Master Electrician

When calculating the maximum number of conductors permitted in a conduit or tubing, all of the same size, the next higher whole number shall be used to determine the maximum number of conductors permitted when the calculation results in a decimal of ___ or higher.

.8

Determine the cross sectional area in square inches for the following combinations of copper conductors: 4-#8 AWG, THHN; 8-#12 AWG, RHW; 6 - #10 AWG, XHHW:

0.5746 SI

What size EMT raceway is required for 24, AWG #6 THHN?

1 1/2"

According to Table 8 of the NEC and assuming solid uncoated copper conductor; cross-sectional area of 10,380 CM; resistance of 12.6 Ω/circular mill-foot (KF), calculate the conductors resistance at 75 degrees C. ("R" is resistance in Ohms, "L" is the length of the conductor. Use the formula: R=KL/CM.)

1.2 Ohm/1000 ft.

According to the NEC, a 1 1/2" nipple with three conductors can be filled to an area of ____ square inches.

1.224

What size RMC nipple (18" long) is required for 24, AWG #8 THHN?

1.25"

What is the internal diameter of a 1 1/4" liquid tight, flexible non metallic conduit (type LFNC-A)?

1.395"

The cross sectional area of a conductor is compared to a conductor that is four times its area. What is the approximate resistance of the larger conductor compared to the smaller?

1/4 resistance

A compressor motor is rated 1HP, 115V, 16 amps. It is connected to a receptacle providing 120 volts with a 100' extension cord. Due to the load conditions, the maximum voltage drop allowed during starting lockedrotor condition is 30% of motor voltage rating. Using 96 amps for locked-rotor current. Resistance equals impendence. Use resistance values in Table 8 & 9. What is the minimum size of uncoated copper?

10 AWG

A 1500 square foot dwelling has a 10kw range and a 5.5 kw dryer. According to NEC, what minimum size over current device is required?

100 amp

Common voltages for a residence are:

120/240

According to the National Electrical Code, the minimum size TW copper conductor for a 5 HP, 3 phase, 230 volt, squirrel cage motor started at full voltage shall not be less than # ___ AWG.

14

The circular mil area of a #18 AWG would be ___ CMILS for solid or stranded.

1620

A 2" conduit no more than ___ in length connecting a gutter and a switch case may have conductor fill of 60% of the internal cross sectional area.

24"

How many AWG #12 THHN conductors are allowed in a 1" RMC?

26 #12 THHN conductors

Five conductors, in a 12" nipple of rigid metal conduit, has a total cross sectional area of 2.5 square inches. What is the minimum trade size conduit?

3"

Using the information in the National Electrical Code, table 8, calculate the total resistance of 495' of uncoated, 18 AWG, stranded, copper.

3.85 to 3.93 ohms

How many AWG #12 THHN conductors are allowed in a 1" RMC nipple?

35 wires

The cross-sectional area of a conductor is decreased by a factor of 4. What is the new conductor's resistance?

4 times resistance

Eighteen, 250 KCMIL, THWN copper conductors are in a rigid metal conduit nipple. What is the minimum diameter in inches permitted by for the conduit? Assume that the conductors are not lead covered and the nipple is 1' in length.

5"

Determine the general lighting and appliance load requirements for a multifamily dwelling unit: 40 apartments 800 sf each 2 banks of meters of 20 each, and individual subfeeders to each apartment. 20 apartments have electric ranges; these apartments (with ranges) are evenly divided, 10 on each meter bank; the ranges are 9 kw each. Service is 120/240 volts. The general lighting load and small appliance load for each apartment would be:

5400 VA

Using Table 4 and Table 5 of the NEC, compute the maximum number of # 10 AWG, Type THHN, copper conductors allowed in 32' run of 1/2" "IMC".

6

A new 4000 SF residence would have a minimum net computed feeder load, after derating for the general lighting, of ___ VA.

6150 VA

The circular mil area of a number 12 conductor is ____.

6530

How many #12 RHW copper conductors (with outer covering) can be placed in a 1" EMT conduit?

9

What size load is required to service a residence 1100 sq.ft. 1-10 kw range 1-electric dryer 1-6kw hot water heater no A/C or Heat Single phase 240 V. Use the standard method.

99

Compute the net load for a residence using the following data: 1.1100 SF living area 2. Service 120/240 single phase 3. 10Kw range 4. Laundry 5. 240 Volt clothes dryer 6. Water heater 240 volt 6K

99 amps

The number of #12 THW conductors allowed in a 3/4" conduit will be more than the number of #12 TW conductors allowed in a 3/4" conduit.

False

A hoistway in which an elevator is designed to operate can be all of these except:

any stairway

A branch circuit, consisting of two or more ungrounded conductors that have a potential difference between them, and a grounded conductor that has equal potential difference between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system, is ____.

multi-wire