Shed Plans Shed Electrical and Lighting 2 — Questions and Answers
Question 1: What breaker size is appropriate for a 20-amp general-purpose outlet circuit in a shed?
- 15-amp breaker
- 20-amp breaker (Correct answer)
- 30-amp breaker
- 40-amp breaker
Correct answer: 20-amp breaker
A 20-amp circuit requires a 20-amp breaker and must use 12 AWG wire; a 15-amp breaker would be undersized and trip frequently under workshop loads.
Question 2: Why is a separate sub-panel required in a detached shed rather than just running circuits from the house panel?
- It is not required; it is optional
- A sub-panel provides local disconnecting means, allows circuit expansion, and reduces voltage drop over long runs (Correct answer)
- Sub-panels are cheaper than running wire
- Building codes prohibit direct feeds to sheds
Correct answer: A sub-panel provides local disconnecting means, allows circuit expansion, and reduces voltage drop over long runs
A sub-panel in the shed provides a local disconnect, reduces voltage drop on long feeder runs, and allows multiple circuits without routing each one all the way back to the house.
Question 3: Which wire gauge is required for a 20-amp, 120V circuit in a shed?
- 14 AWG
- 12 AWG (Correct answer)
- 10 AWG
- 8 AWG
Correct answer: 12 AWG
12 AWG copper wire is required for 20-amp circuits; 14 AWG is only rated for 15-amp circuits and would be a code violation on a 20-amp breaker.
Question 4: What is the maximum number of outlets allowed on a 20-amp, 120V circuit in a workshop shed?
- 4 outlets
- 8 outlets
- 13 outlets (per NEC 180VA per device rule) (Correct answer)
- No limit
Correct answer: 13 outlets (per NEC 180VA per device rule)
The NEC calculates 180VA per receptacle, and at 120V a 20-amp circuit provides 2,400VA, allowing approximately 13 receptacles, though practical workshop design uses fewer to avoid overloads.
Question 5: What type of lighting is most energy-efficient for a shed workshop?
- Incandescent shop lights
- T12 fluorescent fixtures
- LED shop lights (Correct answer)
- Halogen flood lights
Correct answer: LED shop lights
LED shop lights consume 50–70% less energy than fluorescent or incandescent equivalents and produce more lumens per watt with no warm-up time in cold weather.
Question 6: What gauge wire is used for a 240V, 30-amp circuit feeding a large air compressor or table saw in a shed?
- 12 AWG
- 10 AWG (Correct answer)
- 8 AWG
- 6 AWG
Correct answer: 10 AWG
10 AWG wire is rated for 30-amp circuits at 240V; using a smaller gauge would create a fire hazard from overheating under sustained load.
Shed Plans Shed Electrical and Lighting 2
What breaker size is appropriate for a 20-amp general-purpose outlet circuit in a shed?