EGC general question

Etanuye

Member
Location
Los Angeles
Occupation
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.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
If the inspector will allow the conduit to be the EGC, around here they require a wire type EGC to be ran regardless.
 

Phillip Land

Member
Location
Rome, Ga, US
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 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)
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
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)
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.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
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.
Of course. But won't that translate to the #10 having a greater share of the total voltage drop?
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
The inspector has no authority to make rules.
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.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
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.
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.
 

AC\DC

Senior Member
Location
Florence,Oregon,Lane
Occupation
EC
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.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Wel
The current flow operates the OCPD and voltage drop does not really matter
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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