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

Flicker Index

Flicker Index

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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.
 
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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You don't want to wait until you've gotten shocked to have the fault deenergized. The GFCI might save your life but the shock can still cause an injury because of shock reaction of your body. It is not a fun time had by all.

With an adequately sized Equipment Grounding Conductor (EGC) the Over Current Protective Device (OCPD) will open the moment the fault occurs and thus deenergize the fault prior to human contact. The impedance of the Fault Current Pathway is a critical factor in the speed of the OCPD's operation. If testing were to show that the operation of the OCPD was not significantly slowed by the reduced size of the EGC I don't think anyone would oppose the reduction in the EGC's size. Given the very high price of copper right know I suspect that the testing has already been done and the results were unfavorable.
 
hornetd said:
The impedance of the Fault Current Pathway is a critical factor in the speed of the OCPD's operation. If testing were to show that the operation of the OCPD was not significantly slowed by the reduced size of the EGC I don't think anyone would oppose the reduction in the EGC's size. Given the very high price of copper right know I suspect that the testing has already been done and the results were unfavorable.
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What timescales are we talking about:
both the trip curve time for reduced copper,
and the health effective time of an electrical shock.

Are we talking minutes, seconds, miliseconds, nanoseconds? One 60hz cycle, half a 60hz cycle, four 60 hz cycles?

Note also like half, or more, of the extension cords I encounter at constuction sites, often outdoors or partially so
have the ground prong yanked out of the cord. THAT copper ain't doing nobody no 'good .
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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.
Click to expand...
Setting aside the entire question of in-line GFCI, might it be that using three same-sized conductors makes it so ease of manufacturing offsets the additional copper cost?
 
brycenesbitt said:
What timescales are we talking about:
both the trip curve time for reduced copper,
and the health effective time of an electrical shock.

Are we talking minutes, seconds, miliseconds, nanoseconds? One 60hz cycle, half a 60hz cycle, four 60 hz cycles?

Note also like half, or more, of the extension cords I encounter at constuction sites, often outdoors or partially so
have the ground prong yanked out of the cord. THAT copper ain't doing nobody no 'good .
View attachment 2576885
Click to expand...
I didn't say that I had done or was aware of the results of any specific testing. I speculated that with the present cost of copper the testing has probably been done and since there is no proposal in process right now to change the size required by the laboratory testing Standard for portable cords that any testing which has been done must have produced unfavorable results which would not justify the reduction in the size of the Equipment Grounding Conductor based on the size of the energized conductor.

Your use of the unlawful removal of the EGC connection pin from extension cord plugs is a straw man argument. It has absolutely nothing to do with the sizing of the EGC. The EGC is required to prevent fault current from travelling on exposed conductive normally non current carrying parts of the electric system and other conductive materials in contact with the conductive parts of the electrical in ways that would cause a dangerous touch potential. The purpose of a GFCI is to prevent the electrocution of a person who is already in contact with a conductive surface that is energized by the simultaneous occurrence of a fault.

You are intent on justifying the reduction in size of the EGCs in extension cords. Your speculation on the safety of that change is no more valid then mine about the likelihood of testing having been done nor on the likely outcome of any such testing. Let me suggest that you ask yourself if the resultant savings on the cost of the EGC would not be offset by the cost of manufacturing cords with in line Ground Fault protection.

You might also look at the likely operational longevity of the inline GFCI device and what may well happen once it has been damaged. Can we be confident that the user would not replace it with a plug, given how much less that would cost than a replacement in line GFCI. Add into your consideration what is more likely to get damaged. Is it the OCPD that is within the protection of a panel enclosure? or the GFCI that is getting dragged around on the end of an extension cord.

It is a basic principal of law that the State may not presume the commission of a crime. Using the unlawful removal of the Equipment Grounding Conductor (EGC) connection pin from a cord set's plug to justify changing the electrical requirement of the State Government is exactly that kind of presumption.
 
hornetd said:
Your use of the unlawful removal of the EGC connection pin from extension cord plugs is a straw man argument. It has absolutely nothing to do with the sizing of the EGC.
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I care about the safety of entire systems,
so its a relevant consideration. Earplugs work only when in ears. Helmets work only on heads (unless being used to carry water). The system matters.
 
Is GFCI protecting against all fault types to protect the cord? Is there a EGC wire sizing increase on cords similar to 250.122(B)?

Would it protect the cord from an internal fault like a insulation failure?

I would think the increased impedance might have a negative impact on the cord's ability to properly clear the fault. I don't know if the GFCI component of it is enough.
 
Elect117 said:
Would it protect the cord from an internal fault like a insulation failure?
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Yes: past the GFCI lump, yes.
It won't protect the cord exactly, but rather the user.
Elect117 said:
I would think the increased impedance might have a negative impact on the cord's ability to properly clear the fault. I don't know if the GFCI component of it is enough.
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Not an issue, as the EGC will be connected straight through.
The increased impedance of the GFCI lump relay could lead to point heating if cord is used above capacity (an issue on construction sites). But the EGC itself should be a straight shot back to the panel. A non GFCI cord might just get warm in the same situation.

Cord lumps may have GFCI only, or GFCI plus OCPD.
 
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.
Click to expand...
GFCI's aside unless I missed something obvious and its already allowed I'd start with the 8 awg and 6 awg sizes, perhaps a public input (code change proposal) to 400.5 allowing flexible cords to use table 250.122 for sizing the equipment ground, like a 6-6-10 or a 8-8-10.
 
Elect117 said:
Is GFCI protecting against all fault types to protect the cord? Is there a EGC wire sizing increase on cords similar to 250.122(B)?

Would it protect the cord from an internal fault like a insulation failure?

I would think the increased impedance might have a negative impact on the cord's ability to properly clear the fault. I don't know if the GFCI component of it is enough.
Click to expand...
A GFCI only responds to current escaping from the circuit. Unless the circuit goes out of balance between the current flowing on the Grounded Conductor and the energized conductor by at least 6 milliamperes the GFCI will not be involved in what is going on because the mechanism is only designed to detect imbalance. A fault between the Grounded Conductor (EGC) and the Energized Conductor, commonly called a short circuit, would continue until the GFCI was destroyed because no matter how high that fault current was a GFCI mechanism does not respond to the number of amperes flowing. Only an Over Current Protective Device, such as a fuse, circuit breaker, or an overcurrent relay will open the circuit due to excess current flow.

It will only protect the cord from a fault between the Equipment Grounding Conductor (EGC)and the energized conductor such as might be caused by the cord being crushed. A GFCI does not respond to a fault between the Grounded Conductor and the Energized Conductor. Since a GFCI does not respond to an overcurrent condition it will not protect the cord from a Grounded Conductor to Energized Conductor.

The most likely place for a fault to occur is in the load that is supplied by the cord. As an example a flood light might have its energized supply conductor fault to its conductive shell. In the absence of a low impedance pathway to the source the shell would remain energized until a person went to find out why it wasn't working and touched the energized shell. A shock current greater than 6 milliamperes would trip the GFCI and deenergize the fault thus ending the shock. In the event of an Energized Conductor to Grounded Conductor fault occurred If the cord had an adequate EGC then the magnetic coil in the circuit breaker would trip the circuit breaker's contacts open thus deenergizing the fault prior to human contact. Preventing the shock is more valuable then opening the circuit after a shock has begun.
 
Na I think you'd have to start with the NEC, then UL would follow.
But then again why stop at GFCI protected cords? Why not harmonize 250.122 with Canada's CEC equivalent Table 16, its just one tiny change in the table most of it aligns.
 
tortuga said:
GFCI's aside unless I missed something obvious and its already allowed I'd start with the 8 awg and 6 awg sizes, perhaps a public input (code change proposal) to 400.5 allowing flexible cords to use table 250.122 for sizing the equipment ground, like a 6-6-10 or a 8-8-10.
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I don't think there is anything prohibiting a 6-6-10 cord, you just don't see it much at all. There are range cords out there with 6-6-8-8 conductors in them. Honestly feel they could be usually be 6-6-10-10 but they probably won't listen to me. I seem to recall mobile home or even RV supply cords with at least a reduced green conductor.
 
tortuga said:
Na I think you'd have to start with the NEC, then UL would follow.
But then again why stop at GFCI protected cords? Why not harmonize 250.122 with Canada's CEC equivalent Table 16, its just one tiny change in the table most of it aligns.
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It has gone both ways. Sometimes with UL going first, and sometimes with UL telling the NEC to make a rule that requires a change in the standard.
 
kwired said:
I don't think there is anything prohibiting a 6-6-10 cord, you just don't see it much at all. There are range cords out there with 6-6-8-8 conductors in them. Honestly feel they could be usually be 6-6-10-10 but they probably won't listen to me. I seem to recall mobile home or even RV supply cords with at least a reduced green conductor.
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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;

adapter.png
 
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;

View attachment 2576930
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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.

Of course overcurrent protection for the 5/20R receptacles here is another thing, 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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