Against Code to Put Three Stoves on 100 Amp Breaker Service?

Quackerjack

I currently have two stoves and a washer/dryer on my 100 amp breaker panel.

I want to add a third stove in the basement. I know that if I have all three stoves running at max at the same time (or two stoves and the dryer), that it will trip the main 100 amp breaker. But is it against any electrical codes to have the third stove (220 volt outlet)?

I would have to do this via an added subpanel.

AllanJ

The three stoves per se are not against any code but you need to do a load analysis (see the NEC for the procedure). Load analysis includes suche things as 3 watts for every square foot, so many watts for air conditioners (see specifications or name plate), so many watts for clothes dryer, multiply some items by a derating factor for those items not on for long periods of time (continuous/intermittent), etc. When the load analysis comes up with a number larger than your service (100 amps; 24,000 watts) then you would need to upgrade your service. Using a subpanel does not change the need for or results of a load calculation.

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The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.

stickboy1375

How did you come to this conclusion?

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Quackerjack

Two electricians and a random realtor told me this but they could have been wrong ... They did happen to be insisting that the only solution would cost about $4000 to increase the service to 200 amps.

Do you have differing knowledge? I would assume this is just a matter of math but I have no idea how to calculate this.

Quackerjack

Okay, I get it now that the total load calculation vs the 100 amps is the pertinent factor (not the fact of 3 stoves). Now, does it matter if it is a single family using these various appliances/loads, who can monitor that the appliances are not all used simultaneously? Or is it a blanket rule that the load calculation must be done with blanket percentages for usage and if that is over the 100 amps than I go to jail?

I've never had the main breaker flip with my existing setup (2 stoves and a dryer) but IF it did on the extremely rare occasion with 3 stoves, I think I could live with it.

I guess the important thing is what's the worst that could happen? I understand the breaker trip. Anything else dangerwise? Is it really a big deal? Would the code police come after me? Or more practically, if I later sold the house -- will a building inspector raise a red flag?

AllanJ

If you install wiring (or anything else) in violation of code (including ignoring results of a load calculation), one or more of the following bad things might happen:

1. In case of fire or other casualty the insurance might not cover.
2. When you sell the property the buyer might find the problem (maybe with the help of an inspector) and the sale would fall through.
3. Following a surprise inspection the property may be condemned until you fix not only the code violation you created but also other items.

The load calculation must be done using blanket percentages. Note that a third stove may tip off the building inspector to see whether things look like an illegal in-law apartment within your house.

The story was told that a certain buyer and a certain seller signed a purchase and sales agreement with the usual "subject to inspection" clause. During inspection a problem was found (with the furnace, not the electrical system) and the buyer called the building inspector who promptly condemned the building until a new furnace was put in. The seller was unable to back out and the buyer completed the purchase with the new furnace courtesy of the seller.

__________________
The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.

Quackerjack

Allan, you've answered all my questions. Thanks a lot for the help.

In the end, I've decided that the best solution is to get a gas line run for the stove on the second floor. Natural gas is more cost effective anyway and this avoids potentially overloading the 100 amp service and tripping the main breaker in the future and any of the other associated problems.