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#66921 - 06/22/06 09:18 PM Six Switches?  
master66  Offline
Joined: Apr 2002
Posts: 257
Masontown, PA, USA
Went to inspect a 400 amp service today for a storage building. The electrician mounted an underground meter socket feeding a panel with 500MCM. The problem... The panel was 120/240 single phase. Main Lug Only,40 circuit. No main breaker.

He said that he was only installing 3 2-pole breakers to feed the buildings and didn't need a main because it was less than 6 switches. He also said that this installation has been approved before (on a smaller scale) on bill boards.

Am I wrong not to approve this installation?

I couldn't find anything, scanning through fast, in the NEC stating how to assure that no more than 6 mains are installed in the future.

Also, I could not find a label on this panel saying "Suitable for use as service equipment".

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#66922 - 06/22/06 09:24 PM Re: Six Switches?  
e57  Offline
Joined: May 2003
Posts: 2,876
Nothing to assure no more than six, just that no more than six are installed. Not suitable as service equipment is another story. Thats 230.66...

Mark Heller
"Well - I oughta....." -Jackie Gleason

#66923 - 06/22/06 10:27 PM Re: Six Switches?  
Bob  Offline
Joined: Feb 2002
Posts: 182
Mobile, AL, USA
This question has come up before. Are you,
as an inspector, required to judge what will happen in the future or is you job to judge the existing installation. As installed, the panel meets the 6 breaker rule. He shouldn't
have installed the panel as is but what are you to do?

#66924 - 06/23/06 01:11 AM Re: Six Switches?  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,142
Vote me with e57. It has to be suitable for service equipment.

Greg Fretwell

#66925 - 06/23/06 06:09 AM Re: Six Switches?  
Dnkldorf  Offline
Joined: Dec 2004
Posts: 1,064
nowhere usa
230.71 indicates we could have more than six switches.

Does he need to tell you now, that he MAY plan on installing TVSS, or power monitoring equip?

#66926 - 06/23/06 03:56 PM Re: Six Switches?  
circuit man  Offline
Joined: Nov 2001
Posts: 273
master 66, why did he build a 400 amp service for just 6 breakers any how? couldn'the have built a 100 amp service for the storage buildings?it may not be allowed to be less than 200 amp for anything out your way.but a 400 amp sounds mighty big for a couple of storage buildings.belive he might have other plans.

#66927 - 06/23/06 04:15 PM Re: Six Switches?  
master66  Offline
Joined: Apr 2002
Posts: 257
Masontown, PA, USA
These are to be "Climate controlled" storage units.

#66928 - 06/23/06 06:49 PM Re: Six Switches?  
e57  Offline
Joined: May 2003
Posts: 2,876
Bust 'em! Make him ad a disco...

Mark Heller
"Well - I oughta....." -Jackie Gleason

#66929 - 06/23/06 07:15 PM Re: Six Switches?  
electure  Offline

Joined: Dec 2000
Posts: 4,262
Fullerton, CA USA
I'd question the 500MCM he's got it wired with. If the terminal ratings are 75 degrees, the 500's ampacity is 380 Amps.

#66930 - 06/24/06 10:34 AM Re: Six Switches?  
SolarPowered  Offline
Joined: Jul 2004
Posts: 625
Palo Alto, CA, USA
One wonders why he put in that panel instead of a 12-pole, 400A, MLO panel that's service rated.

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