Requirements for 2 services in a building

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Tainted

Tainted

Senior Member
Location
New York
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Engineer (PE)
Client wants to completely get rid of their old boiler and replace it with an electric one. The existing building has 208V 3 phase. To install this boiler I think it might need a electrical service rated at 480V due to the boiler being really high in btu/h (Approx 7.5M btu/h).

Can the building have more than 6 service switches if the building has 2 services with different voltages?

Do the 480V service switches have to be grouped together in the same room with the 208V services switches? If no, how far away are they allowed to be?
 
Tainted said:
Can the building have more than 6 service switches if the building has 2 services with different voltages?
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Yes. Each service can have up to 6 disconnecting means.
Tainted said:
Do the 480V service switches have to be grouped together in the same room with the 208V services switches? If no, how far away are they allowed to be?
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No, the services do not have to be in the same room. There is no distance requirement. Each service shall have a plaque denoting the location of the other service.
 
david luchini said:
Yes. Each service can have up to 6 disconnecting means.

No, the services do not have to be in the same room. There is no distance requirement. Each service shall have a plaque denoting the location of the other service.
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Simple as that? Is there anything else I have to worry about? Do the 2 different services have to be in 2 separate 2 hour fire rated rooms?
 
Tainted said:
Client wants to completely get rid of their old boiler and replace it with an electric one. The existing building has 208V 3 phase. To install this boiler I think it might need a electrical service rated at 480V due to the boiler being really high in btu/h (Approx 7.5M btu/h).

Can the building have more than 6 service switches if the building has 2 services with different voltages?

Do the 480V service switches have to be grouped together in the same room with the 208V services switches? If no, how far away are they allowed to be?
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do they realize what their energy bill will be like when this is all done? Especially if in NY or most of that region?
 
kwired said:
do they realize what their energy bill will be like when this is all done? Especially if in NY or most of that region?
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Where NYC is going, it's inevitable that at some point they will start mandating no gas in existing buildings in the future. Right now no gas will be allowed in new buildings in NYC. It's just to prepare for the future.
 
Tainted said:
Where NYC is going, it's inevitable that at some point they will start mandating no gas in existing buildings in the future. Right now no gas will be allowed in new buildings in NYC. It's just to prepare for the future.
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I wouldn't count on it. All depends on politics and what happens next.

-Hal
 
hbiss said:
I wouldn't count on it. All depends on politics and what happens next.

-Hal
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I know, this brings up another interesting question. How much kilo-watt hours do these boilers usually consume in a day during the high demand? I know they don't run continuously for a whole day. I want to compare gas price vs electric during a month period. In NYC, rule of thumb it's about $0.20/kWh but for gas I'm not sure how many therms per month and how much
 
Tainted said:
I know, this brings up another interesting question. How much kilo-watt hours do these boilers usually consume in a day during the high demand? I know they don't run continuously for a whole day. I want to compare gas price vs electric during a month period. In NYC, rule of thumb it's about $0.20/kWh but for gas I'm not sure how many therms per month and how much
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Just comparing energy cost:
A therm of nat gas is the energy-equivalent of 29.3 kwhr of electricity. For your gas and electric price to be the same, gas would have to be $5.86 per therm (0.20 x 29.3). I’d guess it’s probably less than 1/3 of that even at today’s high prices.
 
retirede said:
Just comparing energy cost:
A therm of nat gas is the energy-equivalent of 29.3 kwhr of electricity. For your gas and electric price to be the same, gas would have to be $5.86 per therm (0.20 x 29.3). I’d guess it’s probably less than 1/3 of that even at today’s high prices.
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You do have to calculate in efficiency for the gas. I think somewhere around 70% is typical.
 
Tainted said:
Where NYC is going, it's inevitable that at some point they will start mandating no gas in existing buildings in the future. Right now no gas will be allowed in new buildings in NYC. It's just to prepare for the future.
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So what is used for standby sources, optional or required standby?
 
ptonsparky said:
2700 amp 480v 3ph service for a water heater
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We'll see how well that goes. There is no alternative to nat gas other than electric and that isn't really an alternative. I want to know what new 100 story buildings are doing for heating and cooling. Geothermal? Guaranteed it isn't resistance heat.

We are also going to see how long the politicians and environmentalists can hold out...

-Hal
 
Did they ban this sort of thing? How big of one do you need for a high rise building? How big of a wood shed needs to go with it?

Ones with a gas burner as a backup source are not very efficient at all. Is about like those conversion kits they used to put on wood/coal burning furnaces/boilers years ago to allow them to run on gas/LP.

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