200 Amp Service Clarification

From Internachi’s How to Perform Residential Electrical Inspections

Other training books also discuss the concept that a homeowner would need/want a 200-amp to support a “modern lifestyle”. In addition there was a thread a few weeks ago about another inspector who had a client upset over if he had a 200 AMP service or not.

My question is, is a 200-AMP service really necessary?

Even with computers, flat screen TVs, cell phones on chargers and such, most electronic devices and appliances use less electricity than the previous generation of devices and appliances. In addition, CFL and/or LED lightbulbs draw less power.

In my own home, I have a wife and 2 kids with all the electronic gadgets that seems to accompany a full family, plus AC, pool plump, 2 refrigerators, etc. All running on 100 amp service with no problems. With changing my light bulbs and energy efficient appliances, my electrical use is down from where it used to be, even though I have more stuff plugged in these days.

Granted, we have gas stove, gas over, gas dryer, gas furnace and gas water heater, as is common in California.

So is the thinking that someone needs a 200 (or more) amp service an out dated concept with energy efficient appliances?

Or is more a regional thing that’s only needed where gas appliances aren’t present?

Ian, I think more than geographical, it’s the amount of gas appliances that are “normal”, or whether a client prefers electric for whatever reason.

Just one of your gas appliances being changed to an electric one would likely justify the need for at least 150 amp service.

Gas is plentiful in most places here, but some clients don’t want gas. I prefer it myself.
In fact, a client just last week wanted me to check if installation of an electric range was possible, she wanted to remove the gas range already in place. She didn’t like cooking with gas. The furnace was gas, and the dryer and water heater were electric. There had been a gas water heater before, because the abandoned vent pipe was still through the ceiling and in the attic, and the gas pipe was still present. Somebody probably needed a water heater, and electric ones are much cheaper, lighter, and easier to install.

I don’t “call out” 100 amp service, but I do recommend upgrading to 150 or 200.

I only call out less than 100 as some insurance companies have denied coverage unless an upgrade was performed.

Mike is correct, different areas of the country have different appliances. When you consider an electric furnace, water heater, A/C, dryer and range might all be present in some homes, 200 amps makes sense. It also allows the home to handle future power needs if they materialize.

Thank you Michael and Cameron.

The modern versions of the NEC require a minimum of 100 amps for a single family dwelling which is probably adequate if all of the heating and cooking appliances are gas and the house is a modest size. Truth is you’ll never really know unless a calculation is performed. IMO a 200 amp service is a cheap insurance policy in case things change in the future, like the house is expanded or the owner wants a new 50 amp hot tub.

My son recently bought a house that was built in the 50s with a 100 amp service. It was a federal Pacific fused service panel and my recommendation was to upgrade it to a 150. He has central air conditioning and one to 2 outlets in each bedroom. The kitchen counter had one double outlet to run the toaster and mixmaster that they had back in the 50s. Now in the kitchen we have cappuccino/espresso machines, microwaves, convection oven, mixers, Electric knives, fondue pots, electric stove , Range good and double oven. And that’s without being a gourmet chef.
My son contracted with electrician to install a 150 amp service and the electrician told him that he should upgrade to a 200 amp service because it only cost an additional $200.
I do not have gas at my home where I live and it’s an 1800 square-foot house with central air conditioning and oil heat. I have a 200 amp service and a generator because occasionally the electric goes out. The kitchen range takes 50 A the air-conditioning takes 30 A the dryer takes 30 A the water heater takes 30 A the sewage pump takes 40 A and on it goes! That’s 180 A if they are used to their maximum without even starting the other outlets. I have a sewage pump because I am downhill from the sewers that are in the street.
I would assume that each of the circuits are designed to have an excess of electricity going to that appliance so that no problems occur. I would much rather be comfortable with my electrical service then considerate strained.
Now you mention the larger homes with multiple air-conditioning systems, heating systems multiple laundry areas and is 400 A excessive? Absolutely not!

I have a 400 amp service. It’s full. I don’t have room for another breaker.

If you’re a hobbyist and weld you could consume a tremendous amount of power. I live in central New Jersey where many of the estates have 5 to 10 car heated garages!
Certainly a house that’s 1000-2000 sq.ft. A 100 A Service is most likely adequate if you don’t have a garage. If you’re smart and conserve electricity you can certainly make it on a 100 amp service. But it gets right down to “different strokes for different folks”

Adding up the breaker handles is meaningless. It is only a math exercise.

Simply because a panel is full does not mean you are out of capacity.

Adding up breaker handles gives us a general idea of approximately the potential electrical usage within the home. Of course all circuits are not going to be working at full capacity at any given time but, it gives you a general idea of electrical usage potential, without doing ridiculous math calculations what the power consumption potential is. Without doing a “math exercise” how can you judge what the potential usage of electricity is in the house?

Most homes could get away with a 50amp service. NEC load calcs are highly conservative. The NEC minimum service for dwellings is 100amps, and is sufficient in most cases. What determines the need for a larger sized service are load calcs. Adding up breaker handles is meaningless, I could have 200 circuits in a home, as long as the calculate demand of all those appliances doesn’t exceed the service I am ok.

Jim and Robert are correct, you can’t, without actually measuring load.

Just because the range is on a 50 amp breaker, doesn’t mean it will ever draw 50 amps. Maybe 1/2 of that.

Same with 30 amp water heater breaker, dryer circuit, and so forth.

I have measured all electric homes with everything running at the same time, and measured about 93 amps.

Granted, I couldn’t run heat and a/c at the same time, but nobody does that anyway.

It’s kind of like a car engine that is capable, and registered for 130 mph. It will likely never happen.

Mike, I sincerely appreciate your input! I have one question. I am not electrician and I would have no idea of how to measure that Amount of electricity to discern the usage in a home as you did. How was that accomplished?

Charles, I used to install back up generators at homes, hospitals, colleges, etc., so load calculations and measuring were part of my tasks.

It is done with an amp clamp meter, which is very expensive, and miles beyond the scope of a normal home inspection.

So, again, just adding up the breaker capacities is pretty futile. One example: My living room is all on one 20 amp circuit. There’s probably never a time when there is more than 4 or 5 amps on that one circuit.

That’s why we just “generalize”, and say that homes should have at least a 150 amp service.

I knew that we did not use the total amount of amperage that each breaker, on each circuit can handle. I was merely using the calculation, as horribly rough as it was, as a rough justification to upgrade from a 100 amp service to at least 150.

There’s nothing wrong with your method, Charles, as a HI.

It’s all in the wording. If you count those up, and come up with 190 or 200 amps, then state it “needs to be upgraded because the total is XXX”, then a sparky will come and throw you under the bus.

Nothing makes a contractor feel bigger and better than throwing a HI under the bus.

You’re absolutely right!
I like the Sparky referral! Thanks for your help sir!

Always glad to help out a NACHI bro’ in need.

There are plenty of more experienced homies on this mb who are just as eager to lend a helping hand. :smiley:

I agree with the electrician, $200 for an extra 50 amps is a no brainer. I would never install a 150 service as an upgrade unless the client insisted on it. Truth is if the electrician buys the 200 amp panel at a big box store he will save quite a bit over the cost of the 150 amp panel at the electrical supply house. The cost for the installer in material is almost the same for a 150 and 200 amp.

Agreed. “It’s better to have it and not need it, than need it and not have it” :smiley: