Electrical Flashcards
Which of the following installations is UNSAFE?
a) NM wire in a detached garage
b) 8 gauge wire on a 30 amp circuit
c) 12 gauge/2 conductor wire servicing a baseboard heater
d) NM wire under a sandbox
e) knob-and-tube wire joined to new wiring in a junction box
D@
All of the breakers in a service panel are white, except one, which is black. You should be checking
a. that the black breaker is correctly sized for the wire.
b. that the black breaker is suitable for use in the panel, if this is determinable.
c. that the black breaker isn’t loose.
d. All of the above
D
you should check that the breaker is properly sized and is compatible with this panel. you should make sure that it was a professionally installed (and not forced into place) and that the breaker isn’t loose.
Problems with aluminum wiring include all of the following EXCEPT that
a. it tends to creep.
b. it lacked a ground wire.
c. the aluminum oxide is not a good conductor of electricity.
d. aluminum is softer than copper and easier to damage.
B@
Lacking a ground wire is not a common problem with aluminum wire.
Which type of wire is rated for underground use?
a) UF or NMWU
b) NMW
c) NMDU
d) BXU
e) UUDW
A@
Electrical ground wires may attach to all of these, EXCEPT:
a. Ground rods
b. Water supply pipe
c. Buried footing
d. Floor joist
D
Extension cords are typically
a. stranded wire.
b. solid wire.
c. designed to be held in place with staples.
d. best protected if run under carpets.
A@
Extension cords are typically stranded wire. This is so they will be more flexible than solid wire.
The end of the neutral wire from a 3-conductor cable is overheating. The reason for this could be any of these except
a) the wire is loose
b) the circuit breakers are undersized
c) both sides of the multi-wire circuit are drawing from the same bus
d) the wire is nicked
e) the wire is aluminum
B!
Water stains on the soffit around the hole where service mast passes through is most likely the result of
a. improper flashing where the mast penetrates the roof.
b. a lack of a drip loop.
c. a lack of caulking between the soffit and the mast.
d. a cracked masthead.
A!
Water stains on the soffit, where the mast goes through the roof, usually indicate a flashing problem.
Which of the following would least likely to be found on a dedicated circuit?
a) baseboard heater.
b) furnace
c) ceiling fan
d) dishwasher.
e) food waste disposal (disposer)
C@
Is it permissible to use an aluminum grounding wire?
A) Only if it is at least #3 AWG.
B) Yes.
C) Only in some provinces and states.
D) Only in dry environments in the United States.
D!
During an inspection you find 20 blown 15-amp fuses beside the panel. You might tell your client
A) it’s likely that there is at least one overloaded circuit in the panel.
B) the 15 amp fuses should be replaced with a larger fuse size that will not blow.
C) there must have been several defective fuses purchased, perhaps from one bad lot.
D) it’s likely that there is a defect in the panel.
A@
Which is the least common type of connection for branch circuit wiring seen in a new house?
a) bayonet
b) Marr®
c) screw
d) soldered
e) twist-on
D@
Overloading the neutral wire on a multi-wire branch circuit
A) means that the neutral wire was undersized.
B) indicates a short in the circuit.
C) is the result of failing to fuse the neutral.
D) is likely if the black and red wires are powered from the same bus.
D@
What factor determines the electrical service size to a house?
a. The size of the drip loop
b. The size of the meter
c. How close the house is to the transformer
d. The size of the service entrance wires
D
Ohm’s Law, the relationship between voltage, current, and resistance in a simple circuit, states that
a. V=lR.
b. l=VR.
c. R = IlV.
d. V=UR.
A!
V=IR.
All of the following are panel wire problems EXCEPT
a. overheating.
b. wires crossing bus bars.
c. sheathing removed.
d. abandoned wires.
C
Sheathing that has been removed on the panel wires is not a problem.
Attic wires should not ordinarily be run on top of ceiling joists unless
a) the headroom is less than 40 inches
b) plywood covers them
c) insulation covers them
d) they are visible
e) it is certain that animals won’t gain access
A@
Special grease on aluminum wires is
a. found on number 12-gauge and 10-gauge wires.
b. found on stranded wires.
c. found on service entrance wires only.
d. used to control creep.
B@
The special grease on aluminum wires is typically used on stranded wires.
These are all possible causes for an inoperative light, EXCEPT:
a. Bulb burned out
b. Faulty light fixture
c. Poor connection in box
d. Missing grounding wire
D
A special grease is applied to larger gauge aluminum wires to
a) reduce slippage
b) improve conveyance
c) help identify the wire as aluminum
d) inhibit corrosion
e) dissipate heat.
D@
If two 60-W light bulb branch circuits are wired in parallel, and another parallel 60-W light bulb branch circuit is added
a. the bulb closest to the voltage source will be brightest.
b. each bulb will have the same brightness.
c. the total current in the circuit stays the same.
d. the current in each branch will decrease.
B!
In a parallel circuit, any bulbs that you add will have the same brightness, so long as the circuit is not overloaded.
What is the correct fuse or breaker size for 8 gauge AWG copper wire?
a. 15 amps
b. 20 amps
c. 30 amps
d. 40 amps
D
Overheated wires may have resulted from all of the following EXCEPT
a) underfusing
b) a loose connection
c) a nicked wire
d) an undersized wire
e) proximity to a water heater vent
E@
Knob-and-tube wiring issues include all of the following EXCEPT
a. connections to modern wire not in boxes.
b. wires buried in insulation.
c. brittle wire, insulation, or sheathing.
d. overheated neutrals on multiwire branch circuits.
D@
Overheated neutrals on multiwire branch circuits are not specific to knob and tube wiring. Multiwire branch circuits are, in fact, very rare on knob and tube wiring.