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#58769 - 11/19/05 12:10 AM No Main Disconnect on Panel?  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
Saw a residential breaker panel today that was an old Murrey split buss panel. It did not have a main disconnect. It was fed underground to the meter and directly from the meter with 3/0 wire and thats it. Are these fused at the transformer?


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#58770 - 11/19/05 12:30 AM Re: No Main Disconnect on Panel?  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,223
SI,New Zealand
Al,
That sounds like a nightmare!. [Linked Image]
How can you have a panel without any disconnect switch in it?


#58771 - 11/19/05 12:38 AM Re: No Main Disconnect on Panel?  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
I don't know, but there definetly was not a main disconnect. I can't ever remember seeing this. I'll check to see if the whole neighborhood was this way. I'm guessing it was.


The Golden Rule - "The man with the gold makes the rule"

#58772 - 11/19/05 12:51 AM Re: No Main Disconnect on Panel?  
stamcon  Offline
Member
Joined: Mar 2001
Posts: 329
So San Francisco CA
If it was a split bus panel, were there 6 breaker positions on the line side of the buses?

steve


#58773 - 11/19/05 05:46 AM Re: No Main Disconnect on Panel?  
huungrycat  Offline
Junior Member
Joined: Apr 2002
Posts: 7
myrtle beach,s.c.usa
YOU INSTALL A BREAKER IN THE TOP SECTION TO FEED THE LOWER SECTION THIS KEEPS YOU WITHEN THE 6 RULE


#58774 - 11/19/05 08:10 AM Re: No Main Disconnect on Panel?  
winnie  Offline
Member
Joined: Sep 2003
Posts: 649
boston, ma
230.71 permits a set of up to six breakers or switches to be used as the 'service disconnecting means'. The split buss panels would have 6 breakers feeding things like the electric range, dryer, AC, etc. with one of these breakers feeding the rest of the panel. This 'six throws of the hand' rule is still code.

408.16 would seem to prohibit the split buss panels for new installations.

I guess the 'modern' use of 230.71 in residential applications would be a pair of 200A panels installed for a 400A service, without a 400A main breaker.

-Jon


#58775 - 11/19/05 09:21 AM Re: No Main Disconnect on Panel?  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
Yes it does have the 6 breakers on top all 240 volt with one 60a feeding the lower buss. So that serves as the 6 breaker disconnect rule? You still cannot shut down the whole panel at once, which seems to be code.

winnie, I installed a 400 amp panel a few years ago feeding a 100a from that. If I remember right, the 400a had 2-200a mains feeding a split buss. So that would take 2 mains to shut down the panel.
Art 408.16 does seem to say you cannot have more than 2 disconnects.


The Golden Rule - "The man with the gold makes the rule"

#58776 - 11/19/05 10:09 AM Re: No Main Disconnect on Panel?  
mahlere  Offline
Member
Joined: Nov 2005
Posts: 507
New Jersey
I believe that sec 408.16 is referring to the protection of the feeders to the appliance/lighting panelboard. (i.e. a 200A CB in the MDP prior to the feeder and then another 200A CB in the panelboard= 2 disconnects)

what should be in play here is Sec 230.71(A).

Think of it in terms of a 6 ckt MDP feeding subpanels.


#58777 - 11/19/05 02:22 PM Re: No Main Disconnect on Panel?  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
mahlere,
Think your right, guess they'd have to be really large appliances to exceed the main panel rating.


The Golden Rule - "The man with the gold makes the rule"

#58778 - 11/20/05 11:38 AM Re: No Main Disconnect on Panel?  
DougW  Offline
Member
Joined: Jun 2003
Posts: 1,143
North Chicago, IL
One of the guys at the FD says he doensn't have a main D/C on his resi panel either... IIRC, the house dates back to the late 50's - early 60's.

I offered to take a look (for free, since he's a co-worker) and offer some constructive advice, but he'd rather just sit around and gripe about it. [Linked Image]



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