Job Design Question

[360Youth]

We went to a job to day where the customer has an existing generator and 200 amp ATS on his home with a 400 amp service, with the ATS and genset taking on one of the two panels. He wanted to know if it could be set up that both house panels would be served by the generator and ATS. First answer was a 400 amp ATS, but equipment alone was $2500+. Next answer was to redesign what he had to be fed by the single switch, which is what we ended up doing. The first necessary item was a disconnect that was never installed ahead of the ATS by the original EC. Having that 200 amp disconnecting means enabled me to feed both panels from the ATS. I am always curious and encourage comments from people that like or don't like a particular design and anxious to hear how it could be different or better. This one was a first for me and came out ok considering some of it design on the fly because all we had was customer photos to go by. Go easy on me (), but tell me what you think. Inspection will probably be next week because inspectors are taking CE courses most of this week.

BTW, the amp readings show the entire house load after everything was turned back on. I guess the original 400 amp service was a little overkill. :grin:

Service Change

 

[360Youth]

Let me add this regarding the the amp readings--this does not include stove, dryer, etc., but still a long ways off from even a 200 amp application.

 

[chris kennedy]

What is the kw of the genny?

 

[wireguru]

out of curiosity, are you under 2008, and would making this change invoke that requirement that the generator be sized to the connected load?

 

[charlietuna]

Does the customer know what his limits are? Ususally is fuel ? What is the fuel source for the generator ?

 

[cadpoint]

BTW, the amp readings show the entire house load after everything was turned back on. I guess the original 400 amp service was a little overkill.

Let me add this regarding the the amp readings--this does not include stove, dryer, etc., but still a long ways off from even a 200 amp application.

You not even following 220.80, 220.83, whats the napkin sketch look like.

Seems an "L" could have been more creative than an elbow on the outside (new old) disonnect.

What up, no home work ?'s ...

:roll:

 

[360Youth]

Seems an "L" could have been more creative than an elbow on the outside (new old) disonnect.

I hate an LB install. I use it quite often, but I prefer the sweep.

 

[360Youth]

I knew the generator questions would come...:roll:. Stay on topic, people :grin:. We are going to have to make modifications that won't allow so much load to the generator. (It is a 15kw and can be used manually until the rest of the work is done.) The HO is even considering a larger generator. I don't know that the '08 sizing rules apply because it is an existing system. But, either way, whether we lock out or load shed appliances, or go with a new generator, the panel configuration was the first step.

 

[dmagyar]

Transfer panels

Transfer panels

Thom did you take a look at any of the available transfer panels? These are the ones usually sold along with the emergency generators. They allow you to choose which loads transfer on event. Most of these have space for up to 20 circuits, which alone would exceed the capacity of the 15KW gen.

 

[ceb58]

I think now that you have rearranged things the existing system argument is out the window. However rereading your OP you stated you installed a 200amp. disco. In theory you have now taken a 400amp service (320) and now made it a 200amp service. I think you will get bitten by 702.5 2 A&B unless the load shedding is done before inspection. The inspector is not going to just go with an amp reading he will want a load cal. done.
As far as the install as it is now, some times you gotta do what you gotta do. You ask for suggestions so here is one. You could have cut out the Sheetrock under the first panel and installed a 24'' trough on the studs. Then you could have come into the end of the trough from the ATS, then out of the back into the bottom of the panel. Then replace the rock around the trough. You may have a problem with support for the flex, hard to tell by the photos.

One question where is the disconnect for the generator?

 

[360Youth]

I think now that you have rearranged things the existing system argument is out the window. However rereading your OP you stated you installed a 200amp. disco. In theory you have now taken a 400amp service (320) and now made it a 200amp service. I think you will get bitten by 702.5 2 A&B unless the load shedding is done before inspection. The inspector is not going to just go with an amp reading he will want a load cal. done.
As far as the install as it is now, some times you gotta do what you gotta do. You ask for suggestions so here is one. You could have cut out the Sheetrock under the first panel and installed a 24'' trough on the studs. Then you could have come into the end of the trough from the ATS, then out of the back into the bottom of the panel. Then replace the rock around the trough. You may have a problem with support for the flex, hard to tell by the photos.

One question where is the disconnect for the generator?

Good idea on the trough. I do so little trough work that it rarely crosses my mind, especially residential. I usually put a lv rework in the sheetrock and plate so it is a cleaner look than the "hole busted in sheetrock" that I ended up with, but the HO was ok with me using the original piece, and when I unscrewed it from the wall and flipped it, the opening lined up perfect with my flex. The generator does not have a disconnect other than its OCP about 8' from the service. I have seen the pro/con comments about its acceptability, but have never had an inspection issue with it. We are certainly going to have to address the loading issues, and it is in the works. I want to take an amp reading on a different day when the house is not just coming back online after being down for about 4 hours. There will be a more accurate reading of normal operation. That, and balancing the 120 loads would help.