extending 10ga circuit

is it allowable to extend a 10ga, 3wire (with ground), through a junction box? i am renovating a laundry room and i am moving the dryer outlet. the splice would be done in a junction box, left exposed.

or, do i need to take the cable all the way back to the box and start over with a new run?

 

Extending from the junction box is exactly the right thing to do.

The only issue is to make sure that the junction box is large enough for the new wires. If you remove the old receptacle then there will be more than enough room.

-Jon

 

Someone is sure to point out that extending a pre-1996 dryer circuit may be disallowed, since it was wired to an earlier safety code (three wires instead of four). Personally, I feel there is some latitude here depending on how far you move it. Of course, it is always better to update the circuit if feasible.

 

i'm not sure when it was put it since i just bought the house. the existing cable has three wires (white, red, black) and a bare copper ground wire. is that classified as three or four wire?

also, i don't know if it helps to know that it is wired to a double-pole 30amp breaker.

 

When discussing range and dryer circuits, people generally call three wires plus ground a 'four wire' circuit. It gets confusing since (not infrequently) the ground wire doesn't get counted when people describe things (eg. the cable is almost certainly called 10-3 Romex).

In any case, a 4-wire circuit for a dryer is up to current code, and you can extend it with no problems. Previous versions of the code would permit '3-wire' dryer circuits, with two hots and a combined ground/neutral. You can no longer install this type of dryer circuit, but existing circuits would be 'grandfathered' in....until you did upgrades, then they would need to be replaced.

A 220V circuit should always be on a double pole breaker.

-Jon