Ch. 5
What switch type and rating is required to control five 300-watt tungsten filament lamps on a 120-volt circuit? Show Calculations.
15 amp t-rated AC 1500 volt amps/120= 12.5 Fthe instamps
What type of switch is installed to control a luminaire from two different control points? How many switches are needed and what type are they?
3 way switches 2 of them are used
If you had to install an underground 3-wire feeder to a remote building using three individual conductors, which of the following installations "Meets Code"? Circle the correct installation on question 18 in the book.
B
What section of the Code emphasizes the fact that all circuiting must be done so as to avoid the damaging effects of induction heating ?
NEC 300.20(A)
Is it always necessary to attach the bare equipment grounding conductor of a nonmetallic-sheathed cable to the green hexagon-shaped grounding screw on a receptacle? Explain.
No it is the most secure grounding method but on metallic boxes grounding can be attached to the box itself as long as there is a metal to metal connection between the yokes and the metallic boxes
Define an equipment grounding conductor.
The conductive path(s) that part of an effective ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both.
Match the following switch types with the correct number of terminals for each. Three-way switch, single-pole switch, four-way switch
Three-way switch: 3 terminals , single-pole switch: 2 terminals, four-way switch: 4 terminals
When metal toggle switchplates are used with nonmetallic boxes, the faceplate must be grounded according to NEC 404.9(B). How is this accomplished?
by bringing a bare copper grounding wire directly to a grounding terminal on the metal switch plate.
When connecting 4-way switches, care must be taken to connect the travelers to the ________ terminals.
correct
List the methods by which an equipment grounding conductor is connected to a device box.
grounding screw and grounding clip
Single-pole switches are always connected to the _______ wire.
hot
Explain how lighting switches are rated.
it depends if it is an inductive load (such as in motors where the voltage wave is ahead of the current wave) or a resistive load (where the two waves are together aka in phase
Does the Code permit connecting receptacles to a 20 ampere branch circuit using short lengths of 14 AWG conductors as the pigtail between the receptacle terminals and the 12 AWG branch-circuit conductors?
no it does not
Does the Code permit the ampacity of switch legs to be less than the ampere rating of the branch circuit?
no it must be the same
Do the receptacles that have back-wired push-in terminals accept 12 AWG conductors? Give a brief explanation of your answer.
no only 14 AWG fits in the push terminals
When two nonmetallic-sheathed cables (Type NM-B) enter a box, is it permitted to bring both of the bare equipment grounding conductors directly to the grounding terminal of a receptacle, using the terminal as a splice point?
no you cannot do loop wiring with 2 wires under a single terminal NEC 250.148
The installation in the accompanying drawing is wired with EMT. Receptacle outlet B is only a few feet from switch C. Receptacle outlet A is only a few feet from switch D. The electrician saved a considerable amount of wire by picking up the supply (feed) for switch C from receptacle B, and the switch leg (return) from switch D. What is wrong with this installation? (See question 22 in the book)
nothing is cancelling out induction heating can occur 300.20(A)
A T-rated switch may be used to its ________ current capacity when controlling an incandescent lighting load.
rated
List four types of lighting switches.
single pole, 3-way, 4-way, double-pole, switches with pilot light
A three way switch may be compared to a _______ switch.
single pull double throw
To control a lighting load from one point, what type of switch would be used?
single pull switch
When connecting single-pole, 3-way, and 4-way switches, they must be wired so that all switching is done in the _______ circuit conductor.
ungrounded (hot)
The identified ground circuit conductor must be _________ or _________ in color.
white grey
