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tjmicsak

tjmicsak

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Installed a Main Panel on outside of house. Service Entrance goes to main 200a CB as disconnect and then has space for 2 sub breakers on the panel buss. Have 100a subfeed going to garage. Have space for one more CB, and also have lugs at bottom of the panel bus to use as a feed-thru. This I believe is called a "riser panel". The bus is shifted over to one side. The home owner wants everything he can get out of this into the house supply. I cannot get a 150a CB to use as a subfeed off the bussbar, only 125a. Is there any reason why I cannot run 200a SE from the lugs at the buss bottom into a 200a interior house main lug panel? The main 200a CB in this outdoor disconnect will protect the house feed, but I am concerned about the 100a subfeed branch on this panels buss. This 100a CB goes to a mian lug 100a garage panel 4-wire underground, all sized for the current rating of 100a. The garage load is minimal, and the house has elec. range, dryer, and possible AC in future, but I estimate that the load will be under 100a. Can I just feed the house from the protected lugs at the buss bottom?
 
If I understand you correctly, I see no problem with feeding the house from the lugs at the bottom of the panel. Your feeder to the house panel will need to be 200 amps and will need to be a 4-wire feeder. The house panel will now be a sub-panel. If the load in the house, plus the load in the garage exceeds 200 amps, then the main breaker will trip. It does not sound like you have performed a load calculation. If you do, you will probably find that the calculated load is much less than 200 amps.
 
I agree with haskindm's answer. But I do recommend that you perform a service load calculation, just to be certain.

tshea said:
What is an electrical administrator?
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I have that license in Washington State. Every electrical contracting company must have one person (who possesses this license) formally designated (i.e., by a documented action by the owner or by the board of directors) as being the company's EA. Essentially, that person is responsible for assuring code compliance and for assuring that the employees use safety working practices.
 
Service/Feeder

Service/Feeder

Well the deal is this. The old 100a sub panel in the house fed the garage on a sub-sub feeder from it. So by moving it to it's own CB at the main outdoor 200a service panel, it did not change the load, only relocated it off the inside sub panel. Now the service/disconnect outdoors was upsized from 100a to 200a. No load was added to the house, and only a future AC unit is expected to be run from the house at some later point, maybe adding 20 amps to the calc. Dryer and range were already electric. My experienced guess would be that the total load on the old panel was under 100A because there were no issues with overcurrent. So if upsizing for future capacity, wouldn't a load calc simply confirm what we already know?
 
Re: Service/Feeder

Re: Service/Feeder

tjmicsak said:
. . . wouldn't a load calc simply confirm what we already know?
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How can anyone answer that, without first seeing the results of the load calculation? But if indeed no load is being added at this time, there is no need to perform such a calculation.
 
On the other hand, though, this house may have been expanded incrementally over time, without ever doing a load calc. It would be a good idea to do a load calc on the home at this time, when a professional is overseeing the work.

Having said that, find your own avatar, dude. :lol:
 
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