Amps/Volts/Watts

luvflyin

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Luvflyin
Clothes Dryer. 240 volt, 4800 watts. What size Breakers do I need? Gauge wire?
 
That dryer draws 20 amps. You can't load a breaker/circuit above 80% of capacity.

10 gauge wire and 30 amp breaker is normal for an electric dryer.
 
Amps = watts / voltage
20amps=4800watts/240volts

As said above, 30 amp breaker and 10 gage wire is standard for a dryer. 20 amps would be the minimum but inrush current is going to be a little more and might trip a fast acting 20amp breaker.
 
Concur with 30A breaker and 10AWG wire, but be advised that you likely need a GFCI breaker. The 2020 NEC requires GFCI protection for 220V dryer circuits in laundry rooms. Other 120V laundry room circuits require dual AFCI/GFCI protection.
 
You can't load a breaker/circuit above 80% of capacity.
Not true. You can't load a breaker over 80% for continuous loads. A dryer is not.

@Half Fast has it right. And Washington State has been on the 2020 NEC since November of 2020.
 
Last edited:
Amps = watts / voltage
20amps=4800watts/240volts

As said above, 30 amp breaker and 10 gage wire is standard for a dryer. 20 amps would be the minimum but inrush current is going to be a little more and might trip a fast acting 20amp breaker.
I had remembered that formula. It was the double breaker thing that was confusing me. I was thinking that two 30’s add up to 60. I know how 240 volt circuits work. Two 120’s out of phase with each other. But now I get it. What I have is the dryer is going to a double 40 now. Old house, many remodels over the years. I’m thinking that circuit used to go to a Stove or something else. Looks like about 8 gauge aluminum wire. It’s pigtailed with wire nuts inside the panel to copper leads to the breaker. I’m thinking I better replace the wire and breaker
 
Not true. You can't load a breaker over 80% for continuous loads. A dryer is not.

@Half Fast has it right. And Washington State has been on the 2020 NEC since November of 2020.
House is in Portland, OR. Built 1910. Last remodel was around 1975. I’m going to sell it.
 
Concur with 30A breaker and 10AWG wire, but be advised that you likely need a GFCI breaker. The 2020 NEC requires GFCI protection for 220V dryer circuits in laundry rooms. Other 120V laundry room circuits require dual AFCI/GFCI protection.
Does that have to be done to existing houses? Nothing new is happening here, no remodel. But it’s going up for sale.
 
Does that have to be done to existing houses? Nothing new is happening here, no remodel. But it’s going up for sale.
Typically, not until a renovation or other material change would force the work to be made to the new code. But once in a while, a municipality could force owners to upgrade X. I got one of those gifts when my village forced homeowners to ensure no storm drainage went to the sewer systems even though it was common practice in the past.
 
Typically, not until a renovation or other material change would force the work to be made to the new code. But once in a while, a municipality could force owners to upgrade X. I got one of those gifts when my village forced homeowners to ensure no storm drainage went to the sewer systems even though it was common practice in the past.
That gutter drainage sewer thing happened in Portland many moons ago. Like the 90’s I think
 
Does that have to be done to existing houses? Nothing new is happening here, no remodel. But it’s going up for sale.

The cost to add in the GFCI is probably negliegable and avoids any possibility of a home inspector flagging during the sale process. Same wiring, just a different breaker (and slightly different connections in the panel).
 
The cost to add in the GFCI is probably negliegable and avoids any possibility of a home inspector flagging during the sale process. Same wiring, just a different breaker (and slightly different connections in the panel).
Good point. Gonna replace it anyway, so I'll throw a few more buck$ at it.
 
Gotta up the wire gauge if sticking with aluminum, but replacing it like you're doing is better. Sometimes the aluminum corrodes and the connection fails. I hate GFCI breakers, they seem to fail randomly just because. But if you're selling the house I would definitely put one in just because of a home inspection.

When I built my house in 2016 the energy code/county wouldn't allow the panel to be inside a coat closet. So its on the outside of the closet wall. Took the panel cover off and hung a picture over it. That's apparently better?
 
You can't put panels in clothes closets or in areas of combustable materials.
 
The cost to add in the GFCI is probably negliegable and avoids any possibility of a home inspector flagging during the sale process. Same wiring, just a different breaker (and slightly different connections in the panel).

Have you priced the difference between a GFCI breaker and a standard breaker?

I don't think the price difference qualifies as negliegable.
 
Have you priced the difference between a GFCI breaker and a standard breaker?

I don't think the price difference qualifies as negliegable.

So I hadn't in a while. GFCI 30A 2P ~$119. 30A 2P ~$15. So a difference of $105. But 15 feet of 10/3 romex is $65. So in the context of the whole job (not knowing how far he's got to run the wire), and compared to having to redo it AFTER the home inspection in today's home market? I stand by negligible. (I admit it was bigger than I expected. Heck, a single pole 20A GFCI is over $50! No wonder everybody uses the outlets to protect circuits. They're around $20.)
 
Yep. They’re also easier to change when they fail.
And by "change", you mean "swap with the working one that's installed a few feet down but happens to be unused, thus saving yourself $20 and a trip to the big box store", right? :)
 
The cost to add in the GFCI is probably negliegable and avoids any possibility of a home inspector flagging during the sale process. Same wiring, just a different breaker (and slightly different connections in the panel).

Except that 30 amp, 220 volt, GFCI breakers can run well over $100 for just the breaker.

Even standard 110 volt 15 amp GFCI breakers are a lot more than a 15 amp GFCI outlet.
 
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