Multi Family GEC

[MiamiValleyelec]

3 dwelling units and a house panel. 2-2 gang meter sockets. 4/0 to each meter socket. What size GEC to the water pipe? Can I run 1- #2 AL to the water and jump between the 100 amp disconnects? Or can I run 1-#2 AL to a ground bar and take a #6 cu to each 100 amp disconnect?

 

[infinity]

You can size the GEC by the using the size of the service conductors and T250.66. Can you land the GEC in the meter enclosure?

 

[MiamiValleyelec]

250.66 says size off largest ungrounded conductor. Do I need to add the 2 4/0 se cables together? Size it off 1 4/0? Or since it’s going to individual 100 amp disconnects can I size it of the #2 se cable?

 

[infinity]

What are the size of the conductors feeding the meter stack?

 

[MiamiValleyelec]

What are the size of the conductors feeding the meter stack?

4/0 AL SE to each 2 gang meter stack

 

[david]

Sounds like you're installing four ea 100 amp service disconnects.

From what you stated the largest service equipment
/ service disconnect would be 100 amp.

You didn't state what size conductor you are supplying them with

Seems pretty straightforward, no math needed to determine the largest cable supplying the service equipment/ disconnect

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[david]

You are simply looking for the size of the largest service conductor that supplies the disconnecting means
If you look at table 250.66 the first columb is titled the size of the largest ungrounded conductor

For this purpose, parallel conductors are considered a single conductor

If you have more than one set of conductors that supplies a disconnecting means you would add the circ mil area of the ungrounded conductors in that set to determine the conductors size

I have seen lots of parallel conductors supplying disconnects.

On large services I have seen sets of parallel conductors supplies to disconnecting means

Reading the code language the metering is not addressed in the section.

The largest conductor addressed in the section is the supply to the disconnecting means

The tap addressed in the section would be from the other 2 to 6 additional disconnecting means



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[MiamiValleyelec]

Ok thank you. It’s going to be 4/0 AL to the 2- gang meter than #2 AL to each 100 amp disconnect. So I’ll size it off the #2