EGC general question

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PowerdT

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Electrical Engineer
I have 60A, 208V feeder to feed 60A 102/208V panel.

Due to the length, I upsized the conductor to 4#4AWG + 10G. I realized I didn’t upsize the EGC. Will I be ok with this?
Thank you.
 
If the inspector will allow the conduit to be the EGC, around here they require a wire type EGC to be ran regardless.
 
Etanuye said:
I have 60A, 208V feeder to feed 60A 102/208V panel.

Due to the length, I upsized the conductor to 4#4AWG + 10G. I realized I didn’t upsize the EGC. Will I be ok with this?
Thank you.
Click to expand...
If you use a wire type egc I think you need to upsize to #8 because when increasing from 6awg (26,240 cm) to 4awg (41,740 cm) that's an increase of 1.59
10awg has a cm of 10,380 which when multiplied by 1.59 = 16,504.2 cm
8awg is 16,510 cm
I would install an 8awg egc

some might say that you don't have to go with 8awg until 100 amps per Table 250.122 but I'm just looking at the rule ad it's written and erring on the side of caution that is in keeping with 250.4(A)(5)
 
Phillip Land said:
If you use a wire type egc I think you need to upsize to #8 because when increasing from 6awg (26,240 cm) to 4awg (41,740 cm) that's an increase of 1.59
10awg has a cm of 10,380 which when multiplied by 1.59 = 16,504.2 cm
8awg is 16,510 cm
I would install an 8awg egc

some might say that you don't have to go with 8awg until 100 amps per Table 250.122 but I'm just looking at the rule ad it's written and erring on the side of caution that is in keeping with 250.4(A)(5)
Click to expand...
I agree that is what the code requires, but when you run the numbers you will find that the 4AWG with the 10 AWG EGC will flow slightly more fault current than the 6 AWG with the 10 AWG EGC. This assumes the same circuit length in both cases.
 
don_resqcapt19 said:
I agree that is what the code requires, but when you run the numbers you will find that the 4AWG with the 10 AWG EGC will flow slightly more fault current than the 6 AWG with the 10 AWG EGC. This assumes the same circuit length in both cases.
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Of course. But won't that translate to the #10 having a greater share of the total voltage drop?
 
petersonra said:
The inspector has no authority to make rules.
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Right, but they do have the authority to make life hell or like roses.
And quite frankly I know many on here have there views about how they like to handle the EGC whether it be the wire method or conduit. I myself prefer running a redundant EGC because I have seen what happens when one of those conduit connections becomes loose or compromised.
 
don_resqcapt19 said:
I agree that is what the code requires, but when you run the numbers you will find that the 4AWG with the 10 AWG EGC will flow slightly more fault current than the 6 AWG with the 10 AWG EGC. This assumes the same circuit length in both cases.
Click to expand...
In other words, the code section makes very little sense. The assumption is that wires will only be upsized for voltage drop over very long wire runs. And yet if the wire is very long but not sized to account for voltage drop, the code section doesn't kick in, even though the danger it putatively addresses is greater.
 
Don't know quit how you're set up is, but can you just install the proper overcurrent for that wire size and type. would avoid re-pulling the wire. Won't work if you have to keep overcurrent at 60 amps.
 
Wel
don_resqcapt19 said:
The current flow operates the OCPD and voltage drop does not really matter
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Well yes and no, the voltage drop would reduce the fault current, increasing the time for the ocp to trip. I’ve had that happen on long parking lot runs. Does it matter? Depends on the situation. Tends to destroy the breakers quicker because the fault current on the contacts though lower, is not cleared as fast.
 
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