Safety

Safety Overview

Objectives:

• State basic safety rules.

• Describe the effects of electric current on the human body.

• Discuss the responsibilities of OSHA.

• Discuss lockout and tagout procedures.

Safety Overview

Objectives:• Explain proper placement of a straight

ladder.• Discuss the use of scaffolds.• Discuss classes of fires.• Discuss ground-fault circuit interrupters.• Discuss the importance of grounding.

Safety OverviewGeneral Safety Rules

• THINK FIRST! This is the most important safety rule!

• Never work on an energized circuit if it is possible to disconnect the power.

• Avoid horseplay.• Do not work alone.• Work with one hand when possible.• Learn first aid and CPR.

Safety OverviewGeneral Safety Rules

• The OSHA mission is to ensure safe and healthy workplaces.

• Avoid using alcohol and drugs in the workplace.

• Avoid walking close to trenches.• Don’t jump over trenches, walk around

them.• Place barricades around trenches.

Safety OverviewGeneral Safety Rules

• Use ladders to enter and exit trenches.• Always maintain an outside person to

monitor people working in confined spaces.• Lockout and tagout procedures prevent

accidental energizing of circuits.• Scaffolds provide the safest elevated

working platform.

Safety Overview

A safety tag used to tagout equipment.

Safety Overview

The OSHA lockout and tagout procedures prevent electrical accidents!

Safety OverviewGeneral Safety Rules

• A straight ladder should be positioned so that its bottom is placed away from the wall a distance of ¼ the vertical height of the ladder where it touches the wall.

• Ground-fault circuit interrupters (GFCI) are used to protect people from electrical shock.

• NEC 250 refers to grounding requirements.

Safety Overview0.100-0.200AMPERES

0.060-0.100AMPERES

0.040-0.060AMPERES

0.030-0.040AMPERES

0.020-0.030AMPERES

0.010-0.020AMPERES

0.009-0.010 (MODERATE SENSATION)

0.002-0.003AMPERES

(SLIGHT TINGLING SENSATION)

(BREATHING DIFFICULTY)

(MUSCULAR PARALYSIS)

(UNABLE TO LET GO OF THE CIRCUIT)

(VERY PAINFUL)

(DEATH) THIS RANGE GENERALLY CAUSES FIBRILLATION OF THE HEART. WHEN THE HEART IS IN THIS CONDITION, IT VIBRATES AT A FAST RATE LIKE A "QUIVER" AND CEASES TO PUMP BLOOD TO THE REST OF THE BODY.

(EXTREME DIFFICULTY IN BREATHING)

Effects of electric current on the human body.

Safety Overview

A GFCI device monitors both the hot and neutral currents. These currents should be equal!

Safety Overview

Unequal currents may mean an unwanted pathway through a person! This is a ground fault.

Safety Overview

One type of GFCI device is a special circuit breaker.

Safety Overview

Another type of GFCI device is a special receptacle.

Safety Overview

• Fires can be divided into four classes:– Class A: wood and paper– Class B: grease, liquids, and gases– Class C: energized electric equipment– Class D: metals

Safety Overview

Review:

1. Never work on an energized circuit if it is possible to disconnect the power.

2. Avoid horseplay.3. The most important rule of safety is to

think first.4. Do not work alone.5. Work with one hand when possible.

Safety Overview

Review:

6. A current of 100 to 200 milliamperes passing through the heart generally causes death.

7. The mission of OSHA is to ensure safe and healthy workplaces.

8. Learn first aid and CPR.9. Avoid using alcohol and drugs in the

workplace.

Safety OverviewReview:

10.Don’t walk close to trenches unless it is necessary.

11.Don’t jump over trenches; walk around them.

12.Place barricades around trenches.

13.Use ladders to enter and exit trenches.

Safety Overview

Review:

14.When working in confined spaces, an outside person should keep in constant contact with the people inside the space.

15.Lockout and tagout procedures are used to prevent someone from energizing a circuit by mistake.

Safety Overview

Review:

16.The bottom of a straight ladder should be placed a distance from the wall equal to one fourth the height where the top of the ladder makes contact with the wall.

17.Scaffolds generally provide the safest elevated working platform.

Safety Overview

Review:

18.Fires can be divided into four classes: Class A is common items such as wood or paper; Class B is grease, liquids, and gases; Class C is energized electric equipment; and Class D is metals.

19.Ground-fault circuit interrupters are used to protect people from electric shock.

Safety OverviewReview:

20.GFCI protectors open the circuit when approximately five milliamperes of ground-fault current are sensed.

21.NEC® 250 lists the requirements for grounding electrical systems.