Gas range

[JFletcher]

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 understand what you are writing. My point is this: If a #10 ground is fine for #8 ungrounded conductors on a 40A OCPD, then it should be fine on a 20A OCPD. If you need a #8 ground with #8 ungrounded conductors for a 20A circuit, you should need them on a 40A circuit too.

I get that the grounds have to be proportionally upsized when the ungrounded conductors are upsized. The problem is that the sizing required by circuit amperage is not a linear progression. #14 thru #10 hots (small conductors per 240.4) require the same size grounds, but #8 and #6 hots require only a #10 ground wire.

If a #10 ground is good (Code acceptable) for a 60A spa circuit utilizing #6 hots (and it is), it should be good for a 15A circuit doing the same. There's *roughly* 4x less fault current that will flow thru a 15A breaker before it trips than a 60A, so there's no way if a #10 is sufficient to carry the fault current for the 60A spa that it's insufficient for a 15A receptacle.

 

[K8MHZ]

"Overload safety feature built in for added protection"

If it were internally fused with a 15A fuse, maybe that's how it's legal?

Specs show 15A non-replaceable fuse.

I have an old one, three prong, in my collection that uses an Edison based fuse. It's a Hubbell or a Leviton, name brand not a hack product.

 

[Dennis Alwon]

The simple fix

Unless it is a 4 wire receptacle..

 

[Dennis Alwon]

If you followed the code then I agree that 250.122 would require a #8 grounding electrode conductor. I have never done that but we usually try and get a different circuit for the gas range

 

[K8MHZ]

Unless it is a 4 wire receptacle..

Look a bit closer, that is for a 4 wire receptacle.

 

[Dennis Alwon]

Look a bit closer, that is for a 4 wire receptacle.

I see.... I wonder how many home owner's have used them with the 40 amp breaker still intact

 

[K8MHZ]

I see.... I wonder how many home owner's have used them with the 40 amp breaker still intact

Why would a HO be compelled to do anything with the breaker?

 

[jumper]

Look at the 2014 ROP. Are we really interpreting 250.122(B) changes correctly?



________________________________________________________________ 5-199 Log #3077 NEC-P05 Final Action: Accept in Principle (250.122(B)) ________________________________________________________________ Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc. Recommendation: Revise as follows:

(B) Increased in Size. Where ungrounded conductors are increased in size from the minimum size that has sufficient ampacity for the intended installation, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors.

Substantiation: This proposal resubmits what would have been the text of the 2011 NEC had CMP 5 reported its action correctly on Proposal 5-290 in that cycle and maintained that position. The inserted language is simple and clear. It is pointless and technically incorrect to require an increase in the minimum size of an equipment grounding conductor, which functions only for a short-time event and can be insulated or bare, just because some condition of use requires the ungrounded conductors to increase in size. Example D3(a) does not make this increase, and it may be necessary to do so if this clarification is not made. Panel Meeting Action: Accept in Principle

Revise the text of 250.122(B) to read as follows:
(B) Increased in Size. Where ungrounded conductors are increased in size
from the minimum size that has sufficient ampacity for the intended installation, wire type equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors.

Panel Statement: The revised text incorporates the text from proposal 5-198. Number Eligible to Vote: 16
Ballot Results: Affirmative: 16

 

[GoldDigger]

I would try the argument that the conductors are larger than the minimum required for the intended installation, but that they have not been "increased in size", instead the required minimum ampacity for the modified installation has been reduced.
A small grammatical and semantic point, but one that might get traction with an individual AHJ.

 

[infinity]

You can tho you'll need a 20A combination AFCI breaker.

NJ doesn't require AFCI for kitchens. :thumbsup:

I agree you need a #8 egc.

 

[LarryFine]

Okay, guys, here's the solution: cut and abandon the #10 EGC and use the three #8s. Color one white and one green at both ends. Sue me for improper factory coloring.

I agree that the logic of asserting that this use is not a case of up-sizing, but one of down-using, also is sound. An inspector should have the authority to accept it this way.

 

[jumper]

Okay, guys, here's the solution: cut and abandon the #10 EGC and use the three #8s. Color one white and one green at both ends. Sue me for improper factory coloring.

I agree that the logic of asserting that this use is not a case of up-sizing, but one of down-using, also is sound. An inspector should have the authority to accept it this way.

That would make too much sense, never fly.

 

[kwired]

Okay, guys, here's the solution: cut and abandon the #10 EGC and use the three #8s. Color one white and one green at both ends. Sue me for improper factory coloring.

I agree that the logic of asserting that this use is not a case of up-sizing, but one of down-using, also is sound. An inspector should have the authority to accept it this way.

I say unless it is a really long circuit the #10 EGC is probably more then sufficient, NEC just went the simple route when it comes to determining minimum size and we actually need more copper then necessary in many cases.

As I mentioned earlier, I see it a lot with irrigation applications where we have really long circuit runs and even have same size EGC as ungrounded conductors - they often blow up a component before it will blow a fuse when you have such a long run, conductor resistance is too current limiting to take out the fuse fast enough. And of course everybody installs RK5 fuses because that is popular and cost least even though something else may be more appropriate.

1/4 mile center pivot - you very well have ~1400 feet of supply conductor to the center pivot. If only powering the pivot it will only be #4 or maybe #2 aluminum. If you are also supplying an electric well you may get quite a bit larger conductor depending on HP of well. Fuse holders will be 30 amp but the machine may specify anywhere from 15-25 amp fuses as typical. Farmers replace everything with 30's once the originals blow. Now have a fault at the last segment of that 1/4 mile pivot and you have an additional circuit length of ~1300', usually 10 AWG is what these systems use for the main power circuit that runs entire length of system. A lot of line to develop current limiting resistance and make that fault last a long time. Where in many industrial plants similar fault condition has less resistance between fault and the source and fault current is high enough you get much faster response time out of overcurrent protection devices.

 

[winnie]

I see.... I wonder how many home owner's have used them with the 40 amp breaker still intact

According to the description of the device, it has a built in non-replaceable fuse, suggesting that the original breaker can stay in place.

Similar adapters are available without a fuse, in which case the 40A (or 50A) breaker would IMHO be a significant problem:
https://www.amazon.com/AC-WORKS-AD1450520-Generator-Household/dp/B077MTF8QF

I wonder if installing something like this: https://www.amazon.com/Bussman-BP-SRU-Fuse-Cover/dp/B00004WA3I would also be an option.

This particular thread is quite timely for me. We have an electric range being replaced with gas in a couple of weeks. Leaving the existing range circuit unmodified is quite an attractive option.

-Jon

 

[texie]

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.

It is things like this that illustrate the problem with prescriptive codes VS performance based codes. On the other hand, performance based codes require a higher level of skill to practice. Prescriptive codes attempt to cover all scenarios but it does not work in all cases as shown in this example. This is where an inspector should apply some sound judgment and experience but sadly this does not seem to usually be the case today.