oven requirements

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JoeNorm

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I'm installing a stand alone single oven. They call it a 4.2KW unit and specify a 30amp breaker. The fixture whip(hard wired) is #12 stranded.

So I am thinking running #10 will be more than adequate but the manual calls for #8. Is there any justification for this?

Not only does it call out #8 but it says #8 solid wire, which I am not sure if I have ever even seen.

I normally defer to manufactures specs like I am supposed to but in this case I am questioning them. Thoughts?
 
JoeNorm said:
I'm installing a stand alone single oven. They call it a 4.2KW unit and specify a 30amp breaker. The fixture whip(hard wired) is #12 stranded.

So I am thinking running #10 will be more than adequate but the manual calls for #8. Is there any justification for this?

Not only does it call out #8 but it says #8 solid wire, which I am not sure if I have ever even seen.

I normally defer to manufactures specs like I am supposed to but in this case I am questioning them. Thoughts?
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The only #8 solid I have ever seen was bare for grounding/bonding use.

Mark
 
Do you have a link to the instructions? The 30 amp circuit is fine. Why they would require #8's for a 30 amp circuit is beyond me. Also the #12 wire in the whip is fine because it typically is a much higher temperature rated wire than THHN and the manufacturer can use conductors smaller than those required by the NEC. Good luck trying to find a cable with #8 solid.
 
Little Bill said:
I was thinking since the resistance (heating elements) were the same you would figure it the same.
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To do that, determine the load's resistance (the constant), then calculate the new current (the result) on the new voltage (the variable).

Remember, a resistive load actually has a fixed resistance, not a fixed power. The rated power is a result of applying a certain voltage.
 
LarryFine said:
To do that, determine the load's resistance (the constant), then calculate the new current (the result) on the new voltage (the variable).

Remember, a resistive load actually has a fixed resistance, not a fixed power. The rated power is a result of applying a certain voltage.
Click to expand...
I'm not sure I would call a heating element a "fixed resistance" value. The resistance goes up as the heat goes up, just like a light bulb. Please tell me if I'm missing something, I probably am.

Mark
 
JoeNorm said:
I'm installing a stand alone single oven. They call it a 4.2KW unit and specify a 30amp breaker. The fixture whip(hard wired) is #12 stranded.

So I am thinking running #10 will be more than adequate but the manual calls for #8. Is there any justification for this?

Not only does it call out #8 but it says #8 solid wire, which I am not sure if I have ever even seen.

I normally defer to manufactures specs like I am supposed to but in this case I am questioning them. Thoughts?
Click to expand...
Is there a UL label? 8 solid in romex or se I have never seen.
 
busman said:
I'm not sure I would call a heating element a "fixed resistance" value. The resistance goes up as the heat goes up, just like a light bulb. Please tell me if I'm missing something, I probably am.
Click to expand...
Compared to cold, I'm sure you're right, but I doubt there's much difference between 240v and 208v.
 
I actually cannot remember the brand right now. To be clear, I already ran #10 so I am choosing to ignore the specs.

I just thought I'd ask here to see if anyone has seen oddball requirements like that.
 
busman said:
I'm not sure I would call a heating element a "fixed resistance" value. The resistance goes up as the heat goes up, just like a light bulb. Please tell me if I'm missing something, I probably am.

Mark
Click to expand...
I think you meant "as the temperature goes up".
You're not missing anything about the physics; they're spot on. But it appears your editor was asleep at the switch.
 
Probably Chinese made. I had an Italian engineer want 5/0 wire to a machine I was installing! Maybe they make 5/0 in Italy, but sure haven’t seen it here! LOL!
 
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