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Old 08-08-2008, 02:10 PM   #1
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Wiring v/s amperage


Here's my dilemma, I am replacing my good old 15 year old electric cooktop with a new Hybrid electric/induction cooktop. My current breaker is 30 amps and I assume my wire is #10.
The recommended rating for the new cooktop is 40 amps per the catalogue, but when I called the maufacturer support line , they said I am OK with 30 amps.
Total wattage if I add all 4 elements is 8900 watts (that is if all is used at the same time at max power I assume) divide by 240v that gives me 37 amps, am I right so far?
Questions is what will/can happen if I leave my circuit as is, that is 30 amps breaker and #10 wiring. Any risk of fire? Or will the breaker simply pop when all elements are at full power.
As far as I know , it is quite improbable that my wife willbe using them all 4 at full blast.

Changing the wiring to # 8 is an option but quite a painful task, so what to do???

Help me decide!!

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Old 08-08-2008, 02:31 PM   #2
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Wiring v/s amperage


Simply adding up the elements is not the answer.

Post the actual UNIT wattage (or amperage) and we can go from there.

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Old 08-08-2008, 05:45 PM   #3
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Wiring v/s amperage


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Originally Posted by Droptine View Post
My current breaker is 30 amps and I assume my wire is #10.
The recommended rating for the new cooktop is 40 amps per the catalogue, but when I called the maufacturer support line , they said I am OK with 30 amps.
Total wattage if I add all 4 elements is 8900 watts
Questions is what will/can happen if I leave my circuit as is, that is 30 amps breaker and #10 wiring. Any risk of fire? Or will the breaker simply pop when all elements are at full power.
As far as I know , it is quite improbable that my wife willbe using them all 4 at full blast.
Changing the wiring to # 8 is an option but quite a painful task, so what to do???
The rate of chemical reactions, including the aging of materials, doubles for every 10C rise in temperature.
If the insulation of your #10 wire sees 60C when it is carrying 30A,
and if the insulation sees 90C during the time it carries 40A,
then the insulation will be aging at 2x2x2=8x the normal rate during the time it carries 40A.

The cooktop people have got to know this.

I'm wondering if they are willing to put this 30A/40A stuff in writing; stuff said over the phone by manus doesn't count for much.

And if your wire insulation does fail before its time who would connect the event of buying a cooktop with insulation failing?
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Old 08-08-2008, 05:56 PM   #4
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Wiring v/s amperage


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Originally Posted by Yoyizit View Post
The rate of chemical reactions, including the aging of materials, doubles for every 10C rise in temperature.
If the insulation of your #10 wire sees 60C when it is carrying 30A,
and if the insulation sees 90C during the time it carries 40A,
then the insulation will be aging at 2x2x2=8x the normal rate during the time it carries 40A.

The cooktop people have got to know this.

I'm wondering if they are willing to put this 30A/40A stuff in writing; stuff said over the phone by manus doesn't count for much.

And if your wire insulation does fail before its time who would connect the event of buying a cooktop with insulation failing?
Man, I always look forward to your posts...
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Old 08-08-2008, 06:01 PM   #5
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Wiring v/s amperage


Yoyizit;
I don't think he has any intention of using the #10 wire at 40A. What I understand is that he is asking whether or not he could 'get away' with keeping the 30A and #10 for the new cooktop.

If I were doing the install, I would go by mfr specs and change the wiring/breaker as required.
I suppose it is possible to squeak through most days with an under-powered feed, but eventually there will come a time when the breaker will keep tripping, and he will decide that it was a mistake to keep the old wiring/breaker.

Whether or not it would pass inspection as-is, is another story.
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Old 08-08-2008, 06:53 PM   #6
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Wiring v/s amperage


Quote:
Originally Posted by Yoyizit View Post
The rate of chemical reactions, including the aging of materials, doubles for every 10C rise in temperature.
If the insulation of your #10 wire sees 60C when it is carrying 30A,
and if the insulation sees 90C during the time it carries 40A,
then the insulation will be aging at 2x2x2=8x the normal rate during the time it carries 40A.
WHAT does this have to do with ANYTHING?????????


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Originally Posted by Yoyizit View Post
The cooktop people have got to know this.
I seriously doubt it.



Man, do you EVER talk or write like a normal person instead of an engineer?
Why is it engineers always have to show how smart they are???

You must be a barrel of fun at parties.


<Sorry for the rant folks. This has been building up for a while now.>
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Old 08-08-2008, 06:58 PM   #7
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Wiring v/s amperage


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Yoyizit;
If I were doing the install, I would go by mfr specs and change the wiring/breaker as required.
Could we take this a bit further, please (I'm involved with an electrical upgrade to a 100 year old home and am planning on installing an electric countertop range, so I could use the info)?

The electrician at the hardware store says a 50 amp 240-V circuit is needed for a 4 burner electric stove with an oven, so it seems a 40 amp circuit would be adequate for a countertop range (assuming a 4 burner unit, I realize a 5 or 6 burner unit would require larger wires)?

What I'm hoping for here is a brief expanation of how many amps wires of various sizes can handle. My most recent project involved use of 60 amp 240-V breakers and required 6-3 w/ground copper wire--52 feet of which cost $150+ . It stands to reason that lower amp circuits could use smaller wiring, so would an 8-3 work for a 50 amp circuit? It appears that 10 gauge is too small for 40 amps, so where is the "break point"--what gauge would be necessary for a 40 amp circuit?

TIA for whatever information you can provide to help me clear up this confusion!

Dugly

Last edited by YerDugliness; 08-08-2008 at 07:02 PM.
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Old 08-08-2008, 07:18 PM   #8
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Wiring v/s amperage


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Originally Posted by Speedy Petey View Post
WHAT does this have to do with ANYTHING?????????
I seriously doubt it.
Man, do you EVER talk or write like a normal person instead of an engineer?
Why is it engineers always have to show how smart they are???
You must be a barrel of fun at parties.
<Sorry for the rant folks. This has been building up for a while now.>
Can't help ya' with the normal stuff; sorry. . .


party hardy, Petey. . .
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Old 08-08-2008, 07:32 PM   #9
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Wiring v/s amperage


Yeah, I guess not.


Seth Justman wrote that song about my ex-girlfriend BTW.
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Answers based on the 2008 & 2011 NEC.
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Old 08-09-2008, 11:39 AM   #10
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Originally Posted by YerDugliness View Post

What I'm hoping for here is a brief expanation of how many amps wires of various sizes can handle. My most recent project involved use of 60 amp 240-V breakers and required 6-3 w/ground copper wire--52 feet of which cost $150+ . It stands to reason that lower amp circuits could use smaller wiring, so would an 8-3 work for a 50 amp circuit? It appears that 10 gauge is too small for 40 amps, so where is the "break point"--what gauge would be necessary for a 40 amp circuit?

TIA for whatever information you can provide to help me clear up this confusion!

Dugly
Try this calculator. I like it, because it takes into consideration not only current and voltage, but length of the run.

http://www.csgnetwork.com/wiresizecalc.html


FW
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Old 08-09-2008, 11:41 AM   #11
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Can't help ya' with the normal stuff; sorry. . .


party hardy, Petey. . .
What's with the link to J. Geils video?

FW
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Old 08-09-2008, 01:19 PM   #12
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What's with the link to J. Geils video?
Distraction?
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Old 08-10-2008, 10:10 AM   #13
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Man, I always look forward to your posts...
Thank you, Mr. 75.
Some of them are fun to write, with others I'm jus' messin' wit' ya'.
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Old 08-10-2008, 11:28 AM   #14
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Wiring v/s amperage


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Originally Posted by Speedy Petey View Post
WHAT does this have to do with ANYTHING?????????



I seriously doubt it.



Man, do you EVER talk or write like a normal person instead of an engineer?
Why is it engineers always have to show how smart they are???

You must be a barrel of fun at parties.


<Sorry for the rant folks. This has been building up for a while now.>
Speedy. I have asked this guy to go to the professional sites with no success. Thanks for the rant. Saved me from doing it.
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Old 08-10-2008, 01:33 PM   #15
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Speedy. I have asked this guy to go to the professional sites with no success. Thanks for the rant. Saved me from doing it.

(Ignore the video)

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