parallel service entrance cables

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Brian1533

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Location
Iowa
Hi all, new to the forum and looking for a little input. I've got a 400 amp overhead service on the side of a building. 1- 2 1/2" grc into a CT cab with parallel 3/0 copper in the same raceway. From CT into 400 amp mlo with 2- 100amp breakers and 2- 200 amp breakers. Inspector here says can't have more than 1 "set" of conductors in a mast, underground would be OK but not overhead. Help please. Thanks in advance.
 

Canton

Senior Member
Location
Virginia
Occupation
Electrician
Hi all, new to the forum and looking for a little input. I've got a 400 amp overhead service on the side of a building. 1- 2 1/2" grc into a CT cab with parallel 3/0 copper in the same raceway. From CT into 400 amp mlo with 2- 100amp breakers and 2- 200 amp breakers. Inspector here says can't have more than 1 "set" of conductors in a mast, underground would be OK but not overhead. Help please. Thanks in advance.

What code article violation did he site?
 

arcsnsparks98

Senior Member
Location
Jackson, TN USA
Each conductor in the mast is supposed to exit the weatherhead through an individually opening. Might be a problem there and that certainly wouldnt be an issue underground.
 

fmtjfw

Senior Member
Each conductor in the mast is supposed to exit the weatherhead through an individually opening. Might be a problem there and that certainly wouldnt be an issue underground.

230.54 Overhead Service Locations.
(E) Separately Bushed Openings.

Service heads shall have conductors of different potential brought out through separately bushed openings.

Exception: For jacketed multiconductor service-entrance cable without splice.

This implies that multiple conductors of the same voltage (and phase angle) can be brought out through a single opening. This further implies that several conductor can have 0 potential between them, that you can have parallel conductors.
 
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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Each conductor in the mast is supposed to exit the weatherhead through an individually opening. Might be a problem there and that certainly wouldnt be an issue underground.
So what about splitting the riser with a Y or T and using two weatherhead fittings to give you a high enough hole count?
Each one would have a complete parallel set. Or two risers in parallel?
 

arcsnsparks98

Senior Member
Location
Jackson, TN USA
I think what fmtjfw has highlighted indicates that two conductors can come through the same opening if they are the same phase. Hmmm...there went my idea about the inspectors issue.
 

fmtjfw

Senior Member
Hi all, new to the forum and looking for a little input. I've got a 400 amp overhead service on the side of a building. 1- 2 1/2" grc into a CT cab with parallel 3/0 copper in the same raceway. From CT into 400 amp mlo with 2- 100amp breakers and 2- 200 amp breakers. Inspector here says can't have more than 1 "set" of conductors in a mast, underground would be OK but not overhead. Help please. Thanks in advance.

also see 230.40 Exception #3:

Exception No. 3: A single-family dwelling unit and its accessory structures shall be permitted to have one set of service-entrance conductors run to each from a single service drop, set of overhead service conductors, set of underground service conductors, or service lateral.
 

Brian1533

Member
Location
Iowa
Just an update. After looking this up for myself last night to get my argument in order so as to not look like a boob. I was pretty sure it was just a misinterpretation on the inspectors part. And first thing this morning he called me to make sure I hadn't changed anything yet, because I was right and he passed it!! Gotta say that's a first for me!! Thanks for the input tho fellas. Much apreciated.
 
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