The primary purpose of an electrical sub-panel is to create a place to add more circuits when the main electrical panel is full. Sub-panels you use strictly for this purpose are usually close by the main panel. You might also use a sub-panel when you need power in an area far from the main electrical panel, such as a garage or shed. Installing a sub-panel eliminates the need to run the circuits from the far-off location all the way back to the main panel. For either purpose, electrical sub-panels are fairly easy to install.
Decide where to install the sub-panel. Sub-panels are usually relatively small and do not require much space.
Mount the sub-panel to the wall at its desired location using the screws that came with it. You can either flush-mount or surface-mount the sub-panel.
Return to the main panel. The main panel will contain an unused circuit breaker, which you will need to use for the sub-panel. Make sure to switch this circuit breaker off. If the sub-panel is rated at 60 amps, you will need a circuit breaker that can support at least 60 amps.
Run your wires from the main panel to the new sub-panel. The Renovation Headquarters website shows how. You will need black, white, red and green wires running from the main panel to the sub-panel. The black and red carry power, the white is the neutral, and the green is the ground.
Route the four wires inside the new sub-panel. Strip 1/2 inch of insulation off the end of each wire.
Route the black and red wire to the sub-panel source screws, usually located at the top of the sub-panel, and screw them in, advises licensed electrician David Lincoln. Route the white wire to the sub-panel's neutral bar -- this will be labelled as such -- and screw the wire in place, Lincoln says. Then screw the green wire, which goes to the ground bar in the new sub-panel, into place. You can usually find this at the bottom of the sub-panel; it is also labelled.
Return to the main panel again. Install the black and red wire into the circuit breaker you have designated as the sub-panel power source. Install the white wire to the neutral bar and the green to the ground bar.
Check all the screws for tightness and make sure everything is installed properly. Switch on the circuit breaker to power the sub-panel.
Call a licensed electrician if you are unsure how to complete each step in this process.