Gas range

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Jerseydaze

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I have a new modular home that’s roughed for 40amp ranges the customer has decided to go with gas instead.Is there any reason I can’t splice #12s onto the #8 and convert the receptacle ?
 
When I converted from electric to gas I thought about doing just that but decided it would be tacky. So I ran a new circuit and left the old in place. Did the same with the dryer. Maybe some day electric will be cheaper or someone will just hate gas and go back to electric, who knows. But in your case you should be fine.

-Hal
 
This always get me tho: would 250.122(A) require the grounding conductor to also be #8? The conductors arent being upsized for VD, they arent being changed at all, but I've lost that argument/interpretation of 250.122 here before.

8/3 NM has a #10 ground wire.
 
The simple fix

TW0Tk.jpg
 
JFletcher said:
This always get me tho: would 250.122(A) require the grounding conductor to also be #8? The conductors arent being upsized for VD, they arent being changed at all, but I've lost that argument/interpretation of 250.122 here before.

8/3 NM has a #10 ground wire.
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That one is a judgement call IMO. Strictest interpretation - yes EGC needs to be 8 AWG.

NEC doesn't think we are smart enough to figure out if EGC would be sufficient and doesn't allow us to calculate EGC, instead they want to plan for worst case possible and size according to that. I honestly believe even 100 foot circuit the 10 AWG is probably sufficient. More then 100 feet might need to be larger conductor. It is all about (or should be) getting high enough current to flow to operate overcurrent device in a certain amount of time. Conductor resistance is just a part of the real equation of how fast a device will respond.

I've seen 1300 - 1400 feet length of #4 aluminum (including EGC) on 480/277 that didn't blow a 30 amp fuse when ground fault occurred. Just too much resistance in the length and something else failed first.
 
kwired said:
That one is a judgement call IMO. Strictest interpretation - yes EGC needs to be 8 AWG.

NEC doesn't think we are smart enough to figure out if EGC would be sufficient and doesn't allow us to calculate EGC, instead they want to plan for worst case possible and size according to that. I honestly believe even 100 foot circuit the 10 AWG is probably sufficient. More then 100 feet might need to be larger conductor. It is all about (or should be) getting high enough current to flow to operate overcurrent device in a certain amount of time. Conductor resistance is just a part of the real equation of how fast a device will respond.

I've seen 1300 - 1400 feet length of #4 aluminum (including EGC) on 480/277 that didn't blow a 30 amp fuse when ground fault occurred. Just too much resistance in the length and something else failed first.
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My thought is that if the EGC was sufficient for #8 conductors on a 40A breaker, its sufficient for #8 conductors on a 20A breaker. and we're not upsizing the #8 part of the run, we're downsizing to #12 at the end of it and changing the OCPD to a 15 or 20A breaker.

Because #12 ungrounded conductors require a #12 EGC, upsizing to #8 hots requires a proportional increase in the EGC, which would be a #8 as well. But using #8 ungrounded on a 40A circuit means a #10 EGC is fine.

This example is one where the code makes no damned sense at all. I would convert that 240V 40A range receptacle all day long to a 120V 15/20A and not lose a wink of sleep over the ground wire being #10 instead of #8.

Strictest interpretation withstanding tho, Hal has the only viable solution: run a new circuit.

jumper said:
I kinda forgot that, oops.:ashamed1:
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I still dont believe the intent of 250.122 is to require, in a case like what the OP has, one to use a #8 ground over a #10.
 
jumper said:
I agree Fletch but if the inspector wants to red tag, nothing to be done but do the new circuit route. Yes, strict interpretation but the rule is pretty cut and dried.
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True. So, to re-answer the OP's question: if the range is fed by 4 wire NM (8/3), i.e. the ground wire is #10, it's a no-go. If it's another wiring method with a #8 ground, then yes, he can reduce to #12 at the receptacle, change it to a duplex, and change the breaker and call it a day.

Still makes zero sense but that's the "correct" answer.
 
JFletcher said:
True. So, to re-answer the OP's question: if the range is fed by 4 wire NM (8/3), i.e. the ground wire is #10, it's a no-go. If it's another wiring method with a #8 ground, then yes, he can reduce to #12 at the receptacle, change it to a duplex, and change the breaker and call it a day.

Still makes zero sense but that's the "correct" answer.
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Yep, no way around it unfortunately.
 
JFletcher said:
My thought is that if the EGC was sufficient for #8 conductors on a 40A breaker, its sufficient for #8 conductors on a 20A breaker. and we're not upsizing the #8 part of the run, we're downsizing to #12 at the end of it and changing the OCPD to a 15 or 20A breaker.

Because #12 ungrounded conductors require a #12 EGC, upsizing to #8 hots requires a proportional increase in the EGC, which would be a #8 as well. But using #8 ungrounded on a 40A circuit means a #10 EGC is fine.

This example is one where the code makes no damned sense at all. I would convert that 240V 40A range receptacle all day long to a 120V 15/20A and not lose a wink of sleep over the ground wire being #10 instead of #8.

Strictest interpretation withstanding tho, Hal has the only viable solution: run a new circuit.



I still don't believe the intent of 250.122 is to require, in a case like what the OP has, one to use a #8 ground over a #10.
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I agree the intent may not necessarily be to require an 8 AWG ground in this case - but they wrote one rule to fit all situations, and either isn't quite being understood, enforced, etc. or people just don't realize the rule is there, so it hasn't caused enough problems for anyone to submit PI to try to change it.

Like I said upsizing a 20 amp circuit to 8 AWG - the 10 AWG EGC probably is not going to effect performance of OCPD all that much for under 100 feet length. Longer runs it very well could. Available fault current at the start of the circuit also has an impact on real world situation.

NEC just decided proportional increase in EGC was a one size fits all solution.
 
I need a little help here.

Can someone go to the NFPA site, bring up the ROP for 2014, copy and paste 5-199 for me?

I would appreciate it very much. It relates directly to interpreting the section in question.

It is still pdf format, but my ipad is screwy and keeps dropping it.:rant:
 
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