Will your home inspector tell you if your electric service is too small?

30 amp service

While it goes beyond the scope of a home inspection to perform load calculations, occasionally I'll practise a crude calculation if I become concerned that an electric service is too modest for a house.  If the service size from my crude calculation comes up too close to the bodily service size, I'll recommend having an electrician perform an official load calculation... and I call up I've done this twice.  Ever.

At most every home inspection, I find one of two things:  either the electric service is outdated and manifestly besides pocket-size, such as the 30 amp service pictured at right, or the service has been upgraded or over-sized and is enough big plenty for the home.  I don't find much in-between those two.

I got to thinking about this while inspecting a 3,600 sf house in Plymouth for an old friend from loftier school.  This home had a 100 amp electrical service, which seemed too pocket-size for that size of a business firm.  I considered recommending an electrician to do a load calculation on the firm, merely I first plugged in a few numbers at an online load calculator - http://www.electricalknowledge.com/SFDLoadCalc.asp .

I didn't have all of the exact numbers that I needed, so I guessed on a bunch of them, such as the VA ratings on the garage door openers, garbage disposer, dishwasher, and microwave.  I put in 1800 VA for each ane of these, which is certainly way also loftier, simply it makes me experience ameliorate virtually guessing - at least I'm not guessing on the low side.

This dwelling house was heated with a gas furnace, had a gas wearing apparel dryer, a gas h2o heater, and a gas oven.  The only major 240 volt appliance at this home was the air conditioner.  This is pretty common for a home in Minnesota.

Can you guess what the calculated service size was?68 Amps.

Granted, my adding probably wasn't perfect, and I'm not certain that this online load calculator was completely accurate, merely this was enough to make me non worry almost the service size.  When I took an electric inspection class many years ago, we had to perform a lot of load calculations for fictional houses, and I learned enough to know that if most of the major appliances are gas, a 100 amp service is probably plenty enough.

I invite y'all to plug in the numbers from your own home at the online load calculator that I linked to to a higher place - you might exist surprised at how small of a service you could actually get away with.  For the tape though, the smallest commanded service for a new home today is 100 amps.

Reuben Saltzman, Structure Tech Home Inspections - Email - Plymouth Home Inspector

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