Min size wire from meter

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bth0mas20

Senior Member
Location
Maryland
I need to install a meter from the power company and feed only a well pump.
Is their a min code for the size of wire that I can feed from the power meter to the main breaker panel that will be inside the shed 7ft away from the shed?
 

mdshunk

Senior Member
Location
Right here.
Yes, and that wire size is dictated in large part by the chart that shows the acceptable gauges for the terminals on the load side of the meter can.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I had not thought of what Marc has mention but also take a look at 230.79.
NEC 2008 said:
230.79 Rating of Service Disconnecting Means.
The service disconnecting means shall have a rating not less than the calculated load to be carried, determined in accordance with Part III, IV, or V of Article 220, as applicable. In no case shall the rating be lower than specified in 230.79(A), (B), (C), or (D).
(A) One-Circuit Installations. For installations to supply only limited loads of a single branch circuit, the service disconnecting means shall have a rating of not less than 15 amperes.
(B) Two-Circuit Installations. For installations consisting of not more than two 2-wire branch circuits, the service disconnecting means shall have a rating of not less than 30 amperes.
(C) One-Family Dwellings. For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire.
(D) All Others. For all other installations, the service disconnecting means shall have a rating of not less than 60 amperes.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
mdshunk said:
Yes, and that wire size is dictated in large part by the chart that shows the acceptable gauges for the terminals on the load side of the meter can.

That's certainly the situation in this area. We have a lot of Cable TV service boxs with a SP 15 OCP and a #4 (socket minimum) service wire.
 

ElectricianJeff

Senior Member
augie47 said:
That's certainly the situation in this area. We have a lot of Cable TV service boxs with a SP 15 OCP and a #4 (socket minimum) service wire.

I recently replaced the service to the lighted entrance to a older subdivision here in town. The existing 2 circut load was connected with #12 thwn from the meter. The service entrance conductors where #12 also underground from the pole located about 10' away and 15' up.

I calculated the total load at less than 12 amps and upped the wire to #10 and protected it at 20 amps. No inspection was required and the POCO reconnected it with no questions.

Where would I find the "socket minimum" of a metercan? It didn't "feel" right at the time putting the #10 under the lugs of that 100 amp. can.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
ElectricianJeff said:
I recently replaced the service to the lighted entrance to a older subdivision here in town. The existing 2 circut load was connected with #12 thwn from the meter. The service entrance conductors where #12 also underground from the pole located about 10' away and 15' up.

I calculated the total load at less than 12 amps and upped the wire to #10 and protected it at 20 amps. No inspection was required and the POCO reconnected it with no questions.

Where would I find the "socket minimum" of a metercan? It didn't "feel" right at the time putting the #10 under the lugs of that 100 amp. can.

I have normally found the wire sizes listed on a sticker in the meter socket.
If not, you should be able to find them from the mfg..
For example:
http://www.milbankmfg.com/Products/Catalogs/CatalogFiles/PDF/REC.pdf
 

ElectricianJeff

Senior Member
Thanks for the link, Gus

The can was old but still served the purpose. The sticker was long since readable.

I used the logic that if the POCO ran #12 on the line side than they would love my #10 on load side.:smile: But it just didn't feel right at the time.
 

mdshunk

Senior Member
Location
Right here.
ElectricianJeff said:
I used the logic that if the POCO ran #12 on the line side than they would love my #10 on load side.:smile: But it just didn't feel right at the time.
Yeah, I've seen that a few times on some of the older billboards I work on. They'd normally skin the conductor three times too long, then fold it over three times to make it thicker for the lug. Not right, but better than a single #12 or #10.
 

ElectricianJeff

Senior Member
mdshunk said:
Yeah, I've seen that a few times on some of the older billboards I work on. They'd normally skin the conductor three times too long, then fold it over three times to make it thicker for the lug. Not right, but better than a single #12 or #10.

I've never worked on a billboard but did the same thing. I wanted to have a little more meat under that lug.
 

Buck Parrish

Senior Member
Location
NC & IN
bth0mas20 said:
I need to install a meter from the power company and feed only a well pump.
Is their a min code for the size of wire that I can feed from the power meter to the main breaker panel that will be inside the shed 7ft away from the shed?



Also when chooseing your wire size. If you have a submergible pump. Factor in the depth of your well.
 

charlie

Senior Member
Location
Indianapolis
mdshunk said:
. . . They'd normally skin the conductor three times too long, then fold it over three times to make it thicker for the lug. Not right, but better than a single #12 or #10.
I think you are correct but what is the code section that was violated? It is just a single conductor so is this a violation of the intent of the code (I don't think 110.14(A) is violated)? Is it a violation of "workmanlike" in section 110.12? Perhaps a violation that 90.4 can handle although, in my opinion, the AHJ should never use this section. :-?
 

mdshunk

Senior Member
Location
Right here.
charlie said:
I think you are correct but what is the code section that was violated?
110.3(B). A 100 amp meter can, for instance, normally lists #6 as the smallest permissible conductor. A #12, no matter if it's folded over enough times to be as thick as a #6, is still a #12 conductor.
 

charlie

Senior Member
Location
Indianapolis
HMMMM, OK.
icon11.gif
 

nakulak

Senior Member
charlie said:
I think you are correct but what is the code section that was violated? It is just a single conductor so is this a violation of the intent of the code (I don't think 110.14(A) is violated)? Is it a violation of "workmanlike" in section 110.12? Perhaps a violation that 90.4 can handle although, in my opinion, the AHJ should never use this section. :-?


I wholeheartedly disagree. I believe that article 90 should be strictly enforced, and I look forward to the day I can receive a violation listing that article.
 
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