Shed Plans Shed Electrical and Lighting 1 — Questions and Answers
Question 1: What electrical service size is typically sufficient for a basic shed workshop with lights and a few outlets?
- 15-amp, 120V sub-panel
- 60-amp sub-panel (Correct answer)
- 100-amp sub-panel
- 200-amp sub-panel
Correct answer: 60-amp sub-panel
A 60-amp sub-panel is the most common recommendation for a workshop shed, providing enough capacity for lighting, general outlets, and a small air compressor or power tool.
Question 2: What type of wire is required for an underground run from the house to a detached shed?
- Standard 14/2 NM cable
- UF-B (underground feeder) cable or conduit with THWN wire (Correct answer)
- ROMEX run in a trench
- Extension cord rated for outdoor use
Correct answer: UF-B (underground feeder) cable or conduit with THWN wire
UF-B cable is rated for direct burial, or THWN wire pulled through rigid conduit provides the moisture resistance required for underground electrical runs.
Question 3: How deep must a direct-burial electrical cable be buried for a residential shed run?
- 6 inches
- 12 inches (Correct answer)
- 24 inches
- 36 inches
Correct answer: 12 inches
Direct-burial UF-B cable must be buried at least 24 inches deep per NEC 300.5, though conduit allows a shallower 18-inch depth for certain applications.
Question 4: What device is required by code on all outdoor and bathroom circuits in a shed?
- AFCI breaker only
- GFCI (Ground Fault Circuit Interrupter) outlets or breaker (Correct answer)
- Standard 15-amp breaker
- Surge protector
Correct answer: GFCI (Ground Fault Circuit Interrupter) outlets or breaker
GFCI protection is required by the NEC for all outdoor, garage, and damp/wet location receptacles to protect against ground fault electrocution hazards.
Question 5: Which conduit type is recommended for exposed electrical wiring inside a wood-framed shed?
- PVC Schedule 40 conduit
- EMT (electrical metallic tubing) (Correct answer)
- Flexible metal conduit only
- Open wiring with staples
Correct answer: EMT (electrical metallic tubing)
EMT conduit is preferred for exposed interior runs in sheds because it is rigid, durable, and provides a ground path, though PVC is also acceptable indoors.
Question 6: What is the minimum height for a light switch in a shed according to common installation practice?
- 18 inches from floor
- 36 inches from floor
- 48 inches from floor (Correct answer)
- No minimum required
Correct answer: 48 inches from floor
While the NEC does not specify a height, standard practice places light switches at 48 inches (4 feet) from the finished floor, consistent with residential construction norms.
Shed Plans Shed Electrical and Lighting 1
What electrical service size is typically sufficient for a basic shed workshop with lights and a few outlets?