Question about electrical load calcs and service upgrades

[aunsafe2015]

My house currently has 200 amp service. I'm thinking about converting some gas appliances to electric and am wondering if doing so will require me to upgrade to 320 or 400 amp service to pass inspection.

Dehumidifier 700W
Washer 1200W
Dryer 7200W
Oven 5400W
Microwave 3300W
Induction Stove 11500W
Dishwasher 1150W
Refrigerator 200W
Disposal 1200W
Heat Pump #1 7100W
Heat Pump #2 (mini split) 1500W
Heat Pump Water Heater 4500W

Total: ~48,000W / 240v = 200 amps

The wattage values above are all from the face plates of the appliances. I don't know if all of them need to be included in the calculation or not but I've listed them all here. The above list might also be missing certain things that DO need to be included (lighting?).

Anyways, what I'm curious about is whether the above load would require me to upgrade to something bigger than 200 amp service.

If not, how high would my load need to be before code WOULD require me to upgrade? Would adding an electric car charger (10,000W) require me to upgrade?

Thanks for any input. I know code differs slightly from AHJ to AHJ but I'm interested in hearing what's typical/common.

 

[sberry]

I was told there wouldn't be any math. There will be someone along soon to help.

 

[Stuart in MN]

There are any number of service size calculators and tutorials online, I'd run the numbers through a couple of them to see if I could get consensus (just do a search on "service size calculator"). This the first one I found: http://www.nojolt.com/load_calculations.shtml This article by Mike Holt is useful as well: https://www.ecmweb.com/national-ele...ing-unit-feederservice-conductor-calculations

 

[aunsafe2015]

There are any number of service size calculators and tutorials online, I'd run the numbers through a couple of them to see if I could get consensus (just do a search on "service size calculator"). This the first one I found: http://www.nojolt.com/load_calculations.shtml This article by Mike Holt is useful as well: https://www.ecmweb.com/national-ele...ing-unit-feederservice-conductor-calculations

Thanks.

Does anybody know how likely an inspector is to actually ask for a load calc? I mean, suppose I replace a gas cooktop with an induction cooktop. The induction cooktop may have a VA rating of 10,000, which is obviously much higher than a gas cooktop.

So you do things by the book, get a permit for your new 240v circuit to feed the induction cooktop, and have the inspector out to sign off.

Is a typical inspector going to ask to see the load calc to show that 200 amp service is still enough for your house with your new induction cooktop? Or is he simply going to look at the 240v circuit that you added and call it a day?

 

[wyliesdiesels]

The inspector may not look at it but most PoCos require it.

 

[aunsafe2015]

The inspector may not look at it but most PoCos require it.

PoCos require it for what? I think they'd require it if I was asking to upgrade from 200 to 320, but I'm not. I actually affirmatively do NOT want to upgrade and I'm trying to figure out how likely it is that I would be required to do so even though I don't really want to.

Last time I added a 240v circuit to my house (for a mini split) the power company wasn't involved at all...?

 

[alfredeneuman]

Does anybody know how likely an inspector is to actually ask for a load calc?

The inspector doesn't ask for the load calc. If it is it then will be required when the plans are first submitted. It's up to the people in the plan check and approval dept.

 

[sberry]

If you wanna do a change from 200 to 400 they wanna know. I dont know anyone up the food chain but if I ask nice can meet or talk to the engineer and his notepad and we can decide how we want something done. The lineman was surprised they had said to bring another wire, says we hook to the old one all the time. It wasnt that old but it wasnt the same as what I got spec.

 

[sberry]

You got a couple greedy items, most noteable the heat pump and a greedy dryer. A 50A cook but thats wide open and runs on 50A service. About like a spin in the hot tub but shorter, real load likely 1/2 that for long if ever more than that.
Gas is nice in electric outage and it takes the peak off your electric. You have some large pieces could add an extra 20 to the real load if they on the same time. 4500 water heater is modest and a normal dryer is low 20s. This could give a 100 a healthy workout. Would improve things if the microwave was 240V

 

[sberry]

I am not sure why I would want to simply change the gas to electric , rewire it all, upgrade the service, add some astronomical expense if I was getting along. They make nice gas **** too.
I would be glad to do this job if you got your heart set on it though. I have seen some bars and restaurants really baking, a couple people couldnt oprorate that much ****.

 

[sberry]

Had 1000A of breakers on a hot wall in a 200 panel. Outside brown wall. I turned a fan on it, started it in orderly fashion and took the cover off. The owner was fond of electric fryers. They had built a Friday night biz. There musta been half a dozen 50A appliances to it and working and another 50 in cooling. Plus the exhaust and about a dozen other circuits loaded with small appliances.

 

[sberry]

I wasnt a sprout but I had some history with these people and had sobered up, they paid me decent to help and they pulled a permit thru a cousin was a contractor and a retired fireman bud was a customer of the place was a journeyman and him and I did the better part of an uprgrade and put a new 325/400 base and ran a pipe around to another wall and plumbed a 150 on it.
Was simple really, was some attic and the new box was closer and we climb up and connect some load over. We did the conversion with the poco while they wait and the inspector was an old bud type thing he hung out for lunch and actually watched the hookup.

 

[wyliesdiesels]

PoCos require it for what? I think they'd require it if I was asking to upgrade from 200 to 320, but I'm not. I actually affirmatively do NOT want to upgrade and I'm trying to figure out how likely it is that I would be required to do so even though I don't really want to.

Last time I added a 240v circuit to my house (for a mini split) the power company wasn't involved at all...?

yes thats what i meant. They will require it if youre upgrading which you alluded to possibly needing.

i would do a load calc and go from there.... they are not hard at all.

Mike Holt has a good one. Just plug in the numbers and it spits out the answer

 

[mcbane]

My microwave is only 750W and takes forever to do anything. Where do you get the 3300W unit, and is it 240v? Do you have a link?

 

[aunsafe2015]

My microwave is only 750W and takes forever to do anything. Where do you get the 3300W unit, and is it 240v? Do you have a link?

It's one of the microwaves with a built-in resistance/convection heating element. Something like this: https://www.kitchenaid.com/major-ap...-oven-with-convection-cooking.kmbp107ebs.html

So my guess would be that the 3300W is not solely for the microwave. That would probably be if it was using the microwave and the resistance heating element at the same time.

 

[alfredeneuman]

I noticed you entered 7200W as the Dryer Load.
It comes out to 30A at 240V (which is the common c/b size for a clothes dryer)
Dryers draw 21-22A. Loads are figured according to the actual nameplate rating of the appliance (not the breaker size)

 

[Terry D]

Is your heat gas or electric

 

[alfredeneuman]

Is your heat gas or electric

They're heat pumps and therefore electric.

 

[Aceman]

What is the square footage of the home?

 

[wyliesdiesels]

My microwave is only 750W and takes forever to do anything. Where do you get the 3300W unit, and is it 240v? Do you have a link?

I have a 1200w inverter model from Costco. It kicks ***.

If i dont pay attention, I overcook the food. I always have to take time off the stated minutes on the package. Otherwise it will be burnt