service calculations

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T. M

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do you guys do a service calculation for every home you wire? Is there a quick way to do one? I usually always put in 200A on new construction but what about remodle or big additions? I also see people putting in electric plenum heaters or infloor tubing for future electric boiler these things are 15-20kw each and insome cases there is both. I would install 2 200A services for new home and use one for just the electric heat. but again in some cases H.O. will want this added to there existing service. I tell them that there service would have to be at least 200A for me to install a 15kw heater. wondering what is your common practice.
 
T. M said:
do you guys do a service calculation for every home you wire?
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For a new home, I sorta have to for the inspectors and the permits. For service upgrades, I calculate the service size with my eyeball most of the time. In your example, I think they might well need a 320 upgrade, but only a calc would say for sure. I've done a couple of those on-demand all electric water heaters, and those suckers need 150 amp all by themselves. That's an instant 320 upgrade (or more!) there.
 
We usually just eyeball it. For larger services the calculation is done by an engineer. If someone required us to perform one I would purchase some calculation software.
 
when using the optional method service calc. how do you calculate electric boilers? and electric forced air furnace? are they calculated at 100% or 65%? I know that with 4 or more baseboard heaters you can calculate at 40%. and that A/C is at 100%. But where would these fall under? also what kind of electric heat would concidered continous?
 
Around these-here parts, we have to submit a 'load letter' to the poco with the service request, which results in us receiving a number the electrical permit application requires.

So, yes.

If I'm not mistaken, all electric heat is considered continuous. It's in the book.
 
T. M said:
do you guys do a service calculation for every home you wire? Is there a quick way to do one? I usually always put in 200A on new construction but what about remodle or big additions? I also see people putting in electric plenum heaters or infloor tubing for future electric boiler these things are 15-20kw each and insome cases there is both. I would install 2 200A services for new home and use one for just the electric heat. but again in some cases H.O. will want this added to there existing service. I tell them that there service would have to be at least 200A for me to install a 15kw heater. wondering what is your common practice.
Click to expand...

I have a fill in the blank spreadsheet I use for permitting. PM me if you want to check it out.
 
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