Hey I a have question about have to ground a service panel in a duplex house at a same spot meter. One the meter main combo panel is existing with to 200 amp and the another one is 100 amp and owner wants me to upgrade the 100 amp panel to 200 amp panel. Can I use the same grounding electric conductor for both of them based on 250.58 and ground the grounded conductor in each service panel.
Grounding electrode conductors for dual services at a same building or property.
- Thread starter J.Daniel
- Start date
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Yes, you can use the same electrode for both however, it may be easier to just run a new grounding electrode conductor to the ground rods.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
You can use the same electrodes. The size of the grounding electrode conductor is typically based on the wire size (250.66). There are some cases in 250.66 where the size of the grounding electrode conductor is not based on wire size and is instead based on the electrode being used.
I thought he was asking if the grounding electrode conductor size changes because the service is being changed.
I took the quoting of 250.58 to mean he was trying to reuse the existing GEC and was mistaking the electrode section as a GEC sizing section. I might be must understanding.
I thought he was asking if the grounding electrode conductor size changes because the service is being changed.
I took the quoting of 250.58 to mean he was trying to reuse the existing GEC and was mistaking the electrode section as a GEC sizing section. I might be must understanding.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
haha - I thought he was asking if he can use the grounding electrode conductor that was existing on the 200 amp service.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
To elaborate,
When you get rid of the 100A service, your GEC size should match the other service (based on the service conductor size). .
Here is the image from the NEC handbook. You can see that the size of the electrode conductor to the electrode is based on the service entrance conductor, but the taps in the wire way have them GEC sized reduced to their respective conductor sizing.
I hope that helps.
When you get rid of the 100A service, your GEC size should match the other service (based on the service conductor size). .
Here is the image from the NEC handbook. You can see that the size of the electrode conductor to the electrode is based on the service entrance conductor, but the taps in the wire way have them GEC sized reduced to their respective conductor sizing.
I hope that helps.
That picture is really helpful and clear.