Sub-panel fed with 3 wire SE cable

D

Deke1069

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Location
SC
Occupation
Electric Contractor
The area that I work in has numerous houses with sub-panels that are fed with a 3 wire SE cable, two hots and a bare neutral/ground and all the grounds and neutrals are on the same bus bar. The obvious fix is to re-pull a 4 wire SER cable and separate the grounds and neutrals but this is a hard sell. Is it code compliant to just pull an appropriate sized separate ground from the same source as the original SE cable? Or should I pull a separate insulated neutral and use the bare uninsulated conductor in the SE cable as the ground? Also when was the first year that neutrals and grounds needed to be separated added to the code book? Must have been 50's or earlier?
 
Why does it need to be fixed at all? Even if it is "wrong" unless some serious remodeling is done, who is going to know or care. And if serious remodeling is being done you should be able to just run some new romex.

I am not sure but I don't think the code ever allowed the bare wire of SE cable to be used as a neutral for a feeder, but I don't use SE cable so maybe I am wrong on this point.

But I also do not see it as your responsibility to replace the SE cable if all you are doing is adding or replacing some circuits downstream.
 
Deke1069 said:
The area that I work in has numerous houses with sub-panels that are fed with a 3 wire SE cable, two hots and a bare neutral/ground and all the grounds and neutrals are on the same bus bar. The obvious fix is to re-pull a 4 wire SER cable and separate the grounds and neutrals but this is a hard sell. Is it code compliant to just pull an appropriate sized separate ground from the same source as the original SE cable? Or should I pull a separate insulated neutral and use the bare uninsulated conductor in the SE cable as the ground? Also when was the first year that neutrals and grounds needed to be separated added to the code book? Must have been 50's or earlier?
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The bold is your only fix. The other ideas that you've mentioned are not code complaint.
 
Deke1069 said:
The area that I work in has numerous houses with sub-panels that are fed with a 3 wire SE cable, two hots and a bare neutral/ground and all the grounds and neutrals are on the same bus bar. The obvious fix is to re-pull a 4 wire SER cable and separate the grounds and neutrals but this is a hard sell. Is it code compliant to just pull an appropriate sized separate ground from the same source as the original SE cable? Or should I pull a separate insulated neutral and use the bare uninsulated conductor in the SE cable as the ground? Also when was the first year that neutrals and grounds needed to be separated added to the code book? Must have been 50's or earlier?
Click to expand...
It is my opinion that 300.3(B)(3) acts as an exception to the charging statement in 300.3(B) and permits this, but it is unlikely you would get the AHJ to agree.
 
petersonra said:
Why does it need to be fixed at all? Even if it is "wrong" unless some serious remodeling is done, who is going to know or care. And if serious remodeling is being done you should be able to just run some new romex.

I am not sure but I don't think the code ever allowed the bare wire of SE cable to be used as a neutral for a feeder, but I don't use SE cable so maybe I am wrong on this point.

But I also do not see it as your responsibility to replace the SE cable if all you are doing is adding or replacing some circuits downstream.
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Thank you for your quick response. This was actually caught on an inspection report done for the sale of the house. I'm not sure the sale is dependent on this getting repaired or not, I was just looking for options just in case.
 
don_resqcapt19 said:
It is my opinion that 300.3(B)(3) acts as an exception to the charging statement in 300.3(B) and permits this, but it is unlikely you would get the AHJ to agree.
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The only reason I thought running a separate ground wire might be acceptable is because I believe it is acceptable to run a separate ground wire from a 120 volt device to device if the original wiring does not have a ground in it. (All residential)
 
Deke1069 said:
The only reason I thought running a separate ground wire might be acceptable is because I believe it is acceptable to run a separate ground wire from a 120 volt device to device if the original wiring does not have a ground in it. (All residential)
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It is correct that you can do that when replacing a non-grounding type receptacle or extending a branch circuit, but that section (250.130(C)) doesn't explicitly extend to subpanels or other circuits.
 
jaggedben said:
It is correct that you can do that when replacing a non-grounding type receptacle or extending a branch circuit, but that section (250.130(C)) doesn't explicitly extend to subpanels or other circuits.
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Thank you, I guess I figured that was the case.
 
petersonra said:
I am not sure but I don't think the code ever allowed the bare wire of SE cable to be used as a neutral for a feeder, but I don't use SE cable so maybe I am wrong on this point.
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IMG-20241104-075146.jpg


1940s install at grandmas house. Bare copper, two hots, and 240v service. ;)

Probably before NEC, but its working! Back in the 70s there was a QO panel upgrade. Looks weird with no sheathed neutral. Oh well.
 
chorty55 said:
IMG-20241104-075146.jpg


1940s install at grandmas house. Bare copper, two hots, and 240v service. ;)

Probably before NEC, but its working! Back in the 70s there was a QO panel upgrade. Looks weird with no sheathed neutral. Oh well.
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If this is showing a service the neutral with the ungrounded service conductors is permitted to be bare.
 
This is the entrance service panel.

The bare conductor you see in the photo is the neutral from the meter/POCO

Its just weird the panel was updated, and no one pulled a sheathed neutral.
 
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