Main Panel and Sub Panel questions and the NEC

[Guy Noir]

Hi all. I need help understanding some parts of the NEC as they pertain to my sevice feed and sub panels.

I had my service loop replaced recently from an old 60 amp service that fed 2 55 amp sub panels directly from a fused disconnect at the meter.

The new service loop is 200 amps. The existing feed lines, etc to the subpanels were kept in place and fed via 55 amp breakers, removing the old fused disconnect.

The electrician installed a 200 amp breaker panel with main lugs only (No main breaker). He said something about "As long as there are not any 100 amp feeds to subpanels, a main breaker is not required".

The electrical inspector passed the install with no problems.

Is this correct?

Also, on my subpanels, there is no "Main" breaker either. They are old screw-buss fuse panels with lugs only. If I replace them, are they REQUIRED to have a Main Breaker on the sub-panel?

I have a copy of the NEC, but I'm a little lost on these details.

THANKS!

-A

[Joe]

The final arbiter is your building inspector. If he passed it, there's no code violation. For possible changes, let the building code people answer the question. From a common sense standpoint if you get rid of fuses you need some replacement circuit protection which is in the NEC, just not obvious. Better answers can be found in wiring methods books that make the NEC legalese less obscure. Good luck.

Joe

[Guy Noir]

Sure, the fuse disconnect from the meter was replaced by circuit breakers, but the sub panels themselves have no main, lugs only. So the circuit goes from the main panel breaker to the sub lug only. Just curious if the replacements subs need mains or main lugs are fine as a replacement....

Thanks for the feedback.

-A

just not obvious. Better answers can be found in wiring methods

[Wayne Whitney]

Main lugs are fine at the subpanel as long as the feeder is protected at its source by a circuit breaker sized to its wire size. Perhaps you could provide a small diagram of the service conductors, the meter, the disconnect, the breakers, and the feeders?

Cheers, Wayne

[Guy Noir]

Sure enough Wayne.

-----Line from pole-----meter------Main Panel Lugs only------55 Amp Breaker in Main Panel---------Sub Panel 1 Lugs only | |

--------55 Amp Breaker in Main Panel---------Sub Panel 2 Lugs only

Another question, I guess, is what is the max sub panel feed I can have and not need a Main Breaker installed in the main panel. Or, is there a cummulative load that would require the addition of a Main Breaker; like if I add a 3rd panel on a 3rd 55amp breaker.

TIA!

-A

[Guy Noir]

Further reading indicates that if the Main Panel exceeeds 6 circuits/ Breakers, a main disconnect will be needed. Does a 220 (2 spaces) count as 1 circuit/breaker?

[RBM]

Sure enough Wayne.

-----Line from pole-----meter------Main Panel Lugs only------55 Amp Breaker in Main Panel---------Sub Panel 1 Lugs only

| |

--------55 Amp Breaker in Main Panel---------Sub Panel 2 Lugs only

Another question, I guess, is what is the max sub panel feed I can have and not need a Main Breaker installed in the main panel. Or, is there a cummulative load that would require the addition of a Main Breaker; like if I add a 3rd panel on a 3rd 55amp breaker.

TIA!

-A

If there is not a 200 amp disconnect at the meter equipment, you are limited to six disconnects in or at the main panel. The sub panels do not need disconnects in them unless they are in separate buildings, garages, out buildings, etc, but if the main panel is larger than what will hold 6- double pole breakers, you need a main disconnect to use those spaces

[RBM]

Further reading indicates that if the Main Panel exceeeds 6 circuits/ Breakers, a main disconnect will be needed. Does a 220 (2 spaces) count as 1 circuit/breaker?

One handle, regardless if single or double, is one disconnect

[Guy Noir]

Thanks for the info. That was very helpful! I hooked my Central Air/ Electric furnace direct to the 200A panel as well as my feeders to the subs. I'll make sure to keep it at or under 6!

[gfretwell]

Your 200a panel is not a lighting and appliance panel since the branch circuits do not originate there. You are limited to 6 disconnects in there. It could be for feeders to your fuse panels or you could add a couple big loads directly to the panel. Just remember total needs to be six or less. As long as your sub-panels are individually protected at the feed end they don't need a "main" in the panel.

[S. Barker]

So, using this line of thinking, the building inspector(s) are gods and can never make a mistake?

s

The final arbiter is your building inspector. If he passed it, there's no code violation.

Joe

[Joe]

You totally missed the point, which is: You can't fight City Hall. And also, in many years of dealing with building inspection I have had valuable help from many very knowledgeable folks. That's the way it is in small midwest towns, so YMMV. Of course we all make mistakes, including inspection staff, but IMO there's more grief from badly written codes than personnel supervising compliance. Cheers,

Joe