Electrical Fires

Question 1

Overheating of electrical equipment is

a) the most common cause of fires in buildings
b) usually the result of inadequate wiring
c) often due to over-sized fuses being installed
d) the result of blocked cooling fin passages
e) illegal in most provinces

Answer 1

a) the most common cause of fires in buildings

Question 2

Electrical circuit insulation

a) will never break down or deteriorate
b) requires replacement after 10 years
c) is not affected by temperature
d) will not burn
e) will deteriorate due to high temperatures

Answer 2

e) will deteriorate due to high temperatures

Question 3

Electrical connections

a) need only make contact, they need not be tight
b) will create large amounts of heat if not tight
c) can cause an arc if too tight
d) may operate on overload for specified durations
e) will not generate heat at any time

Answer 3

b) will create large amounts of heat if not tight

Question 4

Under the Canadian Electrical Code, if an area contains
hazardous concentrations of flammable gases or vapours under
normal conditions, electrical equipment must be designated
safe for use in an area classification of
a) Class 1, division 1
b) Class 1, division 2
c) Class 2, division 1
d) Class 2, division 2
e) Class 3, division 1

Answer 4

a) Class 1, division 1

Question 5

Under the Canadian Electrical Code, if an area contains dust
in the air, under normal operating conditions, in
concentrations high enough to produce explosive or ignitable
mixtures, the electrical equipment must be designed safe for
use in an area classification of
a) Class I, division I
b) Class I, division II
c) Class II, division I
d) Class II, division II
e) Class III, division I

Answer 5

c) Class II, division I

Question 6

According to the Canadian Electrical Code an area where
easily ignited material fibres capable of producing
combustible flyings are handled or manufactured would be
classified as a
a) Class 1, division 1
b) Class 1, division 2
c) Class 2, division 1
d) Class 2, division 2
e) Class 3, division 1

Answer 6

e) Class 3, division 1

Question 7

An example of a class “C” fire would be

a) a fire in an electrical panel
b) a fire in a trash bin
c) a fire in a fuel tank
d) a precious metals fire
e) a fire in a coal storage pile

Answer 7

a) a fire in an electrical panel

Question 8

When an electrical fire is discovered
a) the equipment may be left running if the fire is put out
with a C type fire extinguisher
b) the equipment should be de-energized as quickly as
possible
c) the equipment should be left running until a backup power
supply is available
d) the equipment may be immediately restarted once the fire
is extinguished
e) fresh air should be provided to the room as quickly as
possible to get rid of toxic fumes

Answer 8

b) the equipment should be de-energized as quickly as

possible

Question 9

The best type of fire extinguisher to use on a live
electrical fire is a
a) pressurized water extinguisher
b) dry chemical extinguisher
c) purple K extinguisher
d) AFFF extinguisher
e) carbon dioxide extinguisher

Answer 9

e) carbon dioxide extinguisher

Question 10

The temperature of the carbon dioxide leaving the
extinguisher horn can be as low as
a) 0 degrees C
b) -5 degrees C
c) -30 degrees C
d) -60 degrees C
e) -80 degrees C

Answer 10

e) -80 degrees C

Question 11

Halon from halon fire extinguishers
a) produces a distinct odour which warns of the presence of
halon
b) is abrasive to electrical equipment
c) will act as a conductor if moisture is present
d) is derived from bromine, fluorine, or chlorine
e) is corrosive

Answer 11

a) produces a distinct odour which warns of the presence of

halon

Question 12

You discover that a small fire has been started in a high
tension switch box. In your immediate area there are four
different types of fire extinguishers. The one you put the
fire out with should be the
a) soda - acid extinguisher
b) dry chemical extinguisher
c) chemical foam extinguisher
d) cold water extinguisher
e) one closest to you

Answer 12

b) dry chemical extinguisher

Question 13

During annual turnaround of a facility it is highly
recommended that
a) all fuses in the electrical system be replaced
b) aluminum wiring be replaced
c) all electrical connections be checked for tightness and
corrosion
d) all circuit breakers be disassembled and cleaned
e) a megger be used on all electric motor windings

Answer 13

c) all electrical connections be checked for tightness and

corrosion

Question 14

Temporary electrical hook-ups should

a) be in place for a maximum duration of 72 hours only
b) be made with BX electrical cable
c) be designed to the original specifications
d) comply with the ASME codes
e) have CSA pre-approval

Answer 14

c) be designed to the original specifications

Question 15

A common cause of an electrical fire is
a) allowing motors or conductors to get wet if not designed
for that purpose
b) prematurely replacing deteriorated wiring
c) following too closely to the Electrical Code when
installing electrical equipment
d) replacing burned fuses with ones of the same rating
e) waiting a specified amount of time between attempts to
start large motors

Answer 15

d) replacing burned fuses with ones of the same rating