Choose the best answer:
1. Where more than one nominal voltage system exists in a building, which of the following installations is not a color-code requirement for multi-wire branch-circuits installed in the same raceway?
(a) 120V circuits: Black/Red/Blue/White
277V circuits: Brown/Orange/Yellow/Natural gray
(b) 120V circuits: Black/Red/Blue/White
277V circuits: Brown/Orange/Yellow/White with blue stripe
(c) 120V circuits: Black/Red/Blue/White
277V circuits: Black (brown marking tape)/Red (yellow marking tape)/Blue (orange marking tape)/White with black stripe
(d) 120V circuits: Black/Red/Blue/White
277V circuits: Brown/Orange/Yellow/White with green stripe
2. Where a 20A branch-circuit supplies a single bathroom, which of these items cannot be connected to this circuit?
(c) Outside receptacles
(d) Hydromassage tub
3. Which of the following overcurrent protection devices is not allowed to be used for general-purpose branch-circuits?
4. How many small appliance branch-circuits are required for a dwelling's countertops when there are two kitchens?
(c) 5 (
5. Which of the following means of identification isn't allowed for No. 6 or smaller equipment grounding conductor (EGC) used as a branch-circuit?
(a) Black with green marking tape
(b) Continuous green color
(c) Continuous green with yellow stripe.
Answers and discussion
1. (d), Sec. 210-4(d) requires multi-wire branch-circuits to be identified for each ungrounded conductor (based on the voltage). This means of identification is be by separate color coding, marking tape, tagging, spray paint where permitted, or another effective means accepted by the AHJ. This is a means of identification to easily determine each system's voltage. Sec. 200-6(d) requires multi-wire branch-circuits to be identified for each grounded conductor (based on the voltage), identified by white, natural gray, or white with a readily distinguishable different colored stripe (not green) running along the insulation. Note: Check with AHJ on use of natural gray on 277V circuits. Stallcup's Code Loop: 210-4(d), 200-6(d), 200-6(a), and 200-6(b).
2. (c), Sec. 210-11(c)(3), Ex. permits outlets for other equipment within the same bathroom to be connected to this 20A branch-circuit. Outside receptacles are not to be connected to any branch-circuit supplying a bathroom. If a hydromassage tub is connected to this 20A branch-circuit, Sec. 210-23(a) requires fastened-in-place equipment not to exceed 50% of the branch-circuit rating. An individual circuit may be required for the hydromassage tub per the listing and labeling. However, Secs. 110-2 and 110-3(b) will not allow the hydromassage tub to be connected to this 20A branch-circuit supplying the bathroom. Stallcup's Code Loop: 210-11(c)(3), Ex., 210-23(a), 110-2, 110-3(b), and 210-11(c)(3).
3. (c), Secs. 210-3 and 210-23(a) and (b) permits 15A, 20A, 30A, 40A, and 50A overcurrent protection devices to be used for purposes other than individual branch-circuits. A 25A overcurrent protection device is used for individual branch-circuits. Stallcup's Code Loop: 210-3, 210-21(b)(1), 210-21(b)(2), 210-23(a), and 210-23(b).
4. (b), Sec. 210-52(c)(3) requires two small appliance branch-circuits for each kitchen. This requirement prevents using small appliance branch-circuits supplying one kitchen to be extended to another kitchen to serve its required receptacle outlets. This change in the 1999 NEC clarifies that each kitchen (if more than one) needs its own small appliance branch-circuits. Stallcup's Code Loop: 210-52(c)(3), 210-52(c)(1), and 210-11(c)(1).
5. (a), Sec. 210-5(d) refers to Sec. 250-119 permits equipment grounding conductors to be identified by a continuous green color,continuous green color with one or more yellow stripes, or bare. Sec. 250-119(a) permits conductors larger than No. 6 to be identified by using green marking tape to identify equipment-grounding conductors. Stallcup's Code Loop: 210-5(d), 250-119, and 250-119(a).