A 3300 sq ft house, not including car port and small storage building. Total electric. 2 AC/heat units. I'll probably use a 320 meter base and come off with 2 200 amp panels. I have a couple of questions because I've never done anything involving a generator. First, in your opinions, what size generator should I tell the home owner to buy? He wants one large enough to run the entire house on any given day. Second, the generator will be located in the storage building approx 50 ft from house. I'm sure I'll need to have discs for the 2 200 amp panels at the storage building. The panels will be in the house, in 2 different locations. Will I need to install 2 discs side by side AT THE HOUSE for these 2 panels, then use main lug panels.... or, can I just use 2 MB panels? This is new territory for me, any help is appreciated, thx.... Jason
Generator Question
- Thread starter jason
- Start date
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ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Generator Question
What does your demand calculation show? it sounds like a 320A meter might be overkill, but let the numbers sing their song.
Do they want it to be auto transfer?
What does your demand calculation show? it sounds like a 320A meter might be overkill, but let the numbers sing their song.
Do they want it to be auto transfer?
luke warmwater
Senior Member
Re: Generator Question
Jason, here the POCO won't allow the 320can for (2) 200amp panels. They require the 400amp can. But down at the beach, the same utility will allow the 320amp can. We still use the 400amp can. It might be bigger, but it is much easier to work in.
You shouldn't need disco's for the (2) 200amp panels at the remote building. Run conduit underground for the generator to the transfer switch.
That's going to be quite a large generator to run even the demand of the whole house, being that it's all electric and he wants to run the entire house.
I would probably try to convince the customer of what is really needed first. Mount the (2) 200amp panels, go from one to a transfer switch and from there into a 100amp panel for these loads. Pipe from the transfer switch to the generator. A 12kW generator would handle most neccesary loads.
If they still insist on the whole house, try either a Coleman setup or a Generac set-up that uses natural gas or propane. and you'll have to have a 320 or 400 amp transfer switch next to your meter can, and pipe from the transfer switch to the generator.
Before Y-2K, we did numerous transfer systems. Some large 3phase systems for the military that can run their whole buildings. They supplied their own Deisel generators.
Hope this helps. Todd
Jason, here the POCO won't allow the 320can for (2) 200amp panels. They require the 400amp can. But down at the beach, the same utility will allow the 320amp can. We still use the 400amp can. It might be bigger, but it is much easier to work in.
You shouldn't need disco's for the (2) 200amp panels at the remote building. Run conduit underground for the generator to the transfer switch.
That's going to be quite a large generator to run even the demand of the whole house, being that it's all electric and he wants to run the entire house.
I would probably try to convince the customer of what is really needed first. Mount the (2) 200amp panels, go from one to a transfer switch and from there into a 100amp panel for these loads. Pipe from the transfer switch to the generator. A 12kW generator would handle most neccesary loads.
If they still insist on the whole house, try either a Coleman setup or a Generac set-up that uses natural gas or propane. and you'll have to have a 320 or 400 amp transfer switch next to your meter can, and pipe from the transfer switch to the generator.
Before Y-2K, we did numerous transfer systems. Some large 3phase systems for the military that can run their whole buildings. They supplied their own Deisel generators.
Hope this helps. Todd
luke warmwater
Senior Member
Re: Generator Question
Jason ,one more thing.
You could come out of the meter (or transfer switch, depending on where you put the transfer switch) into house for your 200amp panels. Mount one MB loadcenter, and one Disconnect for the other(this keeps your grouping of discos). Run SER to remote located panel. I would use a MB for the remote located panel because of cost. I get MB's less than main lug panels.
Jason ,one more thing.
You could come out of the meter (or transfer switch, depending on where you put the transfer switch) into house for your 200amp panels. Mount one MB loadcenter, and one Disconnect for the other(this keeps your grouping of discos). Run SER to remote located panel. I would use a MB for the remote located panel because of cost. I get MB's less than main lug panels.
Re: Generator Question
The only accurate means for load determination is to plug it in and measure the current. Of course this can't be done.
The next best method is to compare this house with a few having identical connected load equipment.
The serving utility can give you the peak demand, on a house like this one.
The only accurate means for load determination is to plug it in and measure the current. Of course this can't be done.
The next best method is to compare this house with a few having identical connected load equipment.
The serving utility can give you the peak demand, on a house like this one.
Re: Generator Question
First only consider a natural gas or LP generator. Gasoline will not work for a permanent installation. The biggest problem is peak load factor. If the house has been built for a year or more you can obtain it from the utility. My guess it would be around 150 to 170 amps, which is going to be a 36 to 48 KVA generator, just a guess. It is going to be expensive to supply a generator to supply the whole house. You really need to consult with the owner and see if they really want that.
Use a single transfer switch and configure the generator as SDS. Good luck. Dereck.
First only consider a natural gas or LP generator. Gasoline will not work for a permanent installation. The biggest problem is peak load factor. If the house has been built for a year or more you can obtain it from the utility. My guess it would be around 150 to 170 amps, which is going to be a 36 to 48 KVA generator, just a guess. It is going to be expensive to supply a generator to supply the whole house. You really need to consult with the owner and see if they really want that.
Use a single transfer switch and configure the generator as SDS. Good luck. Dereck.
Re: Generator Question
Just got in, thx all for the replies. Yes, auto transfer is a must according to the customer. As far as the 320 can for 2 200 amp panels, I'm not sure about this particular county.. if they'll allow it or not, I'll have to find out... Either way, I'm never wire a home with a generator involved, i'm sure it cant be hard, but I'm just not familiar with code involving this. Also, I'm certain certain the customer isnt gonna settle for anything less than full house coverage by the generator.......... I shouldnt say this, hopefully he dont frequent this forum, but he has more money than he knows what to do with... At least thats the way it appears to me. Any advice, tips, code references, anything at all is appreciated. Thx alot.. Jason
Just got in, thx all for the replies. Yes, auto transfer is a must according to the customer. As far as the 320 can for 2 200 amp panels, I'm not sure about this particular county.. if they'll allow it or not, I'll have to find out... Either way, I'm never wire a home with a generator involved, i'm sure it cant be hard, but I'm just not familiar with code involving this. Also, I'm certain certain the customer isnt gonna settle for anything less than full house coverage by the generator.......... I shouldnt say this, hopefully he dont frequent this forum, but he has more money than he knows what to do with... At least thats the way it appears to me. Any advice, tips, code references, anything at all is appreciated. Thx alot.. Jason
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Generator Question
Article 702 for the Gen.
Article 250 for bonding and grounding
etc, etc, etc....
To be most conservative, find a 400A transfer switch. Terminate the Utility in a main disconnect (enclosed circuit breaker, service entry rated). Utility from the disc gozinta normal side of the xfer switch, gen gozinta the emergency side, and the load gozoutta to the panelboards (subpanels without a n-g bond).
Article 702 for the Gen.
Article 250 for bonding and grounding
etc, etc, etc....
To be most conservative, find a 400A transfer switch. Terminate the Utility in a main disconnect (enclosed circuit breaker, service entry rated). Utility from the disc gozinta normal side of the xfer switch, gen gozinta the emergency side, and the load gozoutta to the panelboards (subpanels without a n-g bond).
Re: Generator Question
Ron, love the wording
Jason, the only thing I can add to what Ron said is determine the peak demand if the customer insist on supplying the whole house. A 10 or 12 KVA generator will not cut it.
[ April 05, 2003, 07:14 PM: Message edited by: dereckbc ]
Ron, love the wording
Jason, the only thing I can add to what Ron said is determine the peak demand if the customer insist on supplying the whole house. A 10 or 12 KVA generator will not cut it.
[ April 05, 2003, 07:14 PM: Message edited by: dereckbc ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Generator Question
It looks like a generator that runs on propane will be your only option. as you said this house is totally electric. if natural gas is available then it would be the best choice but to handle even a load of 200 amps will take a generator of at least 48kva I don't think this would be the demand of this house though and if a little sacrifice of not using everything in the house at once then you could get away with allot less but there are calculations that have to be made to determined this and allot will depend on the heating and air-conditioning systems and what there load is and have time delays installed so the air-conditioning units cannot come on at the same time. as with any other high amperage appliances.
Click on this web site and they have a page on doing load calculations.
http://www.generac.com/default.asp
Or this site:
http://www.homestandbygenerators.com/
[ April 05, 2003, 09:40 PM: Message edited by: hurk27 ]
It looks like a generator that runs on propane will be your only option. as you said this house is totally electric. if natural gas is available then it would be the best choice but to handle even a load of 200 amps will take a generator of at least 48kva I don't think this would be the demand of this house though and if a little sacrifice of not using everything in the house at once then you could get away with allot less but there are calculations that have to be made to determined this and allot will depend on the heating and air-conditioning systems and what there load is and have time delays installed so the air-conditioning units cannot come on at the same time. as with any other high amperage appliances.
Click on this web site and they have a page on doing load calculations.
http://www.generac.com/default.asp
Or this site:
http://www.homestandbygenerators.com/
[ April 05, 2003, 09:40 PM: Message edited by: hurk27 ]
manchondo
New member
- Location
- California
Re: Generator Question
Difficult to be precise about the size generator your Mr. Rich will require without more details (nameplate info of appliances) but I think it would be in the 40 KW range. Bear in mind the generator will have to be able to start the AC units without browning out the home during start up. Time delay controls on large loads will minimize inrush current at time of tranfer, allowing the generator to come up to speed quickly, then picking up tha large loads in steps. Generator sales person will be among your best source for help. Other considerations will be sound attenuation and exhaust pipe routing (depending on location it may have to be run to elevation above the roof line). In regard to fuel, diesel is the primary choice here in California. After an earthquake, natural gas may not be available and diesel is less volatile (dangerous) than gasoline.
Difficult to be precise about the size generator your Mr. Rich will require without more details (nameplate info of appliances) but I think it would be in the 40 KW range. Bear in mind the generator will have to be able to start the AC units without browning out the home during start up. Time delay controls on large loads will minimize inrush current at time of tranfer, allowing the generator to come up to speed quickly, then picking up tha large loads in steps. Generator sales person will be among your best source for help. Other considerations will be sound attenuation and exhaust pipe routing (depending on location it may have to be run to elevation above the roof line). In regard to fuel, diesel is the primary choice here in California. After an earthquake, natural gas may not be available and diesel is less volatile (dangerous) than gasoline.
- Location
- Massachusetts
Re: Generator Question
40 KW Gen sets run from $7,000 to $13,000 plus extras. 200 to 400 Amp transfer switch $1500 to $3000 I hope these folks have deep pockets here are some links to prices.
Natual Gas Power
Diesel Power
Transfer Switch
40 KW Gen sets run from $7,000 to $13,000 plus extras. 200 to 400 Amp transfer switch $1500 to $3000 I hope these folks have deep pockets here are some links to prices.
Natual Gas Power
Diesel Power
Transfer Switch
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