Installing electricity in your garden shed can seem like an intimidating task if you've never done it before. However, with proper planning and by following electrical codes, you can safely and legally wire your shed without hiring an electrician.
Understanding the Basics of Wiring a Shed
Before you begin, it's important to understand some key concepts:
-
Electrical service - The main power source coming from your house to the shed. This is typically 120/240V AC power in the US.
-
Circuit breaker panel - The central hub where all the electricity is distributed. This contains circuit breakers that shut off power in case of overload.
-
Wire gauge - The thickness of the copper wires. Thicker wires can handle more current. 12 AWG is typical for 15-20 amp circuits in sheds.
-
Conduit - Tubing that protects and routes the wires. Rigid metal or PVC are common outdoor conduit types.
-
Outlets - Where devices are plugged in. Outdoor covers provide waterproofing.
-
Grounding - System of wires and rods that prevent shocks and stabilize voltage. Critical for safety.
Determining Your Power Needs
The first step is figuring out how much power your shed needs by adding up the wattages of lights and outlets:
-
Lights - LED shop lights are around 25 watts each. Estimate 3-4 lights.
-
Outlets - Standard outdoor outlets are often 15 amps, which provides 1800 watts.
-
Machinery - Consider needs for larger tools like table saws or dust collectors. Check nameplate for wattage.
As an example, a basic 10x12 shed might need:
- 3 LED lights x 25 watts = 75 watts
- 2 outlets x 1800 watts = 3600 watts
So the total is around 3675 watts. This determines the necessary circuit breakers and wire size.
Running the Electrical Service
There are two options for running power from your house panel to the shed:
-
Underground conduit - Provides protection by burying the wires. Requires trenching.
-
Overhead cable - Suspended from poles or the house eaves. Exposed but faster to install.
100 amp, 120/240V service can support most shed needs. Use #2 aluminum or #3 copper wires to handle the load. Install within approved, grounded conduit.
Installing the Circuit Breaker Panel
The circuit breaker panel divides and protects all the branch circuits in your shed.
When selecting a panel, consider:
-
Number of circuits needed - plan for future expansion too.
-
Amperage - match to the main service wire size.
-
Indoor vs. outdoor - outdoor units have weatherproof covers.
For example, a 12-space, 100 amp outdoor panel mounted on the wall provides capacity for plenty of circuits.
Running the Branch Circuits
Next, run wire from the panel to lights, outlets and equipment.
Follow electrical code for:
-
Wire gauge - #12 AWG for 15-20 amp circuits is common.
-
Conduit type - EMT, PVC Schedule 80 are good options.
-
Number of wires - hot, neutral, ground required for most branch circuits.
-
Outlet spacing - outlets every 12 feet or less along walls.
Also consider GFCI protection for outlets near water sources like spigots.
Installing the Lights, Switches and Outlets
You're almost done! Just install:
-
LED light fixtures wired to switches near entry doors. Place lights high on ceiling for best illumination.
-
Outdoor receptacles with in-use covers every 12 feet or less along walls.
-
GFCI outlets within 6 feet of sinks or spigots per code.
-
Junction boxes to hold wires, switches and receptacles. Nail securely to studs.
-
Wall plates that fit flush and cover boxes after painting.
Final Steps for a Safe Electrical Shed
Before enjoying your new powered shed, follow these final safety steps:
-
Label and organize wires inside boxes and panel.
-
Test GFCIs by pushing the "Test" button to ensure they trip.
-
Check for grounding with a multimeter between hot and ground. Should be <0.1 ohms.
-
Inspect all wire connections to confirm tight and corrosion-free.
-
Energize the panel and test lights/outlets. Confirm proper function.
If all checks out, you now have a professional-quality, safely wired shed ready to power! Turn on your favorite radio station and get building.