What's the point of full size EGC for an extension cord with GFCI?

kwired said:
Only if the ungrounded conductors are also 10 AWG. If they are 12 AWG the EGC doesn't need to be any larger than the ungrounded conductors.
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Right again, I see it now 250.122 (E) flexible cord and fixture wire it has to be the same size as the ungrounded conductors if its 10 AWG or smaller. If the ungrounded conductors in the cord are larger than 10 AWG they can follow the table.
kwired said:
Of course overcurrent protection for the 5/20R receptacles here is another thing,
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Yeah thats interesting, 210 covers branch circuits which in my mind is permanent building wiring that ends at an 'outlet'.
So a 10 AWG cord with a L14-30 cord cap and 5-20's on the end it would not really fall under Article 210 of the NEC when plugged into a portable generator. Arguably code would not apply at all unless a OSHA or safety inspector was the AHJ and it fell under a article in the 500's that covers portable cords like 520, 525, 590 etc

kwired said:
and good chance the EGC is floating at the generator anyway so all the EGC does is tie the grounding pins of the receptacle to the generator frame, it will almost never be needed to clear a ground fault
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For a portable generator the frame should be bonded at the factory to one of the leads designated as a 'grounded' conductor even if its not connected to earth. Though I have seen people un-bond them when using them as a home backup.
 
tortuga said:
For a portable generator the frame should be bonded at the factory to one of the leads designated as a 'grounded' conductor even if its not connected to earth. Though I have seen people un-bond them when using them as a home backup.
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Most I have encountered are usually not bonded, and in more recent years even have labeling that states they are not bonded.
 
tortuga said:
Yeah I think your right since Article 250 mentions flexible cords in several places.

Also I guess a manufacturer can never know what the branch circuit OCPD of a cord is.
A cord under the NEC is really a kind of 'tap' in a sense.
I see these Y adapters that go from a 30A on the generator to four 20A cord caps,
I am sure they are intended for just generators but I have seen them used creatively.
so any cords plugged into this are on a 30A breaker; then 250.122 will not line up as it would need a 10 EGC;

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I believe the more prevalent cord incidents involve the use of 16/2 or 16/3 multi tap cords with high load items that run for extended durations such as large window A/C or space heaters and often in conjunction with running under the rug. 20A circuits are allowed to have 15A receptacles.

You could plug in a 1500W space heater and a 1,000W oil filled heater. It has three receptacles on the end. With the voltage drop, it would be below 2,500W but perhaps 2,200-2,400W range and would hold indefinitely on a 20A circuit with no other load.

1745245648686.png
 
Flicker Index said:
If the cord set has a permanent inline GFCI that can not be removed without cutting it, why couldn't we have something like 10/2 +16/1 or 12/2+16/1?

Cord sets are not intended for permanent installation and having a full size EGC essentially capable of indefinitely serving as "neutral" through a ground fault into case seems silly. Since you can buy 16 AWG extension cords, 16AWG copper or perhaps 16 CuAl clad would seem adequate for mechanical strength purpose while serving enough conductivity to allow GFCI to work.

The reduced weight without compromising on performance is a big plus.
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Interesting thought, and you're right that GFCI protection changes the game a bit. However, full-size EGCs are still required mainly due to code compliance (like NEC) and safety redundancy. GFCIs trip quickly, but in rare edge cases—like a failed GFCI or if it's bypassed—the EGC becomes the last line of defense.

Also, full-size grounds ensure low impedance paths back to the source during faults, which helps breakers trip fast in non-GFCI scenarios too. Even though it might seem overbuilt, it’s really about covering all possible failure modes, especially since extension cords are so often misused.

But yeah, from a pure engineering standpoint, I see your point—there's probably room for weight and material optimization with more nuanced standards.
 
LaurenceRedgrave13 said:
Interesting thought, and you're right that GFCI protection changes the game a bit. However, full-size EGCs are still required mainly due to code compliance (like NEC) and safety redundancy. GFCIs trip quickly, but in rare edge cases—like a failed GFCI or if it's bypassed—the EGC becomes the last line of defense.

Also, full-size grounds ensure low impedance paths back to the source during faults, which helps breakers trip fast in non-GFCI scenarios too. Even though it might seem overbuilt, it’s really about covering all possible failure modes, especially since extension cords are so often misused.

But yeah, from a pure engineering standpoint, I see your point—there's probably room for weight and material optimization with more nuanced standards.
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I believe extension cords are outside the purview of NEC. You could have an extension cord attached to the wall with make shift receptacle going all the way to a window A/C but its not part of wiring. If the extension cord's plug is not plugged into the receptacle when the inspector arrives, I don't believe they have any say on it. It's art decora.

Also, what's the difference between the below vs a hypothetical 10/2+16/1 as far as instantaneous trip?
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Flicker Index said:
You could have an extension cord attached to the wall with make shift receptacle going all the way to a window A/C but its not part of wiring.
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That situation can be pushing it to some degree as to whether the cord is being used for permanent wiring of the structure. Window AC can possibly be considered temporary, but even then don't be concealing the cord inside walls, ceiling, etc. or you are still pushing it as being permanent wiring of the structure.
 
kwired said:
That situation can be pushing it to some degree as to whether the cord is being used for permanent wiring of the structure. Window AC can possibly be considered temporary, but even then don't be concealing the cord inside walls, ceiling, etc. or you are still pushing it as being permanent wiring of the structure.
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It's an extension cord that is stored in the drop ceiling for maintenance use ;)
 
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