Pedestal MSP only has one 100 amp breaker no distribution, it's calling for a 60 amp backfeed breaker to come out the pedestal panel then going to an AC combiner box ,but I have no room, my question is can I tap in to the number 2 wires on the load side of the 100 amp breaker then hit a 60 amp fuse disconnect ,or would I be better off putting a 100 amp subpanel then put a 60amp breaker in the subpanel thank you
Pedestal panel
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jaggedben
Senior Member
- Location
- Northern California
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- Solar and Energy Storage Installer
I'm assuming your job is in California....
The load side tap is not really supported under the current California code (based on 2011 NEC). The AHJ could say you're only allowed to load the feeder to 120%, i.e. 20A backfeed. (I'm assuming this a residence. If not you might be able to downsize the 100A breaker if the load isn't too high and the customer's okay with that.)
In two months (under 2014 NEC equivalent) you could do the load side tap as long as you put in a downstream 100A overcurrent device on the feeder.
You could also install a subpanel, we do this all the time, but in your case it would have to be rated 133A or more. (Practically speaking this means a 200A panel since you won't find much between 125 and 200.) That's probably what I would do if there isn't some other big difficulty to that.
The load side tap is not really supported under the current California code (based on 2011 NEC). The AHJ could say you're only allowed to load the feeder to 120%, i.e. 20A backfeed. (I'm assuming this a residence. If not you might be able to downsize the 100A breaker if the load isn't too high and the customer's okay with that.)
In two months (under 2014 NEC equivalent) you could do the load side tap as long as you put in a downstream 100A overcurrent device on the feeder.
You could also install a subpanel, we do this all the time, but in your case it would have to be rated 133A or more. (Practically speaking this means a 200A panel since you won't find much between 125 and 200.) That's probably what I would do if there isn't some other big difficulty to that.
There is not enough information to give you a solid answer. If I assume that the MSP feeds an existing distribution sub-panel somewhere and if that sub-panel is a 100A MLO, there is no reasonable way to tap into the load side without changing the sub-panel out for one with a 100A main breaker. As jaggedben wrote under 2011 you can't tap into the feeder without complying with the 120% rule. But a lot of AHJs either don't follow this or don't know about it. Consider a supply side interconnection too.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Many MLO panels have provisions for adding a main breaker without changing out the panel. I ran into a GE panel, probably 30+years old, but with a nice intact label stating the product numbers for the main breaker kits that were listed for the panel. I put the appropriate product number into eBay and found a new-old stock kit, in the original box with instructions, for less than $100. I was proud of that one.
Many MLO panels have provisions for adding a main breaker without changing out the panel. I ran into a GE panel, probably 30+years old, but with a nice intact label stating the product numbers for the main breaker kits that were listed for the panel. I put the appropriate product number into eBay and found a new-old stock kit, in the original box with instructions, for less than $100. I was proud of that one.
Good job! :thumbsup:
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