Module 2 Test Questions Electrical Study Deck Flashcards
Service entrance conductors run from the service drop to the service box or service panel. T/F
True
The service size is determined by the amperage and voltage ratings of the service. T/F
True
Is the service drop overhead or underground?
overhead
Are service laterals overhead or underground?
underground
The drip loop is typically part of the service drop. T/F
False
The wire size for the service drop must be the same as the wire size for the service entrance conductors. T/F
False
How many wires would you typically find in a 240-volt service drop?
3
What would 4 wires mean?
Three phase electricity
What would 2 wires usually mean?
120 volts service
List 7 common problems with service drops.
overhead wires too low, damaged or frayed wires, trees or vines interfering with wires, wires too close to doors or windows, wires not well secured to the house, poor connection between service drop & service entrance, inadequate clearance from roofs
List clearances above ground, swimming pools, and roofs.
above roadway-18 ft
above driveway-12 ft
above flat roof-8-10 ft
above sloped roof-18 inches
away from water in pool-22 1/2 ft in any direction
3 feet above sloped roof w/pitch greater than 4 in 12
above walkway-10 ft
The service entrance conductors run from the __ to the __.
from service drop to the service box
All service entrance conductors must be in conduit. T/F
False
All service entrance conductors must be attached above roof level. T/F
False
The drip loop should be as close to the roof surface as possible. T/F
False
List 10 common problems with service entrance conductors.
No drip loop
No mast head
Mast head not weather-tight
Mast or conduit bent
Mast or conduit rusted
Mast rotted
List 4 common areas of water penetration into service entrances.
Conduit joints, mast head, roof flashing, meter base
List 2 functions of the drip loop.
prevents water entry into the conduit or service entrance, shows that the service drop wires are not straining the splice (???)
Roughly 999 out of 1,000 houses have __ volts available
240
Roughly 999 out of 1,000 houses have __ service entrance wires
Three
Load calculations are part of a home inspection. T/F
False
Implications of an undersized service include:
a. shock hazard
b. fire hazard
c. shock & fire hazard
d. melting insulation
e. nuisance tripping of the main fuses or breakers
nuisance tripping of the main fuses or breakers
What is the largest single-phase service that you are likely to find in a home?
400 amps
What size copper wire would you expect to find on the service entrance for:
a. A 60-amp service
b. A 100-amp service
c. A 200-amp service
a. 6 gauge
b. 4 gauge
c. 2-0 gauge
Which of the following is a reliable way to identify the service size? (Need answer choices)
Aluminum is an acceptable service entrance conductor material. T/F
True
A fused 200-amp service has two 100-amp fuses in the service box. T/F
False
If you can’t read the size of the fuses in the service box, you should remove them to try to get a better look. T/F
False
Which of the following is a safety issue?
a. main fuses have lower rating than service entrance wire
b. main fuses have higher rating than service entrance wires
c. service box has higher rating than service entrance wires
d. service box has same rating as service entrance wires
e. distribution panel has larger rating than service entrance wires
main fuses have higher rating than service entrance wires
Service box can be inside, outside or in a garage. T/F
True
There can be up to 10 throws to disconnect all of the electricity in….. T/F
False
The service box may stand alone or may be combined with the…panel T/F
True
List 16 common conditions you might find in a service box
poor access/location, loose, rust or water in box, unprotected opening, damaged parts, overheating, poor connections, illegal taps, neutral wire by -passes service box, fused neutral wire, obsolete box, box not rated for aluminum
The functions of earth grounding systems include:
grounding systems can help dissipate electricity from lightning, grounding systems can help avoid the build up of static electricity
The grounding electrode conductor may be called:
grounding electrode conductor is the ground wire
You are allowed to ground to the gas piping. T/F
False
The grounding systems are connected to the house neutral at the __.
service box
From the point where the ground and the neutral wires connect, there are two paths to ground. What are they?
through the neutral service wire or through the grounding electrode conductor to water pipes or ground rods
List 5 destinations where ground wires can terminate.
metal water supply pipes
metal rods driven into the ground
wires buried in the footings of buildings
buried grounding plates
frames of metal buildings
metal well casings
List 12 common problems found with grounding systems.
no grounding
ground wire attached to plastic pipes
ground wire after meters & valves with no jumper
spliced ground wire
poor connection
ground connections not accessible
ground rod cut off
corroded ground rod
undersized ground wire
neutral bonded to ground wire after service box
service box not bonded to ground wire
no ground in sub panel feeder wires
Distribution panels are also called (6 if you can):
service panels, panelboards, auxiliary panels, sub panels, fuse boxes, fuse panels, breaker panels
Wires run directly from the service box to the branch circuits. T/F
False
What is the advantage of a 240-volt circuit?
more electricity can flow at lower amperage ratings
What size copper wires are adequately protected by:
a. 15-amp breaker
b. 20-amp breaker
c. 30-amp breaker
d. 40-amp breaker
a. 15-amp breaker-14 gauge
b. 20-amp breaker-12 gauge
c. 30-amp breaker-10 gauge
d. 40-amp breaker-8 gauge
What size wire is found on most general purpose outlets for lights and receptacles?
14 gauge
Which of the following is a safety concern?
a. fuse too small
b. fuse too big
fuse too big
Subpanels must be immediately adjacent to the main panel. T/F
False
Typical distribution panels have 60 circuits T/F
False
Do we normally shut off power when looking at an electrical system in a house? Why or why not?
We do not shut off power. This would be a significant inconvenience to the occupant.
List 14 conditions that may be found in all panels
obsolete and/or fused neutrals
damaged panel
loose or missing door
openings in panel
panel too small
overheating
rust or water in panel
circuits not labeled
panel crowding
poor access
upside down
Explain why fused neutrals are a bad idea.
dangerous because the fuse on the neutral side only blows. The circuit may not work, but there may be voltage throughout the entire circuit
What is the implication of a panel that is too small for the service?
panel may overheat
Should the neutral & the ground wires be bonded together at the subpanel?
No. Electricity may flow through the ground wire under normal circumstances. The ground wire should be reserved for emergency situations.
How should the feeder wires to a subpanel from the main panel ideally be protected?
a. no fusing necessary
b. main house fuses or breakers will protect wire
c. fuses should be provided at subpanel
d. fuses should be provided at main panel
e. none of the above
fuses should be provided at main panel
What are implications of oversized breakers?
oversized breakers will allow wires to overheat w/out tripping
What does the term “double tap” mean?
2 wires connected to single terminal
The red and black wires of multi-wire circuits should be on separate bus bars. T/F
True
List 4 common problems found only with breakers
- multi-wire circuits not linked
- too many breakers
- wrong breaker in panel
- loose breakers
List 6 problems found with wires in panels
- sheathing not removed
- overheating
- loose connections
- damaged
- not well secured
- wires crossing bus bars
- abandoned wires in panel
What is a split receptacle?
split receptacle has the top part of the outlet on one circuit and the bottom part on a different circuit
What is meant by linking in multi-wire branch circuits?
linking means that the fuses or breakers for multi-wire branch circuits have to be shut off in pairs
List 2 different branch wire materials you might see
copper, aluminum
Describe 3 different cable types you might see
- NM, Romex, Loomex
- UF
- BX, armored cable
- Knob-and-Tube
What is the difference between insulation and sheathing?
Insulation is around the individual wires, and sheathing forms the cables by wrapping around the insulated wires
The most common wire size for branch household circuits is __ gauge
14
What are the issues on running wire through steel studs?
Wire may be damaged by sharp edges of steel studs. Wires passing through holes should be protected with grommets, for example, wires running parallel to studs should stand off the studs
List 5 common branch circuit wire problems
damaged, not well secured, loose connections, open splices, wires too close to ducts, pipes, vents, wires run through steel studs w/out protection, abandoned wire, cable used outdoors, exposed wire in attic, undersized wire
Give 4 examples of damaged wire.
cut or pinched, chewed on by animal, burned wire, brittle or cracked insulation
List 3 methods for securing wire ends.
- terminal screws
- push-in connectors
- solderless connector
What is meant by open splice?
open splice is a connector that is not made ….?????
Wire should be _ inches away from edge of studs
1 1/4”
A grommet is:
fitting that protects cable from………studs…..?
Wires should not be run on wall surfaces without___.
mechanical protection
What is the problem with running wires across the top of the attic ceiling joists?
not visible and may be stepped on
Abandoned wire should be__
removed
Describe how knob-and-tube wiring is visibly different from modern cable?
Need complete answer
Does knob-and-tube wiring have a ground wire associated with it?
No
List 4 common problems with knob-and-tube wiring
connectors not in boxes, brittle, buried in insulation, fused neutrals
List 3 common problems found with aluminum wiring
connectors not compatible with aluminum, no anti-oxidant grease on stranded wire, overheating
How would you identify aluminum wiring?
the conductor itself is silver colored. The sheathing usually has the word aluminum, alum or Al
When was aluminum wiring used?
aluminum wiring was used from the mid 1960s to the late 80s
What caused problems with aluminum wiring?
- tends to creep out from under terminal screws
- forms corrosion that is an electrical insulator
- is softer than copper & easier to damage when working with the wire
- was, in some of early material, low quality wire prone to weakness & breaking
Where is the anti-oxidant grease typically used?
anti-oxidant grease is typically used on stranded aluminum wires
List 12 common lighting problems fond in houses?
damaged, loose, overheating, inoperative, obsolete, not grounded, missing, poor stairway lighting, heat lamps over doors, isolating links needed on pull chains, improper closet lighting
How are lights tested?
by turning them on and off by their switches
Why should heat lamps not be located over doors?
A towel thrown over the door may be ignited by a heat lamp
List 14 common receptacle problems
damaged, loose, overheating, ungrounded outlets, open neutral or open hot connections, reversed polarity outlets, inoperative, wrong type receptacle, no GFIs, overheated neutral on split receptacles, worn receptacles, broken pin or blade in slots, too far from basins
Describe how you would test a GFI receptacle during an inspection
use a conventional circuit tester and operate the test button on the receptacle
Explain the problem with reversed polarity
the collar of a light fixture may be energized, increasing the risk of electrical shock when changing a light bulb
Can an outlet be protected by a ground fault interrupter without it being apparent?
yes, all outlets downstream of a GFI outlet will be protected
Outlets should be close to basins. T/F
True
List 4 common problems found with switches
damaged, loose, overheating, inoperative
All junction boxes should be concealed. T/F
False
List 7 common junction box problems.
damaged, missing, loose, not grounded, cover loose or missing, crowded, concealed boxes
Knob-and-tube wiring was commonly installed without junction boxes. T/F
True
One smoke detector is needed in each home, near the kitchen because that’s where most house fires start. T/F
False
