8 1.038.4 TFLA x 1.2548.0 ~ 50 AMinimum B.C.P.D.

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HP10 14.0 x 1.75 = 24.510 14.0 5 7.6 1 1.8 1.0 48.9 ~ 50 A Fuse 60 A Block Maximum B.C.P.D.

Panel #2

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HPFLA1521.01014.0 1014.0 5 7.6 1 1.858.4 TFLA x 1.2573.0 ~ 80 AMinimum B.C.P.D.

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HP15 21.0 x 1.75 = 36.810 14.010 14.0 5 7.6 1 1.8 74.2 ~ 80 A Fuse 100 A Block Maximum B.C.P.D.

Panel #3

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This section of the NEC has caused some controversydue to its vagueness. The reference button below will support our interpretation. NEC 430-53 D Single Motor TapsNEC 430-53DSummary

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The 2002 NEC revised Section 430-53D covering Single Motor Taps which impacts the application of motor circuit controllers in a multi-motor starter control panel under Group Installation rules NEC 430-53.

NEC 430-53 D Single Motor Taps

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For group installations described above, the conductors of any tap supplying a single motor shall not be required to have an individual branch-circuit and group-fault protective device, provided they comply with one of the following:

NEC 430-53 D Single Motor Taps

(1)No conductor to the motor shall have an ampacity less than that of the branch-circuit conductors,

or (2) No conductor to the motor shall have an ampacity less than one-third that of the branch-circuit conductor, with a minimum in accordance with section 430-22; the conductors to the motor overload device being not more than 25 feet (7.62m) long and being protected from physical damage.

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NEC 430-53 D Clarification

NEC 430-53D part 1 requires tap conductor ampacity to be equal to the wire connected to the single B.P.C.D. of the group.or

NEC 430-53D part 2 requires tap conductor ampacity to be not less than 1/3 of the ampacity of the wire connected to the single B.P.C.D. of the group.

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It has been the position of many in the industry that NEC 430-53D was never intended to apply to multiple motor starter control panels per NEC 430-53C 1 & 3, but rather to separately mounted units with wire duct and gutter taps

NEC 430-53 D part 1 or 2 Single Motor Taps

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NEC 430-53 D

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M

The rating of the green wire should not be less than one third the rating of the red wire.

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The 2002 NEC introduced a new provisions for Single Motor Taps under Section 430-53D part 3, which clarifies the sizing motor circuit controller wires in a multi-motor starter control panel

NEC 430-53 D part 3 Single Motor Taps

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(3)Conductors from the branch-circuit short-circuit and ground-fault protection to a listed manual motor controller additionally marked Suitable for Tap Conductor Protection in Group Installations shall be permitted to have an ampacity not less than 1/10 the rating or setting of the branch-circuit short-circuit and ground-fault protection device.

1- be suitably protected from physical damage and enclosed either by an enclosed controller or by a raceway and shall not be more than 10 ft. long or2- shall have an ampacity not less than that of the branch circuit conductors

The conductors from the controller to the motor shall have an ampacity in accordance with 430-22. The conductors from the branch-circuit short-circuit and ground-fault protection to the controller shall be

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NEC 430-53 D part 3

This new provisions clearly defines the sizing of motor circuit controller wires at 1/10 that of the B.P.C.D. if the length does not exceed 10 feet.

This means most 25 ampere frame motor circuit controller that only allows for #10 wire maximum might be as large as 400 amperes.

This change in the 2002 NEC does require some additional testing of the motor circuit controller under UL508 in order to mark the device Suitable for Tap Conductor Protection in a Group Installation.

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The testing associated with single motor taps is nearly as difficult as those associated with the test for Self-protected Combination Motor Controllers. This means that the Tap Conductor Protection ratings may well align with the ratings for Self-protected Combination Motor Controllers.


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NEC 430-53 D Select for Additional Information

Continue

NEC 240-21

NEC 430-28

NEC 230-22

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NEC 240-21

The new section 430-53D part 3 is derived from NEC 240-21 which describes feeder tap circuits in section (b) & (c).

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NEC 240-21

Ungrounded Conductors Location in Circuit. An overcorrect device shall be connected in each ungrounded circuit conductor as follows:

(a) Feeder and Branch-Circuit Conductors.Feeder and branch-circuit conductors shall be protected by overcurrent-protective devices connected at the point the conductors receive their supply, unless otherwise permitted in (b) through (m) :

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NEC 240-21 (b)

(b) Feeder Taps not over 10 Feet (3.05 m) Long.

Conductors shall be permitted to be tapped, without overcurrent protection at the tap, to a feeder or transformer secondary where all the following conditions are met: (1) The length of the tap conductors does not exceed 10 feet (3.05 m). (2) The ampacity of the tap conductors are:a. Not less than the combined computed loads on the circuits supplied by the tap conductors, andb. Not less than the rating of the device supplied by the tap conductors, or not less than the rating of the overcurrent-protective device at the termination of the tap conductors. (3) The tap conductors do not extend beyond the switchboard, panelboard, or control devices they supply.

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(a) Feeder conductors may be tapped if one the following conditions of b through m are met:(b) Taps not over 10 feet must meet all of the following:(1) Taps do not exceed 10 feet.(2) Tap wire is as least as large as the connected load on each tap circuit and protected by an overload equally sized to protect the connected load.(3) Tap conductors must terminate in an overload within the the control panel.

NEC 240-21

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(b) Feeder Taps not over 10 Feet (3.05 m) Long. Continued ....

(4) Except at the point of connection to the feeder, the tap conductors are enclosed in a raceway, which shall extend from the tap to the enclosure of an enclosed switchboard, panelboard, or control devices or to the back of an open switchboard.

(5) For field installations where the tap conductors leave the enclosure or vault in which the tap is made, the rating of the overcurrent device on the line side of the tap conductors shall not exceed 1000 percent of the tap conductors ampacity.

NEC 240-21 (b)

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(a) Feeder conductors may be tapped if one the following conditions of b through m are met:(b) Taps not over 10 feet must meet all of the following: (1) Taps do not exceed 10 feet.(2) Tap wire is as least as large as the connected load on each tap circuit and protected by an overload equally sized to protect the connected load. (3) Tap conductors must terminate in an overload within the the control panel. (4) The tap connection and conductors must be enclosed by the control panel.(5) Tap conductors that leave the control panel must not be less than 1/10 of the B.C.P.D. feeder ampacity.

NEC 240-21

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NEC 240-21

NEC 240-21 (b) (1 & 2) Allow for multiple conductors to be tapped from a single branch-circuit if the conductor is sized to carry the sameampacity as the group rated overload it feedsas long as the conductor is not more that 10 feetlong and does not leave the multi-starter motorcontrol panel as outlined in (b) (3 & 4).

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Fully understanding the reference to Tap Circuits in NEC 430-53D requires examination of the definition of Tap Circuits as explained in NEC 430-28.

Lets take a look at 430-28

NEC 430-53D and NEC 430-28

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NEC 430-28

Feeder Taps.

Feeder tap conductors shall have an ampacity not less than required by Part B, shall terminate in a branch-circuit protective device and, in addition, shall meet one of the following requirements:

(1) be enclosed by either an enclosed controller or by a raceway, be not more than 10 feet (3.05 m) in length, and for field installation, be protected by overcurrent device on the line side of the tap conductor, the rating or setting of which shall not exceed 1000 percent of the tap conductor ampacity;

or (2) have an ampacity of at least one-third that of the feeder conductors, be protected from physical damage and be not more than 25 feet (7.62 m) in length;

or (3) have the same ampacity as the feeder conductors.

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Tap circuits protected by a single B.C.P.D. must meet one of the following conditions:

(1) be enclosed as in a control panel, be not more than 10 feet long, and the tap wire can not be less than 1/10 of the ampacity of the wire feeding to the B.C.P.D.

or (2) the tap wire can not be less than 1/3 of the ampacity of the wire feeding the B.C.P.D.

or (3) The tap wire is the same ampacity as the wire feeding the B.C.P.D.

NEC 430-28 Feeder Taps

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Clearly, meeting option (1) offers the most flexibility in designing a multi-motor starter control panel..

NEC 430-28 Feeder Taps

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NEC 230-22

Section 430-22 defines the minimum wire size of the conductors of single motor branch circuit.

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NEC 230-22

Single motor Taps (A) General.Branch circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125% of the motors full load current rating as determined by 430-6(A)(1).

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The general provisions under (A) simply states that branch conductor wires must be at least 125% of the connected load.

NEC 430-22 does not define the maximum conductor size or sizing tap conductors of a multi-motor starter panels. We must research other sections of the NEC to make this determination.

NEC 230-22

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NEC 430-53 D Clarification

NEC 430-28 defines that BCPD feeder conductors can be as large as 10 times tap circuit conductors.

NEC 240-21 also defines the 10-foot tap rule for control panels which allows taps at 1/10 the B.C.P.D.

NEC 430-22 defines that branch circuit conductors must be at least 125% of the FLA connected.

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NEC 430-53 D part 3This new provisions clearly defines the sizing of motor circuit controller wires at 1/10 that of the B.P.C.D. if the length does not exceed 10 feet. This means most 25 ampere frame motor circuit controller that only allows for #10 wire maximum might be as large as 400 amperes.This change in the 2002 NEC does require some additional testing of the motor circuit controller under UL508 in order to mark the device Suitable for Tap Conductor Protection in a Group Installation.

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It is our opinion that the strict enforcement of the wire sizing options defined by NEC 430-53D-1, -2, or -3 will force the industry to apply Self-protected Combination Motor Controllers (Construction Type E or Type F) in multiple motor starter panels under the provisions of NEC 430-52-C- 6 as opposed to applying simple Group Rated Manual Motor Circuit Controllers under Group Installations as defined under NEC 430-53-C. NEC 430-53 D part 3 Single Motor Taps

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Application of Mini-CBsMini-CBsThere are a lot of products with over lapping approvals and in many cases confusion about applicable standards resulting in mis-application of the products and non-compliance with UL and NEC requirements.A salesman told me we could use Mini-CBs and save money!?Continue

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Supplementary Overcurrent Protection.

Where supplementary overcurrent protection is used for lighting fixtures, appliances, and other equipment or for internal circuits and components of equipment,it shall not be used as a substitute for branch-circuit overcurrent devices or in place of the branch-circuit protection specified in Article 210. Supplementary overcurrent devices shall not be required to be readily accessible.

NEC 240-10

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UL 1077 Supplemental Protectors

Devices that protect appliances or electrical equipment loads from overloads and short-circuitsNot Substitutes for Branch Circuit ProtectionUsed to supplement Branch Circuit Protection

Supplemental Protectors have many different sizes, current ranges, and ratings depending on the industry and application

Appliance Type Supplementary

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Industrial DIN Rail MountUL 1077 Mini-CBs

UL 1077 approved as Supplementary Protectors for use in the control circuit of industrial control panelsAlso meets CSA 22.2 No. 235 Supplementary StandardAlso compliant with IEC 60898 for use in global installations where IEC standards are applicable.

UL-1077 Supplementary Protector

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UL 1077 Mini-CBs

Mini-Circuit Breakers tested under UL 1077 and UR approved for Supplemental Protection may be applied in appliances, business Equipment, or control circuits of industrial control panels in addition to the overload relays and branch-circuit short-circuit protection both which are required by the NEC.

This means that UL 1077 Mini-Circuit Breakers may not be used in place of UL 489 circuit breaker applied as a B.C.P.D.'s under NEC 430-52 or NEC 430-53 and may not be used in place of UL508 overload relays under NEC 430-32.

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Applications:B-Curve Characteristics

In General:Primarily to protect conductors. Instantaneous trip is three to five times the rated current of the MCB (3~5xIn). Fast trip times minimize damage to control circuit conductors from low-level faults.

Per UL, NEC and IECLightingConductor ProtectionControl Circuits and CoilsComputersAppliancesGeneral ElectronicsPLC Outputs

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Applications:C-Curve Characteristics

In General:Primarily for applications with moderate inrush currents. Instantaneous trip is five to ten times the rated current of the MCB (5~10xIn). Higher instantaneous trip level prevents nuisance tripping.Components being protected can typically withstand higher fault currents without being damaged.

Per UL, NEC and IECLightingConductor ProtectionControl Circuits and CoilsComputersAppliancesGeneral Electronics Per IECMotors with inrush currents of 6~10 times FLC and associated controllers.

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Applications:D-Curve Characteristics

In General:Primarily for applications with high inrush currents. Instantaneous trip is ten to twenty times the rated current of the MCB (10~20xIn). High instantaneous trip level prevents nuisance tripping.Components being protected can typically withstand higher fault currents without being damaged.

Per UL, NEC and IECTransformersPower SuppliesHeatersPer IECMotors with inrush currents of 6~10 times FLC and associated controllers.

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Applying UL 1077 Mini-CBs

Per UL 508A Industrial Control Panels, Supplemental Devices May Protect:

Control circuit components such as relay coils, starter coils, timers and remote solenoidsetc.

Sensitive internal circuitry such as: Electronic Controllers Communication Equipment Power Supplies Computers and Microprocessors

Control Transformers (Primary & Secondary)

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Applying UL 1077 Per UL-508A

Typical Motor Control Circuit

Main BCPDUL489/CSA 5.1

Fuse - BCPDUL512/CSA C22.2

Motor StarterContact+Overload

Incoming 3-Phase

BCPDCB or Fuse

Motor

Power Transformer

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UL 508A Compliance

UL 1077 Mini-Circuit Breakers may NOT be applied in: Protection of Power Transformer (Primary/Secondary) Protection of Motor Loads Protection of Heater Loads Protection of Lamp Loads

UL 1077 Mini-Circuit Breakers may NOT be applied as: Branch-circuit short-circuit protection device Overload relay

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Additional Types of Mini-CBs

Different UL Standards & Applications

UL-1077 Supplementary ProtectionUL-508 Manual Motor ControllersUL-489 Branch Circuit Protection

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UL 508 ListedManual Motor Controllers

UL 508 Manual Motor ControllersA Listed Manual Motor Controller, additionally marked Suitable as Motor Disconnect, shall be permitted as a disconnecting means where installed between the final motor branch-circuit short-circuit and ground-fault protective device and the motor.The CSA C22.2 No. 14 Standard is equivalent to the UL-508 Standard

Altech V-EA SeriesUL-508 Device

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UL 508 Manual Motor Starter

Mini-Circuit Breakers approved as Manual Motor Starter under UL 508 may used as a Controller under 430-(81-91) and an overload relay under NEC 430-32 and might additionally be approved as Disconnecting Means under 430-109(a) (6)

Mini-Circuit Breakers approved as Manual Motor Starter under UL 508 may NOT be used as a B.C.P.D., branch-circuit short-circuit protection device.

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Applying A UL-508 ManualMotor Controllers Per UL-508A



Incoming 3-Phase

BCPDCB or Fuse

Motor

Power Transformer

UL-508 M-CBOr MCB could be upstream from the Motor Starter

Control Circuit

SP Supplemental Protectors

UL-508 Permitted for Use:Replaces the Motor Starter and the Fuse Protection (since this device is a disconnect, controller & overload)Replaces All areas using Supplementary Protections

Motor Circuit

UL-508 M-CB

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UL 489 ApprovedMolded Case Circuit Breakers

UL 489 Mini-circuit breakersProducts evaluated according to the UL 489 Standard for Molded Case Circuit Breakers and are UL Listed for Branch Circuit Protection at 240 voltsThe CSA C22.2 No. 5.1 Standard is equivalent to the UL 489 Standard

SQD C60 UL-489

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UL 489 Mini-Circuit Breakers

Mini-Circuit Breakers approved as Molded Case Breakers under UL 489 may used as a as a B.C.P.D., branch-circuit short-circuit protection device.

Mini-Circuit Breakers approved as Molded Case Breakers under UL 489 may NOT be used as used as a Controller under 430-(81-91) nor can they be used as an overload relay under 430-32

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Applying A UL-489 Listed Branch Circuit Devices per UL-508A



240V or Less 3-Phase

BCPDCB or Fuse

Power Transformer Circuit

Motor

Power Transformer

UL-489 Permitted for Use as:Branch Circuit Protection DeviceMotor LoadsResistive Loads

Branch Circuit Protection Device

UL-489 MCB

UL-489 MCBOr MCB could be upstream from the Motor Starter

Motor Circuit

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Mini-Circuit Breakers approved as Molded Case Breakers under UL 489 are typically approved for 240 volts only.

240 volt approvals similar that applied to residential quick-lag molded cased breakers may not be applied as UL 489 circuit breakers at 480 volts

UL 489 Mini-Circuit Breakers

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Mini-Circuit Breakers are typically approved for 10KAICmaximum which is inadequate short-circuit fault protection for most multi-motor starter panels.

Mini-Circuit Breakers

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Fact: Customers are applying Mini-CBs incorrectly

Control panel builders and OEMs are responsible for compliance with NEC and UL and even having a UL508A approved Industrial Control Panel label does not release the responsibility IF the worst occurs and equipment incurs damage during a short-circuit or someone gets hurt.

How do I tell the customer hes doing it wrong?!?

The following is scripted presentation for learning more about Supplementary Protection and their applications. Because of so many different country and electrical codes this tends to be a very complex subject.So we have created this presentation to provide some basics before you discuss the new 1492-SP product with your customers.

If you are new to the world of Circuit Protection it is a must before you sell to your customers..

Cost Savings - Protecting loads is very important to both OEMs and End users. It has been made even more cost efficient with the new 1492-SP. The 1492-SP is significantly lower in price then the 1492-CB that we have discussed in the past. For example, the List Price for 1Pole, B Trip curve, 10 amp device is $50.00. The new 1492-SP 1Pole, B Trip curve, 10 amp device List Price is $28.00 Flexibility -Wide variety of protection from .5 amps to 40 amps (50 and 63 amps in IEC applications). International approvals for OEMs - UL, CSA, VDE (Verband Deutscher Electrotechniker - German Approval) , GL (Germanischer Lloyd), IEC, and CE.

SHOW SAMPLE OF PRODUCTSpace Savings - Reduced height product is only 3.125 (80mm) tall. Panel space can be saved with use of the 1/2 size (width) auxiliary and auxiliary signal contact accessories.Simplified Maintenance - The flag indicator indicates when the device has been tripped (red - on & green - off)Energy Limiting - The 1492-SP provides 10 to 20 times less let-through energy than conventional molded case breakers.

THIS SLIDE IS ONLY FOR APPLICATIONS WHERE THE PANEL / MACHINE WILL END UP IN U.S. & CANADA OR THERE IS A REQUIREMENT THAT COMPONENTS ARE RECOGNIZED AS MEETING UL OR CSA.The main application for the Supplementary Protectors is in Control Circuits. Both U.S. and Canadian National Electric Codes allow the use of supplementary protectors in Control Circuit Secondaries. Control Circuits are usually on the secondary of a Control Transformer. There are usually many loads on the Control Transformer Secondary like: PLC Outputs, Relay Coils, Solenoids, Power Supplies, Solid State Equipment and Test Equipment, I am sure you have many of these in your panels.

Also, they work on the Power Limited Circuits that reside on the secondary of a Control Transformer.







First lets look at a panel application and discuss different Circuit Types.A FEEDER Circuit is down stream from the incoming power of the Panel it is 3 Phases as some times may be part of a Disconnect. This is a Branch Circuit and requires UL 489 Molded Case Breaker or Branch UL rated Fuse (may be a UL Class J Fuse) and Fuse Holder.A POWER TRANSFORMER this circuit usually comes off the main FEEDER. This Circuit requires UL 489 Molded Case Breakers (MCCB) or Branch rated UL Fuses (may be a UL Class CC Fuse) and Fuse Holder.A MOTOR BRANCH CIRCUIT is the circuit coming off the main FEEDER and goes to Motors or Drives. These devices are UL508 Self Type E Manual Motor Controller, UL 508 Manual Motor Controllers or UL rated Fuse (may be a UL Class CC Fuse) and Fuse Holder. A CONTROL CIRCUIT PRIMARY wire may be protected by the main FEEDER Molded Case Breaker or UL Fuse. If so, the Transformer Primary can be protected by a UL 1077 Supplementary Protectors or UL rated Fuse (may be a Midget Fuse) and Fuse Holder.A CONTROL CIRCUIT SECONDARY & ITS LOADS can be protected by a UL 1077 Supplementary Protectors or UL rated Fuse (may be a Midget Fuse) and Fuse Holder.A POWER LIMTED CIRCUIT They are downstream from a CONTROL TRANSFORMER SECONDARY and can be protected by a UL 1077 Supplementary Protectors or UL rated Fuse (may be a Midget Fuse) and Fuse Holder.









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Single large motor grouped with small motorsSingle contactor controlling a group of motorsContinueSelect for Additional ReferenceNEC 430-87UL 508Group OLRs Location in Control CircuitGroup OLRGroup Rated OLRsAre Not BCPDsOLRs are not BCPD

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NEC 430-87 Number of Motors Served by Each Controller

Each motor shall be provided with an individual controller.

Exception:For motors rated 600 volts or less, a single controller rated at not less than the sum of the horsepower ratings of all the motors of the group shall be permitted to serve the group of motors under any one of the following conditions:

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Exception: a. Where a number of motors drive several parts of a single machine or piece of apparatus, such as metal and woodworking machines, cranes, hoists, and similar apparatus. b. Where a group of motors is under the protection of one overcurrent device as permitted in Section 430-53(a) c. Where a group of motors is located in a single room within sight from the controller location.

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M

M

M

M


Group Installation per 430-52 with (1) Main Contactor

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M

M

M

M


Group Installation per 430-53 a or b with (1) Main Contactor

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M

M

M

M


Group Installation per 430-53c with (1) Main Contactor

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A Unique Exception to NEC 430-52 & 53

SmallHP

LargeHP

Situation: One large motor and one small motor

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The preceding diagram depicts an example of a large HP starter with a small HP motor. This is typical of a small oilier pump for the much larger load.

Unique Exception allowed by UL508

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The preceding diagram depicts an example of a large HP starter with a small HP motor. This is typical of a small oilier pump for the much larger load.

According to 430-53C this arrangement would require a Group B.C.P.D. to protect both motor starters; except there is no Group Rated Overload available for 250 HP or similar large HPs.


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The unique exception which can be UL508 Labeled is:

If the additional starter(s) or other loads does not increase the short-circuit device beyond the maximum allowed by NEC 430-152 for the larger motor and the smaller loads are additionally protected by a B.C.P.D.s sized to the smaller loads; then a separate B.C.P.D. for the larger motor is not required.


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5 HP7.2 FLA

250 HP302 FLA


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Note:More than one small motor starter can be grouped according NEC 430-53C provided the small Group B.C.P.D. does not exceed the larger B.C.P.D. sized to protect the larger HP motor starter as well as the group.


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vs.

Overload Location in the Control Circuit

The Classic Locationon the Load - sideof the Contactor

Group Rated Overloadshould be Located on the Line - sideof the Contactor

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Overloads Up-steam of Contactors

NEC does not specify contactor & overload order of location in the circuit thus Group Rated Overloadsmay be located on the line side of the contactors.

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GROUP OLR = B.C.P.D.

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GROUP OLR = B.C.P.D.

Group Rated Overload Relays have Inverse-Time functions but are not Circuit Breakers per UL 489 thus not B.C.P.D.s

NEC 430-53C allows multiple motors to be protected by one B.C.P.D. if Group Rated Overload Relays are used and all other provisions are met.

This means that Group Rated Overload Relays do not replace individual Circuit Breakers (or Fuses) as B.C.P.D.s but rather individual B.C.P.D.s may be omitted and a single B.C.P.D. may be used to protect a Group Installation.

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The Motor Protection Consultants

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The Motor Protection Consultants

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Transcript of The Motor Protection Consultants