A home or workshop never seems to have enough electrical circuits for the many things that routinely require a spare outlet. Adding extra circuits to an existing fuse box can increase the availability of electrical sockets. All the parts needed to install additional power outlet circuits can be obtained generally at a single home improvement or hardware store.
Disconnect the main electrical power to the fuse box. Once power is removed, test the circuits within the fuse box with a volt-ohm meter to ensure no electrical power is present.
Remove the front cover from the fuse box by unscrewing the fasteners on each of the four corners. Set the cover aside.
Locate the unused lug in the fuse box to which the additional line will be added. Remove one of the knockouts adjacent to the spare lug and located in the metal exterior of the fuse box. This opening will be used to route the new wire into the fuse box for installation.
Install the cable gland on the new wire to be routed into the box with the threaded end facing the fuse box. Route the new 12 conductor electrical wire through the opening and pull in at least 24 inches of slack to ensure enough extra wire to accommodate the hookup.
Strip back the new electrical wire approximately 8 to 12 inches by cutting back the outer plastic sheath to expose the white, black and bare (ground) wires. With each of the three wires exposed, use wire strippers to strip approximately 1/2 inch of wire insulation off each of the three wires. The new line is now ready to be connected to the fuse box.
Connect the ground wire to the grounding bar located along the inside edge of the fuse box. The ground bar can be identified by the other bare copper grounds attached to it.
Connect the white (neutral) wire to the neutral bar along the opposite inside edge of the fuse box. The neutral bar can be identified by the other white coloured neutral wires connected to it.
Connect the black (hot) wire to the spare lug located in the fuse box and tighten each connection with the screwdriver.
Install the fuse box cover onto the fuse box and tighten the four fasteners located on each of the four corners of the fuse box.
Route the newly installed electrical wire from the fuse box to the desired location for the additional plug outlets or lights. Cable routing can be through either the attic or the crawl space. The new fuse box line has now been added and is ready to connect to the new outlets or lights as desired.
A common lighting circuit added to a fuse box should be rated for 15 amps and requires a 15 amp fuse.
Always double check to ensure electrical power has been turned off before beginning any work or repairs on electrical devices or boxes.