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Discussion Starter #1
I have an electric stove that's hooked up to a 220 30 amp fuse with number 8 wire. 3 wires and ground. I wanted to move it to an area where I have existing 220 #10 wire ( also 3 wires and ground).

I thought Ok, a 30 amp fuse is rated for #10 wire. Should be fine as long as I have a 30 amp fuse on the line. Which would blow before my #10 wire fried.

But then halfway through I noticed that the stove said 240 volts at 8.8 KW.

A simple calculation using ohm's law: A=W/V

Amps equals watts divided by volts.
so 8800 watts divided by 240 volts equals 36.6 amps.

It was already on a 30 amp fuse, which it never blew. But it seems to be calling for a 40 amp fuse, which I can not safely put on #10 wire.

Anyway, the question is are my calculations correct? And is it Ok AND national code compliant to to use #10 wire and a 30 amp fuse for this stove? Thanks



 

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Range circuit sizing is done by calculations fouund in NEC 220.55 and gets pretty tricky, however 210.19(3) says that any range over 8,750W must be on a minimum of a 40 amp circuit, and your stove is just a hair over that. Your math is indeed correct, but ranges are one of those dedicated circuits where an appliance can draw a certain amount over it's rated breaker limit because it's a non-continuous draw.
 

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Discussion Starter #5
It actually has a 50 amp plug on it. I guess what confused me was seeing that 30 amp breaker on it and then assuming that the last person had done it right, when in fact it probably should have had a 40 or 50 amp on it at it's rated power draw.

Well we all know what happens when we ass-u-me....
I just wished I had looked harder before I spent a day configuring it all. Because I won't do it unless it's safe and correct. And I'm sure my home owners insurance would agree with me.
 

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Discussion Starter #6
And looking a little closer i wonder if the last electrician did it that way on purpose? Because its 100 amp service with breakers for a water heater and dryer as well ( plus the lights and fridge). You'd probably blow the box if you ran it all at full power.
I no longer have the dryer in that box, so I wonder if I should swap out the 30 amp stove breaker with a 40.

I guess it doesn't matter in terms of safety. Too small a fuse would just blow. It's only to big a fuse that's an issue, right?
 

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A 50 amp plug and receptacle are basically standard for ranges regardless of circuit size. 40 amp plugs don't exist and dryers are generally 30, so they go with 50 amp plugs on ranges because they're power hungry and to help prevent people from plugging a range into a 30 amp dryer outlet.
 

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A smaller 30 amp fuse would blow after a while over 30 amps. They have a time curve that could take minutes. During this time you can have heating of the conductors and fuse connections.
 

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Discussion Starter #9 (Edited)
A smaller 30 amp fuse would blow after a while over 30 amps. They have a time curve that could take minutes. During this time you can have heating of the conductors and fuse connections.
Ok. So I should swap out that 30 amp breaker that's hooked up to the #8 wire and a 36 amp stove with a 40 amp breaker. Because I may damage my breaker and possibly the connections in the box. Is what you are saying bobelectric?
 

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The #8 wire and plug are correct for the stove. I can't fathom why they would install 30 amp fuses. Perhaps they didn't have any 40s.
 
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