What’s the difference between a heavy duty (12 gauge) extension cord and the 12ga wiring inside the walls of a typical north American home? Why can’t you just chop the ends off and use it to wire up an outlet?

Question

What’s the difference between a heavy duty (12 gauge) extension cord and the 12ga wiring inside the walls of a typical north American home? Why can’t you just chop the ends off and use it to wire up an outlet?

In: 250

Answer 1

The other answers are partly right. Stranded wire isn’t preferred for use in walls but that’s not the main issue. Thicker in-wall wires actually are stranded even though it has disadvantages because solid wire would just be too stiff. The correct answer is it doesn’t meet code, but the *reason* it doesn’t need code is primarily the insulation. In-wall insulation needs to last a very long time and handle a certain level of heat as well as being able to bend and be secured in certain ways without breaking. An extension cord might even meet these requirements but it also needs to be specifically tested and certified and clearly marked so an inspector can tell that the right material was used.