New EGC selection table

[mbrooke]

A lot don't think you have to up-size the EGC when you take VD into account, or use the excuse thats what they had on hand hence the larger ungrounded conductors.

 

[don_resqcapt19]

Sure you have the right date there? Likely will be able to purchase a copy in September or October of 2025

With the old ROP/ROC system early November of the code year was the deadline for submission of changes for the next edition. For they last two code cycles they have been using "TerraView" electronic submission system and the deadline has been in September. For the 2023 code, you had to have your PIs submitted by 9/10/2020. I am just assuming that they will continue the early September date for the 2026 code.

 

[kwired]

With the old ROP/ROC system early November of the code year was the deadline for submission of changes for the next edition. For they last two code cycles they have been using "TerraView" electronic submission system and the deadline has been in September. For the 2023 code, you had to have your PIs submitted by 9/10/2020. I am just assuming that they will continue the early September date for the 2026 code.

but you said " PIs for the 2026 code will be due in September of 2026." That edition should already be in distribution and some places using it by then, pretty sure you meant Sept 2023.

 

[don_resqcapt19]

A lot don't think you have to up-size the EGC when you take VD into account, or use the excuse thats what they had on hand hence the larger ungrounded conductors.

That is a rule that does have issue from a physics standpoint. If am required to increase the size of the conductor because of ampacity adjustment and/or ampacity correction rules, I am not required to increase the size of the EGC.
I could have a 150 run where the ampacity adjustments made me use 6 AWG on a circuit where I would be permitted to use 10 AWG and in that case I would not have to increase the size of my EGC...it would still be 10 AWG.
If I take that same circuit and install 6 AWG because I want to, I would have to install a 6 AWG EGC.
The physics of clearing a fault is the same on both circuits as the ampacity corrections and adjustments don't change that.

but you said " PIs for the 2026 code will be due in September of 2026." That edition should already be in distribution and some places using it by then, pretty sure you meant Sept 2023.

yes are correct...I only read what I intend to write, not what I actually write

 

[mbrooke]

That is a rule that does have issue from a physics standpoint. If am required to increase the size of the conductor because of ampacity adjustment and/or ampacity correction rules, I am not required to increase the size of the EGC.
I could have a 150 run where the ampacity adjustments made me use 6 AWG on a circuit where I would be permitted to use 10 AWG and in that case I would not have to increase the size of my EGC...it would still be 10 AWG.
If I take that same circuit and install 6 AWG because I want to, I would have to install a 6 AWG EGC.
The physics of clearing a fault is the same on both circuits as the ampacity corrections and adjustments don't change that.

Right, but not when upsized for length.

You do make a good point though.

 

[romex jockey]

The physics of clearing a fault is the same on both circuits as the ampacity corrections and adjustments don't change that.

why do the 'physics of electricity' not change for an EGC, yet do for any other conductor Don?

~RJ~

 

[kwired]

why do the 'physics of electricity' not change for an EGC, yet do for any other conductor Don?

~RJ~

a short circuit or ground fault is supposed to clear in short time.

Ampacity for normal operation can be for indefinite time.

Small conductor carrying 1000 amps during a fault likely clears the OCPD in under a second, insulation has not really been compromised.

 

[mbrooke]

a short circuit or ground fault is supposed to clear in short time.

Ampacity for normal operation can be for indefinite time.

Small conductor carrying 1000 amps during a fault likely clears the OCPD in under a second, insulation has not really been compromised.

Depends on the length... Nothing in the NEC limits me from a 30 second open.

 

[don_resqcapt19]

why do the 'physics of electricity' not change for an EGC, yet do for any other conductor Don?

~RJ~

That is not what my comment says...read my complete comment. I gave examples of two circuits using the same size conductors and OCPD, yet one requires an increased size EGC and the other does not...that is the code trying to say that the physics change for those two circuits.

 

[romex jockey]

That is not what my comment says...read my complete comment. I gave examples of two circuits using the same size conductors and OCPD, yet one requires an increased size EGC and the other does not...that is the code trying to say that the physics change for those two circuits.

Your post insinuates increasing/decreasing an EGC make no difference in it's performance Don

~RJ~

 

[kwired]

Depends on the length... Nothing in the NEC limits me from a 30 second open.

True, but at same time 1000 amps of fault current on a short length smaller conductor is no longer going to be 1000 amps of fault current for a long length if the size remains the same, and insulation still isn't as compromised as if it were to be allowed to carry the current indefinitely.

 

[mbrooke]

True, but at same time 1000 amps of fault current on a short length smaller conductor is no longer going to be 1000 amps of fault current for a long length if the size remains the same, and insulation still isn't as compromised as if it were to be allowed to carry the current indefinitely.

But your still heating it up, in conduit or cable essembly with current carrying conductors.

If you treated table 250.122 like you did with tap rules, even under engineering supervision, you'd have violations semi often.