IEC 213

A very long branch circuit has been installed underground in Schedule 40 PVC. The circuit extends from a 120/208-volt, 3-phase, 4-wire panelboard to the load. The branch circuit conductors are connected to a 20-A circuit breaker in the panel. Due to voltage drop considerations, 1 AWG circuit conductors have been installed. The smallest EGC that can be installed in the PVC is ___ AWG or kcmil.

1

Where installed in a 3-pole, 600-volt fused safety switch, the minimum number of fuses required to protect a 120-volt, 1-ph, 2-wire branch circuit is ___.

1

Where a cable or raceway-type wiring method is installed through bored holes in joists, rafters, or wood members, holes shall be bored so that the edge of the hole is not less than ___ from the nearest edge of the wood member.

1 1/4 inch

The secondary of a 300 KVA, 480 - 240-volt Δ-Δ transformer is delivering 100 amps to 3Ø loads. Based on this load, the smallest permitted primary and secondary conductors are installed. Refer to Scenario 223.51. The maximum rating of the primary OCPD is ___ A.

100

Where the service-entrance phase conductors are larger than 1100 kcmil copper or 1750 kcmil aluminum, the main bonding jumper shall have an area that is not less than ___% of the area of the largest phase conductor.

12 1/2

If the allowable current rating of a busway is 1400 amps, what is the maximum allowable rating of the overcurrent protection device that may be used to protect the busway?

1200 amps

What is the maximum voltage between circuit conductors when using plug fuses?

125

A size ___ AWG equipment grounding conductor is contained in a nonmetallic-sheathed cable marked as 14 AWG.

14

When the corrected ampacity of a 10 AWG copper conductor is 12.86 amps, the maximum size circuit breaker permitted to protect the conductors is ___.

15

Underground service conductors that are not encased in concrete and that are buried ___ or more below grade shall have their location identified by a warning ribbon that is placed at least 12 inches above the underground installation.

18 inches

A ground ring must be at least ___ feet long.

20

One conduit is run from Panel LA to a pull box as shown in Figure 205.13. The 250-amp breaker has 250 kcmil circuit conductors connected to it, and 500 kcmil circuit conductors are connected to the 400-amp breaker. Only one grounding conductor is required in this conduit for all contained circuits. The smallest EGC permitted to be installed in the conduit between the panel and the pull box is ___ AWG. The upper breaker feeds Load 1 and has a rating of 250 A. The lower breaker is rated at 400 A and feeds Load 2.

3

According to 240.4(D)(7), the largest circuit breaker that can be used to protect a circuit that uses 10 AWG conductors has a rating of ___ A.

30

___ AWG is the smallest size copper wire permitted to be used as a GEC to building steel from 200 A main breaker Panel LC. As shown above in Figure 205.8, the panel is fed from a transformer with one set of 3/0 AWG wire.

4

If connected to a metal water piping system, the grounding electrode conductor shall be connected at some point within the first ___ of where it enters the building.

5 ft (1.52 m)

A dwelling service entrance is rated at 150 amperes and the service-entrance conductors are size 2/0 AWG aluminum with 75°C insulation and terminations. The minimum size copper grounding electrode conductor permitted to the metal underground water pipe is ___ AWG.

6

Lengths of flexible metal conduit longer than ___ feet are not acceptable as an equipment grounding conductor. In such cases a separate bonding jumper is required to be run outside of the flexible conduit to maintain the continuity of the grounding path.

6

Select the size of the aluminum equipment grounding conductor required for a circuit protected by a 70-ampere fuse.

6 AWG

When eight (8) current-carrying conductors are in one conduit, the ampacity of each conductor is adjusted to ___ percent.

70

A conductor has a computed ampacity of 75 amps. What is the maximum standard ampere rating of the overcurrent protection device the NEC® permits to protect this circuit? This is not a motor circuit or part of a multioutlet branch circuit supplying receptacles.

80 amperes

Circuit breakers shall be marked with a voltage rating not less than the nominal system voltage that is indicative of their capability to interrupt fault currents ___. I. between phases II. from phase to ground III. between the neutral and ground

I & II only

Section 240.21(C)(6) in the NEC® is the "25 foot rule." This section requires that the secondary conductors be 25 feet or shorter in length and ___. I. have an ampacity that is ≥ [(Pri OCPD ÷ 3) × (Epri line ÷ Esec line)] II. have an ampacity that is ≥ the rating of the circuit breaker or fuses at the end III. be installed in a raceway or otherwise protected from physical damage

I, II, & III

Systems are grounded to provide a path for ___. I. fault current II. lightning III. short-circuit currenT

II only

Handles or levers of circuit breakers, and similar parts which may move suddenly in such a way that persons in the vicinity are likely to be injured by being struck by them, shall be ___. I. concealed II. isolated III. guarded

II or III only

Refer to Figure 205.2. Point ___ is the grounding electrode conductor.

V

If a fuse label is not marked with a fuse interrupting rating, the fuse size has ___.

an interrupting rating of 10,000 amps

A 240-volt load, such as a window unit air conditioner, would require breaker ___ to be installed in the panelboard.

b

The conductor shown above at Point III in Figure 205.1 connects the ___ to the grounded conductors. I. metal panel enclosure II. equipment grounding conductors

both I & II

The grounding electrode conductor shall be ___.

copper, aluminum, or copper-clad aluminum

A 120-volt cord-and-plug connected appliance is permitted to have a two-wire cord ("hot" & neutral) and attachment plug instead of a three-wire cord ("hot," neutral & ground) when the appliance is ___.

double insulated

The scope of Article 250 covers all of the following topics, except for ___.

grounding requirements for surge protection

Unless specifically listed for them, a surge-protected device is not permitted on a(n) ___ system.

impedance-grounded

Not more than one conductor shall be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is ___.

listed for multiple conductors

You are to run a circuit underground in PVC conduit from a service panelboard to an isolated ground receptacle. The isolated ground receptacle is mounted in a metal box. Along with the circuit conductors, you will pull in ___.

one grounding conductor and connect it to the metal box AND one grounding conductor and connect it to the green screw on the receptacle

Generally, circuit breakers must be ___.

readily accessible

What is not a factor when calculating voltage drop?

size of the conduit

If installed, a surge protective device shall be connected to each ___ conductor.

ungrounded

The secondary of a 300 KVA transformer delivers power to a 180-amp, 3Ø load. This is a 480 — 240 volt Δ-Δ transformer. Primary and secondary conductors are the minimum size required to serve the load. Refer to Scenario 220.53. The secondary OCPD can have a rating no greater than ___ amps.

200

The use of the term SPD is becoming quite common and is addressed in NEC® Article ___.

242

If the resistance to ground of a single driven ground rod exceeds ___ ohms, an additional ground rod must be driven.

25

When ___ touch together, this is a ground fault. I. two ungrounded circuit conductors II. an ungrounded and a grounded circuit conductor III. an ungrounded circuit conductor and the metal conduit

III only

Which of the following conductors can be used in a damp location?

XHH

Section 250.138 permits all the following methods of grounding cord-and-plug-connected equipment, except for ___.

a three- to two-prong attachment plug adapter

An emergency action plan includes ___.

a. procedures to account for all employees after an emergency evacuation b. escape routes c. procedures for those employees who are to operate any critical equipment d. all of these

An emergency action plan should include a list of the ___ of persons who can provide additional information or explanation.

a. titles b. names c. contact information d. all of these (correct)

Any ___, that is/are part of your job duties, must be outlined in an emergency action plan.

rescue and medical duties

An electrical service is grounded (connected to earth) to ___.

stabilize the voltage during normal operation

A grounded circuit conductor shall be permitted to ground noncurrent-carrying metal parts of equipment on the ___ or within the enclosure of the ac service-disconnecting means.

supply side

Refer to Figure 204.5. The conductors at Point I are ___.

taps