SS & IEC Requirements for MCB & RCCB - ABB Ltd · SS & IEC Requirements for MCB & RCCB By NS Koh...
Transcript of SS & IEC Requirements for MCB & RCCB - ABB Ltd · SS & IEC Requirements for MCB & RCCB By NS Koh...
© ABB Group July 6, 2011 | Slide 1
by NS Koh
ABB Pte. Ltd.
SS & IEC Requirements for MCB & RCCB
By NS Koh
Since the withdrawal of SS 359 on 30th Jan 2004, International Standard IEC 60898 was adopted for MCB.
IEC 60898 : Circuit-breaker for overcurrent protection for household and similar installation
Scope : AC air-break circuit-breakers 50Hz or 60HzUn < 440VIn < 125AIcn < 25kA
Designed for use by uninstructed people and for not being maintained
SS & IEC Requirement for MCB & RCCBMCB
Overcurrent protection
Overload protectionProtection of cables and wires aswell as system parts againstexcessive heating up duringoperating overload in a fault-freecircuit by delayed switch-off
Short-circuit protectionProtection of cables and wires aswell as system parts against theeffects of a dead short-circuitbetween conductors with adifferent potential by current-limiting switch-off
Protection of cables and wires in case of overcurrent
Thermal Tripping Magnetic Tripping
SS & IEC Requirement for MCB & RCCBMCB
SS & IEC Requirement for MCB & RCCBMCB Tripping Characteristics
IEC 60898 Termal Release Trip time Electromagnetic Release Trip time
Type Non-trip Trip Hour Hold Trip sec
B 1.13 In > 1 3 In > 0.1
1.45 In < 1 5 In < 0.1
C 1.13 In > 1 5 In > 0.1
1.45 In < 1 10 In < 0.1
D 1.13 In > 1 10 In > 0.1
1.45 In < 1 20 In < 0.1
SS & IEC Requirement for MCB & RCCBMCB Tripping Characteristics
0.5 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
0.5 ms
1 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
1 ms
1.5 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
1.5 ms
2 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
2 ms
2.5 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
2.5 ms
3 ms after short-circuit current is released
Miniature Circuit BreakersTripping of an MCB
3 ms
SS & IEC Requirement for MCB & RCCBMaximum disconnection times: TN-S System
3ms
SS & IEC Requirement for MCB & RCCBRCCB
SS97 is a modified adoption of International Standard IEC 61008-1
SS97 & IEC 61008-1: Residual current operated circuit-breakers without integral overcurrent protection for household and similar uses (RCCBs)
Scope : Functionally Dependent of or Independent on line voltage Un < 440VIn < 125A
Protect person against indirect contact and fire hazards due to earth persistent fault
SS & IEC Requirement for MCB & RCCBRCCB
Major difference between SS97 and IEC 61008-1 is the tripping time:
General Type Max Break Times (s)
Standard Category 1 x I n 2 x I n 5 x I n 10 x I n, to 500A
IEC 61008 n < 30mA 0.3 0.15 0.04 0.04
SS 97 n< 30mA 0.1 0.1 0.04 0.04