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Tuesday, November 3, 2020
Question:
Greetings,
I am a homeowner trying to get permits. How do I calculate service load? What is a line drawing for service equipment? Thanks for your help.
Allen Lederman
A
Answer:
Hello Allen,
We will advise as to where the information can be found in the National Electrical Code. A single line drawing shows the service, feeders, and branch circuits, usually in a line diagram showing conductors sizes, raceways sizes, grounding diagrams, and often panel schedules identifying the branch circuits and feeders. Article 220 of the NEC provides the specific rules related to calculating a service size for a single-family dwelling. There are examples in Annex D that can be very helpful in developing the calculated load to size the feeder and service loads. See Examples D1(a), D(1)(b), D(2)(a), D(2)(b) and D(2)(c). The process can be a bit too much for someone that does not have an electrical trade background and experience. To that end, recommended to hire a qualified electrical contractor to assist in this process, and perhaps with the process of performing the electrical wiring of the dwelling. This may be a requirement in the jurisdiction where this construction is taking place. Check the requirements of the local building department.