103H Arc Flash & Electrical Safety

Question 1

The probability of arch flash

Answer 1

1. Condensation
2. Material failure
3. Corrosion
4. Dust on exposed energized conductors or circuit parts

Question 2

Potential effects of exposure resulting from an arc flash

Answer 2

1. Temperature as high as 20000C(36000F) resulting in server burns/fire
2. Shrapnel
3. Arc blast pressure
4. Noise up to 165dB
5. Infrared(IR) & ultraviolet(UV) radiation
6. Toxic vapours
7. Copper expands by 67000 times

Question 3

3 factors that determine the severity of an injury due to an arch flash are:

Answer 3

1. The proximity (가까움)
2. The amount of heat
3. The time

Question 4

The distance from an arcing fault at which a person may be exposed to an incident energy of 1.2 calories/cm² with bare skin during an arc flash is

Answer 4

Arc flash boundary

Question 5

Class of Equipment

High-voltage switchgear
Low-voltage switchgear
Low-voltage motor control centre (MCC) & panelboards

Answer 5

Typical Working Distance

910 mm (36”)
610 mm (24”)
455 mm (18”)

Question 6

PPE is your

Answer 6

Last line of defense

Question 7

What Class are goggles classified as by the CSA Standards?

Answer 7

2

Question 8

What is the CSA Standard that all safety glasses must meet?

Answer 8

CSA Z94

Question 9

3 characteristics of clothing that the CSA Z462 Workplace Electrical Safety Standard considers when selecting them for PPE?

Answer 9

1. Resists catching on fire
2. Self-extinguishing
3. Provides thermal insulation from heat radiation

Question 10

What does the acronym ATPV stand for?

Answer 10

Arc Thermal Performance Value

Question 11

What are lockout procedures?

Answer 11

A series of steps to follow to prevent equipment from being energized while someone is working on the equipment

Question 12

6 steps to follow when locking out and then re-energizing a piece of equipment?

Answer 12

1. Warn personnel
2. Use proper shutdown procedure
3. Disconnect equipment from the supply
4. Padlock & tag equipment
5. Confirm
6. Re-energize

Question 13

What is the maximum allowed number of keys that may open a padlock used for lockout purposes?

Answer 13

1