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#87841 04/22/04 03:38 PM
Joined: Feb 2003
Posts: 24
I have a 30 circuit 100 amp MB panel. Have a total of 36 cicuits installed using 7 piggyback breakers. Was kicked down on inspection for overloading the panel. Panel does not state that piggyback breakers cannot be used.
Would this fall under Article 408.15 (2002)?

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#87842 04/22/04 03:55 PM
Joined: Jan 2003
Posts: 4,391
408.15 will not kick in until you get to 42 breakers (43 with your main)

Panel does not state that piggyback breakers cannot be used.

It shouldn't it has to tell you how many are allowed if any.

Bob Badger
Construction & Maintenance Electrician
#87843 04/22/04 04:09 PM
Joined: Feb 2003
Posts: 939
may i join in this one ??

ok i did look at the NEC 96 edition. old art. 384-15

" Number of overcurrent devices on one panelboard"
Not more than 42 overcurrent devices [other than those provided for in the mains] of a lighting and appliance branch-circuit panelboard shall be installed in any one cabient or cut out box.
A lightingand appliance branch-circuit shall be provided with physical means to prevent the installation of more over current devices than that number for which the panelboard was designged, rated, and approved.

so in my option here most imporat part that should read the breaker box label for listing for the numbers and types of breakers that approved for that usage

if i am off track let me know then i can correct my mistake here.

merci, marc

p.s. i did look at my french electrical codes and they say the same thing too.

Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

#87844 04/22/04 07:38 PM
Joined: Mar 2004
Posts: 32
I would like to know the theoretical loads these circuits might have. For instance, are you running lots of 20 amp circuits, electric heaters, hot water heater, electric range.... or is everything gas, and you just have alot of lighting circuits? I have a feeling this is not about the # of breakers in the panel, but the size of all the conductors and the ampacities flowing through the said breakers. Some more specifics would be nice! Thanx! Brian!

#87845 04/22/04 07:49 PM
Joined: Jan 2003
Posts: 4,391
Sparkeee24, you can have as many breakers as you want on a feeder, all that matters is the calculated load.

I have a 126 - 20 amp breakers on a 3 phase 225 amp triple tub panel at the job I am doing now, added up that would be 2520 amps. [Linked Image] In reality it is drawing a total of 150 amps (50 per phase)

Bob Badger
Construction & Maintenance Electrician
#87846 04/23/04 12:39 AM
Joined: Apr 2002
Posts: 558
Doug, if possible please post the catalog number of the panel.


Curt Swartz
#87847 04/23/04 06:13 AM
Joined: Sep 2003
Posts: 650
I seem to recall somewhere a panel that was rated for a certain total rating of all of the breakers attached to it. I don't remember which, and I don't see why (if the calculated load and the feeder rating is less than the ampacity of the bars, who cares what the total of the CB ratings is), but if that is the listing, then that is the listing.

I have also seen panels where the instructions specifically limited the total rating of CBs connected to a single stab on the bus. This is more reasonable, since the rating of the stab might be less than that of the entire bus.


#87848 04/23/04 04:04 PM
Joined: Apr 2004
Posts: 201
You are permitted to use all the spaces in a panelboard in accordance with its listing. If you have a 20/40 panelboard, you may use all the spaces and all of the circuit breakers may be ½" breakers. [Linked Image]

Charlie Eldridge, Indianapolis Utility Power Guy
#87849 04/26/04 04:21 AM
Joined: Jun 2003
Posts: 681
This is a listing and labeling issue - 110.3(B). If the label lists this panel for a maximum of 30 ckts, that is all that is permitted. Reading the label will tell you if you are permitted to have more than 30 ckts (breakers).


Pierre Belarge

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