40KW on 200A Single Phase Service

[Gogreen100]

In an existing house with 1 200A service, is going to have a new dual fuel heating system put in. 1 gas forced air furnace as back-up. 1 20KW plenum heater and 1 20KW boiler (floor heat) as primary.
The job has been put together by a local firm and electrical specs sent out for contractors to bid on.
1-Install 2nd 200A electrical service. 230.2(D)
2-Wire 40KW of new electric heat to new service.
3-Etc.
Question:

Is 40KW to much for a 200A 120/240 1ph service?
Can you derate any of the heat?
Do you have to add 125% on to the calcutated load?
220.51 states it shall be calculated at 100%.

I live in border city and have asked both local inspectors and have got 2 different answers.

 

[bphgravity]

To start with, I wouldn't approve the second service using 230.2(D) or any other part of 230.2

You simply need to increase the rating of the existing service to accomodate the new loads using Section 220.83(B) of the NEC.

 

[charlie b]

If the existing service is 120/240 volt (you didn't say what it was), then I agree with Bryan: You are not allowed to install another 120/240 volt service for the new loads. I would suggest submitting an RFI (or other appropriate document) to communicate a concern to the engineer who issued the plans. The engineer has made a design error, and you cannot properly bid the installation until this issue is resolved.

To answer your three questions and your one statement, in order:
No.
No.
No.
I agree.

 

[peter d]

Is 40KW to much for a 200A 120/240 1ph service?

The poco absolutely needs to be notified about this situation.

Also, I hope you live in an area where electricity is cheap, or their electric bill will look something like the national debt.

 

[Gogreen100]

To start with, I wouldn't approve the second service using 230.2(D) or any other part of 230.2

You simply need to increase the rating of the existing service to accomodate the new loads using Section 220.83(B) of the NEC.

230.2(D) would approve a second service becauce it is for dual fuel rates (different rate schedules) that the electric utility provides. Most of the utilities around here don't do ct metering or subtractive metering. So to get the dual fuel rate a second meter and panel is required.

 

[bob]

The job has been put together by a local firm and electrical specs sent out for contractors to bid on.
1-Install 2nd 200A electrical service. 230.2(D)
2-Wire 40KW of new electric heat to new service.
3-Etc.

Go
Are you asking for the utility to install a second service to the house at a different location or asking to install a second 200 amp panel at the existing service point?

 

[Gogreen100]

Go
Are you asking for the utility to install a second service to the house at a different location or asking to install a second 200 amp panel at the existing service point?

Bob
A 2nd 200 amp panel at the existing service point. A twin 200A meter socket refeeding existing 200A panel and new 200A dual fuel (different rate schedule) heating panel. Electric utillity shall provide and be resposible for service lateral.

 

[bob]

Bob
A 2nd 200 amp panel at the existing service point. A twin 200A meter socket refeeding existing 200A panel and new 200A dual fuel (different rate schedule) heating panel. Electric utillity shall provide and be resposible for service lateral.

If so, then I see no reason why you could not do what you are proposing since there is only one service.
Maybe Charlie and Bryan may have misunderstood you proposal. I will say that with 40kw on the 200 amp panel you will be able to fry your eggs for breakfast.

 

[LawnGuyLandSparky]

Aside from the code issues, why would anyone install a heat system where electric is the primary and gas is the secondary? Shouldn't it be the other way around?

 

[LarryFine]

Aside from the code issues, why would anyone install a heat system where electric is the primary and gas is the secondary? Shouldn't it be the other way around?

Maybe it depends on which costs more per BTU.

 

[charlie b]

If the utility really does give different rates for this particular type of load, then I withdraw my earlier statement that it is not allowed. I would agree that 230.2(D) does allow this. I standby the rest of the responses I gave in Post #3.

 

[bob]

If the utility really does give different rates for this particular type of load, then I withdraw my earlier statement that it is not allowed. I would agree that 230.2(D) does allow this. I standby the rest of the responses I gave in Post #3.

Assume that the rates are not part of this installation. The OP said there is only one service. Why do you feel that the installation is a violation?

 

[charlie b]

Assume that the rates are not part of this installation. The OP said there is only one service. Why do you feel that the installation is a violation?

Because the OP also said that the intent was to install a second service. Only one service is allowed to any building, unless you meet one of the conditions described in sub-paragraphs (A) through (D). This installation would not meet any of those conditions, if it were not for the separate utility billing structure.

 

[augie47]

Would a 200 amp service not be slighly undersized base on 424.3 ?

 

[bob]

Because the OP also said that the intent was to install a second service. Only one service is allowed to any building, unless you meet one of the conditions described in sub-paragraphs (A) through (D). This installation would not meet any of those conditions, if it were not for the separate utility billing structure.

If you read my first post, I asked if there were 2 utility services. The OP responded and said there was going to be one underground service lateral feeding 2 200 amp panels. If there were 2 services I would agree with your statement.

 

[76nemo]

Because the OP also said that the intent was to install a second service. Only one service is allowed to any building, unless you meet one of the conditions described in sub-paragraphs (A) through (D). This installation would not meet any of those conditions, if it were not for the separate utility billing structure.

Charles, can you point me to that dictation, one service to any building? I have seen that broken many o' times then:-?

 

[charlie b]

Charles, can you point me to that dictation, one service to any building? I have seen that broken many o' times then:-?

230.2 (2005 Edition). There are four sub-articles, (A) through (D), that give circumstances in which a single building is allowed more than one service. You may have seen examples of these allowable circumstances.

By the way, call me "Charlie." :smile:

 

[76nemo]

230.2 (2005 Edition). There are four sub-articles, (A) through (D), that give circumstances in which a single building is allowed more than one service. You may have seen examples of these allowable circumstances.

By the way, call me "Charlie." :smile:

Darn, that was QUICK!!! And, "Sorry", my best friend's name is Charles, that was out of habit Charlie. Thank you for the lightning fast response. That's great!

 

[Gogreen100]

Would a 200 amp service not be slighly undersized base on 424.3 ?

Is'nt 424.3 about branch circuits only, not service calculations?

 

[bpk]

If the heat is expected to run for more than 3 hours continuously wouldnt it be considered a continuous load and be sized 125%. Article 230.42 relates to the service entrance conductors being sized 125% but I dont know if a service panelboard needs to be sized 125% or not ?