Load calculation question and advice

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McLintock

McLintock

Senior Member
Location
USA
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Electrician
Have a costumer that as a all electric house, as a 20kW furnace. Wired in the house and he is right at 160 amps (200 amp service), now he is turning the garage into his “man cave” and is insisting on baseboard heat in there to have on when he is not there (it’s a 2nd home).

Told him we cannot do that as it is a fixed unit and will be used all the time. Gave him options of running in new service of the heat itself, which he balked it, or getting a LP furnace, which he still balked at.

So my question is how accurate are the load calculations and how should I handle this costumer who is balking at doing it right, especially after I did the rewrite of the rest of the house?


“ shoot low boys their riding shetland ponies”
 
When you add the load of the man cave does it go above 200 amps? If it does tell him he is over the limit. Have you considered a high efficiency heat pump? That should lower the total load compared to electric baseboard heat
 
mkgrady said:
When you add the load of the man cave does it go above 200 amps? If it does tell him he is over the limit. Have you considered a high efficiency heat pump? That should lower the total load compared to electric baseboard heat
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Yes it does. Told him he’s at that limit every time we talk or text, told him in March when I roughed in the place “you are pushing your load limit” so I would hope he knows by now. we are in Northern WI so a heat pump is not a option, not a fan of them anyway


“ shoot low boys their riding shetland ponies”
 
When you are adding on NEC has multiple methods for doing load calcsfor existing loads. One of them is collecting data for at least 2 weeks. This is far better than the standard or alternative methods that both are simply estimates vs. actual data. But carefully read the requirements on the actual load method. The goal obviously is to deliver a working system that meets Code and doesn’t nuisance trip.
 
McLintock said:
Have a costumer that as a all electric house, as a 20kW furnace. Wired in the house and he is right at 160 amps (200 amp service), now he is turning the garage into his “man cave” and is insisting on baseboard heat in there to have on when he is not there (it’s a 2nd home).
Click to expand...

Does that mean that the customer will not be using the house during the colder part of the year when the baseboard heaters will be operating? If so then the load of an electric range/stove would not be present when the baseboard heaters are activated, at least for the present owner of the house. Perhaps there are also other loads that would not be present when baseboard heat is being used.
 
synchro said:
Does that mean that the customer will not be using the house during the colder part of the year when the baseboard heaters will be operating? If so then the load of an electric range/stove would not be present when the baseboard heaters are activated, at least for the present owner of the house. Perhaps there are also other loads that would not be present when baseboard heat is being used.
Click to expand...

Customer will be up here in the winter as he is a snowmobiler, he as two 5.9 kW ranges. I have a feeling the baseboard heat will be used more than when he’s not there, as this guy forgets conversion we have had in the past few months.


“ shoot low boys their riding shetland ponies”
 
synchro said:
Does that mean that the customer will not be using the house during the colder part of the year when the baseboard heaters will be operating? If so then the load of an electric range/stove would not be present when the baseboard heaters are activated, at least for the present owner of the house. Perhaps there are also other loads that would not be present when baseboard heat is being used.
Click to expand...
Sounds like some the cabins I have worked in where there is possibly some significant heating load when not occupied, but at same time little or no other load when not occupied. If heat is needed when occupied they have wood stove or fireplace that usually is burning. Very possibly can get away with adding the load in question and never trip the main in that sort of situation.
 
Although it's not really a good solution, one could tell the customer that he cant use the range and baseboard heaters at the same time. Considering that the customer is forgetful, that limitation could be enforced by a DPDT switch that feeds either the range or the baseboard heaters but not both at the same time (i.e., a transfer switch but for two loads instead of two power sources). Of course the customer probably wouldn't like this approach either because he wants everything. ;)
 
synchro said:
Although it's not really a good solution, one could tell the customer that he cant use the range and baseboard heaters at the same time. Considering that the customer is forgetful, that limitation could be enforced by a DPDT switch that feeds either the range or the baseboard heaters but not both at the same time (i.e., a transfer switch but for two loads instead of two power sources). Of course the customer probably wouldn't like this approach either because he wants everything. ;)
Click to expand...

Yes, he wants it but wants it done as cheaply as possible. Every house we take care of up here that’s all electric as two services, one for heat and one for everything else. This house has one 200amp service and has a 150 amp breaker coming off the 200 amp panel that goes to a meter, owned by the POCO to feed the furnace and hot water heater. So it’s not right at all, probably shouldn’t have touched it in the first place.

Just told the customer that I would not feel comfortable adding any kind of electric heat to the load of the service and gave him my reasons. Told him “you know you can get a second opinion” and he agreed, so I may not have to worry about this anymore


“ shoot low boys their riding shetland ponies”
 
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