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Wire and breaker size for old clothes dryer

bergsteiger1's picture

Someone gave me an old but working Kenmore clothes dryer and I would like to hook it up, since using a clothesline is getting old.

My house has a 4 wire receptacle and the wire size of the red, white and black conductors is #10.  I did not measure the ground but it looked a bit smaller, possibly #12.  There is no breaker in my panel for this circuit.

I checked the circuit breaker that this dryer was attached to and it was a 30A, double-pole.  Can anyone tell me if there is a chart somewhere that would specify if you can use a 30A breaker with #10 wire?

Also the dryer has an old-style 3 conductor pigtail on the back.  I figure I need to either buy a 4 wire pigtail or replace my receptacle with a 3-hole receptacle.  I haven't opened the back of the dryer yet, but I am wondering if there will be a neutral and ground in there that is strapped together that I would need to separate if I want to use a new four wire pigtail.  Does anyone have any suggestions?

 

Thanks a lot.

The odds are fairly good that (post #207391, reply #1 of 6)

The odds are fairly good that if you open the back of the dryer there will be terminals for separate neutral & ground with a jumper between them.

If you Google "ampacity" you will find several sites that give you amp capacity for different wire sizes.  Just be sure to use the figures for a multi-wire cable vs loose conductors in a conduit.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Wire and breaker size for old clothes dryer (post #207391, reply #2 of 6)

It looks like a 30A breaker is what I need.  Thanks Dan.  

wire size chart (post #207391, reply #3 of 6)

bergsteiger1 wrote:

  Can anyone tell me if there is a chart somewhere that would specify if you can use a 30A breaker with #10 wire?

Thanks a lot.

 

This is from NEC article 240.4(D), the one that is most commonly applied to residential installations. 

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

(3) 14 AWG Copper. 15 amperes
(4) 12 AWG Aluminum and Copper-Clad Aluminum. 15 amperes
(5) 12 AWG Copper. 20 amperes
(6) 10 AWG Aluminum and Copper-Clad Aluminum. 25 amperes
(7) 10 AWG Copper. 30 amperes

Greg

Dryer wiring (post #207391, reply #4 of 6)

Thanks a lot, Greg.

As somewhat already stated, (post #207391, reply #5 of 6)

As somewhat already stated, 30 ampere is correct for #10 copper. Do not change the receptacle. a 4-prong receptacle for dryers has been code since I believe the 1996 NEC. I believe when you buy a new 4-prong cord you will get instructions showing the proper installation. The neutral should be isolated from the ground.

Wire and breaker size for old clothes dryer (post #207391, reply #6 of 6)

I went ahead and bought the four wire pigtail.  Thanks for the advice.