Electric service question

Bryan W M

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Oct 31, 2011
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Getting electricians to agree is about like asking who makes the best action.

I’m putting up a shop . 32x36 lights, outlets ,over head doors and an outlet for welder . I have 200 amp service now . House is all electric.
I had two electricians come out.
One said I need a split 200 amp meter the other recommended getting 400 amp service. With the house being all electric I think the 400 amp might be wise.
I didn’t get the warm fuzzy feeling with either electrician that made me want to trust them.

So what says the few electricians on here.
 
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my cousin had a 360 amp service put in for his house which is around 2800sf I believe and he has a 40x60 shop.
I'd do the 400 Amp panel. Keep in mind the meter will be a 320 Amp meter. In order to do a full 400 Amp you would need a commercial panel with CT's . Realistically, in a home with a separate large shop you'll likely never get close to maxing out the 320.

ETA I'm not an electrician. I'm lineman for the power company.
 
From your description it sounds like both agreed you needed a dedicated 200 amps to the shop on top of the 200 for your house…

There are reasons to do it both ways, for example a separate meter will probably cost you more per month (base charge for the meter). However the utility may pay the wire to the shop thus saving you installation costs.

If you were to run a business out of the shop you would want a separate meter. If it’s just your storage and work area it’s nicer on one service.

You are just looking at 2 different solutions to one install. Either way you’re going to end up with a separate 200 amp panel in the shop.
 
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How are they proposing to split your 400A service?

I have 400A at my house through 1 meter pan the utility said could handle up to 600A. It splits out to two disconnects that run to two separate 200a panels in my garage. I plan to run 100A from one panel out to my shop when I build it as I figure that will be plenty.

Your existing meter pan can PROBABLY handle 400A unless its really old(doubtful since it seems all the utilities want to be on smart meters) and then they can simply pull off of it to a disconnect and then pull off of that a 200a panel in your shop. Might need to breaker it in the disconnect depending on code requirements before the underground run.
 
Do the 400. Upsizing the service likely wont be that much more.

Interesting how different areas do different things. When we put ours in power co asked if we wanted a 200 or a 480. I did the 480 since it wasn't that much more and seemed like a no brainer. The 480A service was a meter with 2-200's and an 80. The 80A ended up going to a small panel on the pole. I put a 50A rv hookup there and ran a 30A to the greenhouse.
 
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Remember, you're one person, so you can only do so many things at one time.

Call the utility and tell them you want the peak KW for your house over the last two years. Not peak KW/hr, but peak KW. Youll need the meter number.

200Ax240V= 48KW
400Ax240v= 96KW

You can at least see where youre at.

Most utility companies hang a 15-25KVA transformer on a pole for residential. You might get a 400A panel, wires, but there might only be a 25KVA transformer on the pole feeding it. A utility will drive them to 125%, so that would still be your limitation. Unless you can quantify more load, they likely wont change that transformer.

Most main breakers are not continuous duty, so whatever service you have is really only good for 80% of that.

A one man shop is not likely to use over 200amps.

If a contractor adds loads in Amps and not KW or KVA, then they havent a clue.
 
Ok so I spoke with the power company.
They can do a what they said is 200 amp meter with two breakers in it one for the house one for the shop.
My other option is upgrading to 400 amp service that sounds like a new transformer and a new meter again with two breakers.
That is what I got from the power company.
They also want to move the meter from the house to the pole. That means the underground wires they put in in 2014 would now be my problem….
They will only put the 200 amp meter with the two breakers on the house will not do the 400amp that has to move to the pole..

This is becoming a can of worms.
 
Most utility companies hang a 15-25KVA transformer on a pole for residential. You might get a 400A panel, wires, but there might only be a 25KVA transformer on the pole feeding it. A utility will drive them to 125%, so that would still be your limitation. Unless you can quantify more load, they likely wont change that transformer.

When I talked to the utility before I built this house the guy didnt tell me what KVA transformer was installed(he might not have known without doing some research), but said they use "smart" transformers in that they report the load and if, between my neighbor and I, we were consistently getting close to 100% they would come put a larger transformer in. I asked "how much does that cost me" and he said "thats my problem at that point"...
 
Have you considered a seperate service entry for the home and shop. Is there a reason they need to be connected?

Keeps you from dicking with any of the existing at your home and allows you to go ham at the shop. But as mentioned above the Transformer might be a limiting factor if you wanna max out both .

I am not an electrician. Just a suggestion.
 
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Have you considered a seperate service entry for the home and shop. Is there a reason they need to be connected?

Keeps you from dicking with any of the existing at your home and allows you to go ham at the shop. But as mentioned above the Transformer might be a limiting factor.

I am not an electrician. Just a suggestion.
This. Both bills can be added to your existing account number. We have 5 meters at my bakery. We get one bill
 
Have you considered a seperate service entry for the home and shop. Is there a reason they need to be connected?

Keeps you from dicking with any of the existing at your home and allows you to go ham at the shop. But as mentioned above the Transformer might be a limiting factor if you wanna max out both .

I am not an electrician. Just a suggestion.
In our service are you pay a charge per meter. I believe it's about 30 bucks a month. Not huge but adds up. Lots of companies don't do that....worth checking on.
 
Not sure of your location.

In my neck of the woods, as an electrician (I even got a license out of a box of Cracker Jacks,) I have seen your basic 200 amp and 320 amp and I have seen 1,600 amp with switchgear on a gigantor house and gigantic pool in Dallas, Texas. The power company never gives your full calculated load. I learned that from doing a building that had 4 units with 100 amps each in Lewisville, Texas.

Texas - New Mexico power came out and pulled wire that I knew was smaller than 400 amps worth. He said they provide roughly 67% of your calculated load. 1of the reasons, you will never run AC and heat at the same time because of thermostatic controls. Electricity is one of the resources that has to be generated on demand. We don't have batteries big enough or enough african slaves to mine the materials for batteries that big.

But yeah, ask for the biggest you can get. And realize that it can get expensive.

With one builder, they had a client that were two homersexuals that bought a house in a rural county and wanted to get away from that ugly old propane (no natural gas in that area.)

They wanted to go "green" and get a 150 amp electric heater for the pool/spa system. Well, by golly, the house panel was loaded and the service was 200 amps. And, most importantly, the transformer feeding that neck of the woods did not have the ampacity to boost up that house. The nearest pole they could get the additional 150 amps was a mile as the crow flies and no way to by right of way.

But hey, at least they had butt sex and felt good about trying to "save the environment" by causing the possibility of carving more land and more wire and more power generation.

See, just because a guy can suckle upon a penis does not make him smart or wise or all that good for the environment.

This has been my Ted Talk.

Edited for numerical accuracy.
 
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Go with the 400A main panel in the house, with a 200A breaker feeding a panel in the shop. With that you’re covered all the way around. Put a main breaker in the panel in the shop for safety reasons.
Agree 100%. Grew up in the busines (didn't do design work but I did sleep at HI express in a college town once or twice) and we had a 400 Amp main for the house, no shop but I'd want the shop on a separate service/panel anyway for a multitude of reasons.
 
Lineman for 18 years.

Doubt very seriously you need more than one 200amp service to run it all.

Just because you have 200 amp worth of breakers, or a 200amp panel doesn't mean you will ever draw that much. Are you going to have everything on at one time with a blow dryer in every outlet? No. I have a 200a main at my meter feeding 2x 200amp panels and a 100amp sub panel and have never kicked the main. My house is 4300sq feet, and have a shop with 2 welders, lathe, mill, 2 post lift, and heat. Am I going to be running the lathe, while tig welding and have the air compressor running at the same time? Nope.

Best way is to put an amp meter on your existing service and see how much power you draw regularly or power company van probably tell you if you have an AMI meter. If your not pulling over 100amps regularly I'd just put a disconnect below your meter and feed garage from that. If your house has a newer high sear hvac and led lighting I'll bet you aren't using much.
 
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Lineman for 18 years.

Doubt very seriously you need more than one 200amp service to run it all.

Just because you have 200 amp worth of breakers, or a 200amp panel doesn't mean you will ever draw that much. Are you going to have everything on at one time? No.

Best way is to put an amp meter on your existing service and see how much power you draw regularly or power company van probably tell you if you have an AMI meter. If your not pulling over 100amps regularly I'd just put a disconnect below your meter and feed garage from that.
So, say the old lady is doing laundry in her electric dryer....kids upstairs playing games on puters, you in garage using stick welder on RV that is plugged into 50A service (along with welder) and just then someone kicks in the microwave.
Not a rare scenario, but you'll be very close to 200-250 amps right there.

Now the 220V air compressor kicks in.

Well.......
Shit.
 
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You probably don’t need a 400A service but if it were my house and all electric I’d probably go with the upgrade to 400. I serve my shop with a 100A sub panel from my 200A main panel but I’m all gas in the house. 100A is plenty for my shop. Lights are about 2kW out there. I’m using that plus one machine or welder at a time. Compressor kicks on once in a while but it runs for about 60 seconds.
 
BTW, I could certainly be wrong about this......but I *think* NEC will no longer allow a smaller than 200a on a home and if the shop is above a certain size, same.

Like I said....I'm not sure.
If someone has the new books take a gander plz.
 
So, say the old lady is doing laundry in her electric dryer....kids upstairs playing games on puters, you in garage using stick welder on RV that is plugged into 50A service (along with welder) and just then someone kicks in the microwave.
Not a rare scenario, but you'll be very close to 200-250 amps right there.

Now the 220V air compressor kicks in.

Well.......
Shit.
Exactly.....you don't need to just get by. More is better.....if nothing else, having the extra breaker space makes life easier in the future. Helps with resale value as well. When the 2 homo's mentioned above need to charge their electric cars.....they'll need the extra capacity.
 
So, say the old lady is doing laundry in her electric dryer....kids upstairs playing games on puters, you in garage using stick welder on RV that is plugged into 50A service (along with welder) and just then someone kicks in the microwave.
Not a rare scenario, but you'll be very close to 200-250 amps right there.

Now the 220V air compressor kicks in.

Well.......
Shit.
Well, in my opinion, that's kinda a rare scenario there. You weld on your RV quite a bit? Lol. Just a joke.

Seriously though, even with all that on at one time you MAY be on the upper end, but not likely if you do an actual load reading.

When I started my career we put in 320/400 amp services all the time at residential homes, and it's honestly pretty rare anymore. Everything in a home is so much more efficient these days, that the load is just not there.

To each thier own, I'm just trying to save the guy some money. If he is wanting to upgrade a 320a meter base is way more than enough. They still have 2x 200a breakers in them.
 
So, say the old lady is doing laundry in her electric dryer....kids upstairs playing games on puters, you in garage using stick welder on RV that is plugged into 50A service (along with welder) and just then someone kicks in the microwave.
Not a rare scenario, but you'll be very close to 200-250 amps right there.

Now the 220V air compressor kicks in.

Well.......
Shit.
You're still not going to get close to 200amps with that!

Dryer = 6KW
Welder = 11kw
Microwave = 1.5kw
Air compressor (1hp)= 2KW

I come up with 31.5KW. 48KW - 31.5KW = 16.5KW left. 16.5KW/240V= 68.75 amps left. The reality is, that the FLA/KW info on all appliances is based on the very, very, very worse case condition, so you're really about 1/2 of what is published. So, you're still using only about 15KW. 15KW/240V = 62.5amp, a far stretch from 200amps. The worse case condition on a residential service is when you start motor loads at the exact same time, which never happens! Motor loads pull 8-12X the FLA on start up. That is why they have capacitors in them, give the little extra push when needed.

No residential home/shop is going to use 200amps, just not gonna happen! If you do trip a main, it will be once or maybe twice in a life time. However, contractors love to spend your money!

Now, if you have super big machines in your shop, probably a different story. Again, one man can only operate so many machines at one time.

There is a reason the utility company only puts a 15-25KW transformer on your pole or in the little pedestal in your yard.
 
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200amps is plenty. If you want to worry about anything, I would worry about the distance from your utility/home to the shop and make sure your electrician is looking at voltage drop. The other thing, is making sure he is doing the grounding electrode system properly! I would spend the extra money you save sticking with your 200amps and add surge protection on your panels.
 
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Yeah I’ve put a meter on my wires coming in with a compressor running in the shop and all lights on with an electric oven on and was only around 50 amps or so, you might pull around 100 on occasion but you would have to have everything going at the same time, like mentioned above it’s the start up load that pulls the most amperage.
 
In my neck of the woods, as an electrician (I even got a license out of a box of Cracker Jacks,) I have seen your basic 200 amp and 320 amp and I have seen 600 amp with switchgear on a gigantor house and gigantic pool in Dallas, Texas.
You never installed a 600Amp piece of switchgear. You might have installed a 600amp switchboard or large panelboard, but you didn't install switchgear! Switchgear is about $25K per cubicle, the breakers are about $25K each. Those breakers are draw-out style and rated for 65-100KA of fault current.

Sorry, I usually try to avoid these electrical threads, as the asinine info in them drives me nuts, and I hate arguing on the internet.
 
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Electrician and welder here,

the only reason to run a 200 amp service to your garage is if you are planning on welding aluminum, and thick aluminum at that. if you are a hobby welder, think anything below 200 amps(welding amps) only pulls 54 amps out of an inverter based machine, the old tombstones or transformer wound machines will pull more but I don't see you welding with 5/16ths rod.

I ran my entire house, and my garage off of a 200 amp service and I welded professionally for years, if I had anything big or thick I'd run my engine drive and it would push 300 amps all day.

that said, after wiring and building several garages, my ideal setup for any climate would be a 100 amp sub panel with propane 99+ EFF furnace, and maybe a 3 ton ac unit for cooling should you require it.

the 400 amp service be it a 400 can or a 320 can doesn't matter, you will likely never come close to pulling 200 amps regardless unless you have 2 hot water heaters, Tesla charger, and base board heaters along with 15kw heat strips in your air handlers... so without a full audit of what you have I couldn't make a professional judgement, but I do install upgraded services frequently, 1 out of 10 or so, switching from 200 to 400 because they both bought teslas etc...

BIGGEST thing in my opinion is run a copper 2/0 to your garage to reduce voltage drop. one thing people don't realize is that most small houses have around 3000 feet of wire in them, it averages out to 2 feet per square foot usually, and that length has resistance, any load that is always on in your house, is always going through a resistor, and creating heat out of your money, so upgrade your wire size on ANY LOAD that is always running, fridge, ac, lighting circuits that are always on, and you will see a difference in your bill, and it will continue to pay for itself for the entire time you own your home. this is especially true for hot water heaters, etc...

that said a "SENSE" device from amazon will help you determine your actual KW load and KWH through the day, I have one, love it, simple to install, easy to use,,,... look it up, little red box


AND finally, SQUARE D equipment is the best for homeowners hands down, homeline or QO,doens't matter,homeline has a nicer neutral bar setup, but qo is industrial grade sort of. "caveat there,,, won't get technical here"


PM with questions if you really want to chat otherwise Cheers!!!
 
Electrician and welder here,

the only reason to run a 200 amp service to your garage is if you are planning on welding aluminum, and thick aluminum at that. if you are a hobby welder, think anything below 200 amps(welding amps) only pulls 54 amps out of an inverter based machine, the old tombstones or transformer wound machines will pull more but I don't see you welding with 5/16ths rod.

I ran my entire house, and my garage off of a 200 amp service and I welded professionally for years, if I had anything big or thick I'd run my engine drive and it would push 300 amps all day.

that said, after wiring and building several garages, my ideal setup for any climate would be a 100 amp sub panel with propane 99+ EFF furnace, and maybe a 3 ton ac unit for cooling should you require it.

the 400 amp service be it a 400 can or a 320 can doesn't matter, you will likely never come close to pulling 200 amps regardless unless you have 2 hot water heaters, Tesla charger, and base board heaters along with 15kw heat strips in your air handlers... so without a full audit of what you have I couldn't make a professional judgement, but I do install upgraded services frequently, 1 out of 10 or so, switching from 200 to 400 because they both bought teslas etc...

BIGGEST thing in my opinion is run a copper 2/0 to your garage to reduce voltage drop. one thing people don't realize is that most small houses have around 3000 feet of wire in them, it averages out to 2 feet per square foot usually, and that length has resistance, any load that is always on in your house, is always going through a resistor, and creating heat out of your money, so upgrade your wire size on ANY LOAD that is always running, fridge, ac, lighting circuits that are always on, and you will see a difference in your bill, and it will continue to pay for itself for the entire time you own your home. this is especially true for hot water heaters, etc...

that said a "SENSE" device from amazon will help you determine your actual KW load and KWH through the day, I have one, love it, simple to install, easy to use,,,... look it up, little red box


AND finally, SQUARE D equipment is the best for homeowners hands down, homeline or QO,doens't matter,homeline has a nicer neutral bar setup, but qo is industrial grade sort of. "caveat there,,, won't get technical here"


PM with questions if you really want to chat otherwise Cheers!!!
The ONLY good thing about my cookie cutter. Square D. The wiring itself is shit! Sure, they saved money; but it looks like a rat was in the attic. That said, I have ONE spare breaker slot (200 Amp service). And I do trip one breaker all the time in a house built in 2007. Same one...it's the garage and outdoor plugs.

A buddy of mine and his wife were looking at houses and asked me to look at things before they even got a home inspection. First thing I noticed...Square D QO Load Center. I was like 'I hate you.' :). That's what we had and I can tell you that only ONE breaker failed in 50 years!!! And, truthfully, I'm not sure it really failed or not it was right when my father was near death and I didn't question it.
 
I have a pole by my property that feeds the house and barn (barn is a workshop). Both have a 200 amp service. The meter base has two 200 amp breakers so I can shut off power to one or the other (that's handy). Six years ago, they installed this for free.
I quit my IT job to build the house and barn.

I'd get one of these installed if you could, lots of flexibility.

IMG_20241119_085550572.jpg

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IMG_20241112_162940530.jpg


IMG_20241119_090941465.jpg
 
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Like others have said, the 320a feeding a 200a panel in the shop and the 200a in the house.
Going to a 400a is a huge jump, I did one for a client about a year ago. They wouldn't listen and were insistent on the 400 over the 320. From the meter socket to the shop was over $10k and the utility company hit him for another $15k. Then on top of that considered it a commercial account and charge him demand even on a single phase service.

Milbank 320a meter can, with 2 200a disconnects, or a disconnect and feed through panel. one to the house one to the shop. This arrangement is half the price of buying a 320a with the two integrated disconnects. Which is about $2k for the Miilbank and the Square D is about the same price.

In reality if it's just you, lights, welder, compressor, misc plug in tools you could run a 125a service to it and be fine. My buddies last shop has a 125a service, we have run multiple welders, plasma cutter, compressor, lights....
KW load and demand with the welders and plasma cutter is intermittent.
My current shop has a 320a feeding it with a 15hp VMC, 15hp turning center, 10hp compressor, 5hp surface grinder, plasma table, welding gear, air conditioning...
Peak demand is about 60kW (about 250a depending on where power factor is)
 
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Ok so got a hard number from the power company. The 200 amp meter with two breakers will be free. They said can only have 100amp service off it for the shop.

The 400amp service 2 200 amp breakers installed is 1200 .
I’m leaning this way.
The house is all 12 wire on basic circuits.
You add in the dryer, electric heat, stove , microwave, lights, air compressor welding.
I have 3 boys and another kid in the oven so it won’t be just me in the shop .

For 1200 I think it’s a good investment for long term use of my place.

Ok I keep seeing you guys say square D for the panel?? @Kinetic Moose
Is there a specific panel you would recommend I’ll be buying from Lowe’s .
 
You never installed a 600Amp piece of switchgear. You might have installed a 600amp switchboard or large panelboard, but you didn't install switchgear! Switchgear is about $25K per cubicle, the breakers are about $25K each. Those breakers are draw-out style and rated for 65-100KA of fault current.

Sorry, I usually try to avoid these electrical threads, as the asinine info in them drives me nuts, and I hate arguing on the internet.

Most times MDPs are referred to as switchgear.

The duplex's I'm doing right now are 800A services with MDPs. 5 200A 40 space panels. All pretty much full.

They're also 8000sq ft, have multiple boilers, 4 furnaces, multiple shower steamers, etc.