Chapter 12 Branch Circuits and Feeders 149
Copyright Goodheart-Willcox Co., Inc.
(Continued on the following page.)
NEC NOTE 410.14
Chain-supported fixtures used in a show window
shall be permitted to be externally wired. No other
externally wired fixtures shall be used.
Sample Problem 12-3
Problem: A department store has two lighted show
windows, one 25′ long and the other 20′ long. What
are the branch-circuit requirements for the show-
window load?
Solution: Compute the load based on linear feet of
show window:
Total length = 25′ + 20′
= 45′
Show-window load = 45′ × 200 VA/ft
= 9000 VA
The lighting is a continuous load, so the show-
window load is multiplied by 1.25 to determine the
circuit load requirements:
Circuit requirements = 9000 VA × 1.25
= 11,250 VA
The circuits supplying power for the show-window
lighting must have a minimum capacity of 11,250
volt-amperes.
In addition, receptacles are required for every 12′ of
show window. A total of five receptacles (two for
the 20′ window and three for the 25′ window) are
needed. The receptacle load can then be computed:
5 × 180 VA = 900 VA
Total load = 11,250 VA + 900 VA
= 12,150 VA
Track lighting
Track lighting is often used in commercial buildings for
accent lighting. It is discussed in Part XV of Article 410 of
the Code. The minimum load for track lighting is 150 volt-
amperes for every 2′ of track. To compute the track lighting
load requirements, simply determine the total length of track
lighting, divide by two, and multiply by 150 volt-amperes.
NEC NOTE 410.2
Lighting track is a manufactured assembly
designed to support and energize luminaires (lighting
fixtures) that are capable of being readily repositioned
on the track. Its length can be altered by addition or
subtraction of sections of track.
Sample Problem 12-4
Problem: Determine the track lighting load for a
22′ long section of track.
Solution: Every 2′ requires 150 volt-amperes, so
the length (in feet) is divided by 2′, and then multi-
plied by 150 volt-amperes:
Track lighting load = × 150 VA
length
2′
= × 150 VA
22′
2′
=1650 VA
If this is a continuous load, the circuit requirements
would also include a 1.25 factor.
Sign and outline lighting
Sign and outline lighting is discussed in Article 600
of the Code. A structure must have at least one circuit
exclusively used to supply sign or outline lighting. The
circuit must be designed for a minimum load of 1200
volt-amperes.
Sign and outline lighting loads are considered contin-
uous loads. Therefore, if the rating of the sign and outline
fixtures is greater than 960 volt-amperes (1200 × 0.8 = 960),
the circuit will be greater than 1200 volt-amperes.
Sample Problem 12-5
Problem: A hardware store measures 80′ × 120′. A
portion of the building (80′ × 40′) is used for
storage. The remainder of the building is used as a
showroom. There is a total of 45′ of show windows,
and there is one outdoor sign. What is the total
lighting load for this building?
25′
20′
80′
80′
Storage area
40′