Conductors

What size THWN copper conductors and OCPD are required for an individual branch-circuit to a small processing machine with a nameplate current rating of 38 amps (continuous load)? Answer? What code section?

#8 = 50 amps (Table 310.15 (B)(16)) 38 x 1.25 = 47.5 amps 47.5 amps = 50 amp OCPD Article 310.15 (B)(16) Article 210.19 (A)(1)(a)

Copper and aluminum conductors shall be permitted to be connected in parallel in sizes No. ___________________ or larger. Answer? What code section?

1/0 AWG Article 310.10 (H)

Loads that are continuous shall have their full-load currents increased by percent and this value added to noncontinuous loads at percent. (branch-circuit conductors) Answer? What code section?

125% for continuous loads and 100% for non-continuous loads Article 210.19

What size overcurrent protection device is required for four current-carrying No. 12 THHN copper conductors in a cable? Answer? What code section?

20 x .80 =16 x 1.25 = 20 Article 240.4 (D)(5) also states minimum of 20A Article 310.15 (B)(16) Article 310.15 (B)(3)(a) Article 240.4 (D)(5)

continuous load is where the current in amps can operate for a period of time of _________ hours or more. Answer? What code section?

3 hours or more Article 100

If __________ or more current-carrying conductors are pulled through a raceway or bundled in a cable for a distance greater than _________in., the allowable ampacity of such conductors shall be reduced (derated). Answer? What code section?

4 or more 24 inches Article 310.15 (B)(3)(a)

What is the ampacity rating for four No. 10 THHN copper conductors (three current-carrying) routed through an ambient temperature of 125°F? Answer? What code section?

40 x .76 = 30.4 (4th conductor is not counted as it is not current carrying, only count 3) Article 310.15 (B)(16) Article 310.15 (B)(2)(a)

What size THHN copper conductors (two) and OCPD are required for a branch-circuit with a 6 amp noncontinuous load and 10 amp continuous load, based upon an ambient temperature of 125°F? Answer? What code section?

6 x 1.00 (Non-continous) = 6 10 x 1.25 (Continous) = 12.5 6 amps + 12.5 amps = 18.5 amps 25A = #14 AWG 20A OCPD Article 310.15 (B)(16) Article 240.4 Article 240.6 (A)

Insulated conductors of No. ______ and smaller, when used as grounded conductors, shall have a continuous white or gray insulation. A. 10 B. 8 C. 6 D. 4 Answer? What code section?

C. 6 AWG Article 200.6 (A)

What is the ampacity of a 12 THHN conductor when installed in a location that has an ambient temperature of 45°F A. 20A B. 25A C. 33.25A D. 34.50A Answer? What code section?

D. 34.50A 12 THHN = 30 amps 30 x 1.15 = 34.5 Article 310.15 (B)(16) Article 310.15 (B)(2)(a)

Conductors that are intended for use as ____________________ conductors, whether used as a single conductor or in multiconductor cables, shall be finished to be clearly distinguishable from grounded and grounding conductors Answer? What code section?

ungrounded Article 310.110 (C)

Where installed in raceways, conductors __________ and larger, not specifically permitted or required elsewhere in this Code to be solid, shall be stranded. Answer? What code section?

8 AWG Article 310.106 (C)

What size THHN copper conductors and OCPD are required for a circuit with a calculated load of 80 amp load connected to 60°C terminals? Answer? What code section?

80 x 1.25 = 100 & 85A (60 C) = #3 AWG Article 310.15 (B)(16)

Class 1 are current-carrying when they carry continuously more than __________ percent of their ampacity. A. 10 B. 20 C. 30 D. 50 Answer? What code section?

A. 10 percent Article 725.51 (A)

Conductors listed as suitable for dry locations shall be permitted in damp or wet locations. True or False? What code section?

False Article 310.104 (A)

Where two different ampacities apply to adjacent portion of a circuit, the higher ampacity shall be permitted to be used beyond the point of transition, a distance equal to __________ ft. or __________ percent of the circuit length figured at the higher ampacity. Answer? What code section?

10 feet or 10 % Article 310.15 (A)(2)(Exception)

What is the ampacity rating for eight No. 10 THHN copper conductors (all current-carrying) routed through an ambient temperature of 120°F? Answer? What code section?

40 x .70 = 28 28 x .82 = 22.96 Article 310.15 (B)(16) Article 310.15 (B)(3)(a) Article 310.15 (B)(2)(a)

What is the ampacity rating for four No. 10 THHN copper conductors that are currentcarrying? Answer? What code section?

40 x .80 = 32 Article 310.15(B)(16) Article 310.15 (B)(3)(a)

Solid aluminum conductors 8, 10, and 12 AWG shall be made of an ____________________ electrical grade aluminum alloy conductor material.. Answer? What code section?

AA-8000 Series Article 310.106 (B)

Where the rating of the overcurrent protection device is __________ amps or less, the terminal rating is 60°C if it is not otherwise marked. A. 60 B. 100 C. 150 D. 200 Answer? What code section?

B. 100 amps Article 110.14 (C)(1)

What is the ampacity of a 4 - #6 THWN-2 conductor installed % in. above the roof where the ambient temperature is 900 F A. 24A B. 45.6A C. 33.25A D. 43.50A Answer? What code section?

B. 45.6A #6 THWN-2 = 75 amps (Table 314.15 (B)(16)) 75 amps x 0.80 = 60 amps (Table 310.15 (B)(3)(a)) Add 40F temp for roof adjustment (Table 310.15 (B)(3)(c) 90F + 40F = 130F temp 130F for 90C conductor = 0.76 (Table 310.15 (B)(3)(c)) 60 amps x 0.76 = 45.6 amps

An ampacity derating factor of __________ percent increased foot of depth for all values of RHO shall be utilized if burial depth is greater than specific underground ampacity table or figure A. 3 B. 6 C. 12 D. 18 Answer? What code section?

B. 6 percent Article 310.60 (B)(2)(b)

Conductors with higher temperature ratings, provided the ampacity of such conductors is determined based on the 60°C (140°F) ampacity of the conductor size used. True or False? What code section?

True Article 110.14 (C)(1)(a)(2)

Conductors routed through an ambient temperature greater than 87°F shall be adjusted per correction factors based upon surrounding temperatures. True or False? What code section?

True Article 310.15 (B)(2)(a)

Type XHHW-2 insulated conductors shall not be subject to this ampacity adjustment True or False? What code section?

True Article 310.15 (B)(3)(a)(Exception)

A neutral conductor of a four-wire, three-phase wye system shall be considered currentcarrying when it carries the major portion of the load involving nonlinear related loads. True or False? What code section?

True Article 310.15 (B)(5)(c)

The ungrounded phase conductors shall be identified with any color of insulation or tagging except gray, ____________________ or ____________________. Answer? What code section?

White or Green Article 310.12 Article 200.6