How to lengthen a short power cord in a distribution box
The wire must be able to come out beyond the surface of the box at least 3". You will need to reroute these cables to a different junction box somewhere the wiring is able reach with the needed spare length inside the box. Before you reach for a clumsy extension cord, consider a more permanent fix: extending electrical wire exactly where you need it. So, what happens when you go to change a device and the wires are just too short? There are generally two ways to fix this: Sometimes you can loosen the box connector at the back of the box and pull more wire out. If you have an electrical box with wiring that is too short to make electrical connections to outlets, switches or even another junction box, you will need to add 'pigtails' to the wiring in order to lengthen the wiring so you can use it.
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