Pull Power from House or New Service?

[duwem]

17 year old house with 200amp service.
House electrical draws: 120v: Drier, fringe, washing machine, dishwasher lights; 220v: range oven, well pump, central AC
Shop: 120v: lights(likely led), garage door openers, cieling fans, power tools; 220v: lathe, mill, 6hp air compressor, Car lift, 200amp Tig and mig welder, boiler for in floor heat.

As it will be mostly me working there wouldn't be running more than 2-3 big things at a time unless buddies come over to work on stuff.

Electrician said they can put a 125 amp breaker in my house panel and put a sub panel in my shop.

Is the 200 amp enough?

Electrical company said $15 a month fee for a second meter, and that could go up in future. They would hook the power from pole to shed for free I believe.

Growing up when my dad would strike an arch on the old tomb stone Lincoln stick welder the house lights would dim for a second. But they might have less than 200 amp.

 

[wyliesdiesels]

I suspect 90a would suffice.

I would avoid the second service as it will add up over time.

A branch feeder will pay for itself...

 

[ard]

This isn't a 6000 square foot beast with multiple AC units, right?

200 should be adequate - and give the loads you described for the shop, 90 will work- and depending on the distance, might save a bit with wire size/cost.

Sounds like an electrician doing this? Useful to get educated as to options instead of just going with their plan.

One comment on the second service- some Pocos will charge a higher rate on the second meter. So the monthly fee could go up, or in the future you could find the outbuilding charged at a higher rate. (I've also seen where some can get a second service to an "AG Building", and they pay less...)

 

[ticklechicken]

I would avoid the second service as it will add up over time.

A branch feeder will pay for itself...

I assumed the same thing, but I got a different answer from my power company. My monthly fee for the meter is $7, but the first 1,000 kWh is at a reduced rate (for each meter). The end result is that if I use over 400 kWh in the shop, it's cheaper to install a second meter.

I haven't received my first bill yet, so we'll see if it really works out like this.

 

[duwem]

Parts and labor:

125amp pulled from house, trenched to shed, 125 amp, 40 circuit panel in garage, grounded per code. $2350

200amp meter pedestal, 200amp 40 circuit panel in garage, grounded. $925. Run service from pole to meter $311. $0.15 a day second meter fee forever(rate could go up in future). Same kw/hr rate as primary service to house.

 

[wyliesdiesels]

Why 125a?

 

[mike93lx]

200a is plenty.

My house has 100a service. Two fridges, a freezer, 2 ton a/c, dryer, well pump, plus the toys in my garage. Based on what you listed, i would feed from the house (90a) without thinking twice. No need to pay for another meter.

Drop that 125a to 90 or less so you can use much cheaper 2-2-2-4 mhf. You'll save a lot on wire

 

[duwem]

Why 125a?

125 is the max single circuit they can add to the house breaker box.

It's only 60' of wire between the two can't imagine the cost will chance that much for larger wire, but I could ask.

 

[ard]

125 is the max single circuit they can add to the house breaker box.

It's only 60' of wire between the two can't imagine the cost will chance that much for larger wire, but I could ask.

I'm guessing Wylie is thinking smaller....

You can DIY? Or is that $2300 not really a concern?

Of all the DIY tasks in the construction world, electrical service work is some of the most cost effective

 

[alexb2000]

I changed my meter base out for a 400 amp. Kept the same single meter and now I have 400 amp service and a second panel for the garage. Pretty simple operation and then you don't have to worry about running out of power.

I don't know if every area supports that at the transformer, but it might be an option.

 

[wyliesdiesels]

OP doesnt even need 400a though.

No need to add to the cost.

KISS

 

[mushia]

200a is enough I think.

 

[mike93lx]

I changed my meter base out for a 400 amp. Kept the same single meter and now I have 400 amp service and a second panel for the garage. Pretty simple operation and then you don't have to worry about running out of power.

I don't know if every area supports that at the transformer, but it might be an option.

Was that just a nice to have or did you actually do load calcs to justify that upgrade? You must have some very high demand loads in both the house and shop.

 

[Matt Matt]

I changed my meter base out for a 400 amp. Kept the same single meter and now I have 400 amp service and a second panel for the garage. Pretty simple operation and then you don't have to worry about running out of power.

I don't know if every area supports that at the transformer, but it might be an option.

I have a feeling the power company's transformer feeding you (and possibly others) will not give 400a.

That size transformer is about half the size of a minivan. It's not one of those ones that would hang from a pole. It would need to be close to 100 kVA and it would be sitting on your front lawn. You would have to assume if there's not one on your neighbours front lawn, they're sharing yours. The pole size ones are 15 kVA and 25 kVA. One is about twice the size of a 5 gallon pail and the other one would be the size of a large 40gallon garbage pail respectively.

 

[ard]

I have a feeling the power company's transformer feeding you (and possibly others) will not give 400a.

That size transformer is about half the size of a minivan. It's not one of those ones that would hang from a pole. It would need to be close to 100 kVA and it would be sitting on your front lawn. You would have to assume if there's not one on your neighbours front lawn, they're sharing yours. The pole size ones are 15 kVA and 25 kVA. One is about twice the size of a 5 gallon pail and the other one would be the size of a large 40gallon garbage pail respectively.

Huh

Do a search for 100kva pole mount transformers.

What do you think they mount n poles to feed 2,3,4 homes each wtih 200A services??

 

[ForceFed70]

When faced with the same choice, I pulled power from the house. My PoCo wants $24/month just to send me a bill for the 2nd service.

200A is plenty. 100A service for the shop is plenty for a 1 man operation. You can only use so many tools at once.

 

[Matt Matt]

Huh

Do a search for 100kva pole mount transformers.

What do you think they mount n poles to feed 2,3,4 homes each wtih 200A services??

I know they have them, but what I'm saying is traditionally most homes do not have more than 25 KVA each. I know for a fact that I share a 50 kVA with three other neighbours. When I dim my lights on a hard motor start, I know my neighbours lights are dimming too. So I am splitting 210 A with three neighbours. The power co. won't put in a larger transformer usually, until they experience problems with their fusing switch. The larger 100 kVA pole transformers are usually three phase step down on the main.

 

[ard]

That size transformer is about half the size of a minivan. It's not one of those ones that would hang from a pole.

I know they have them, but what I'm saying is traditionally most homes do not have more than 25 KVA each. .

Im just going by your post- you said it WOULD be the size of a minivan, and 'not on a pole'.

I pointed out they do make them to hang from a pole (I have one).

 

[dscheidt]

Im just going by your post- you said it WOULD be the size of a minivan, and 'not on a pole'.

I pointed out they do make them to hang from a pole (I have one).

My house, and two or three of my neighbors, and the alley street lights are on a 100 KVA transformer on the pole by my garage. It's about 4 feet tall, and maybe 2 feet in diameter, judging it against the bucket they used to work on it.

 

[DC73]

I swapped my meter base to a 320 Amp base. Those bases have two sets of load lugs. One for the existing service to the house and one for the new service to the shop. Only one meter necessary. This turned out to be the best deal for my situation.

DC

 

[wyliesdiesels]

I have a feeling the power company's transformer feeding you (and possibly others) will not give 400a.

That size transformer is about half the size of a minivan. It's not one of those ones that would hang from a pole. It would need to be close to 100 kVA and it would be sitting on your front lawn. You would have to assume if there's not one on your neighbours front lawn, they're sharing yours. The pole size ones are 15 kVA and 25 kVA. One is about twice the size of a 5 gallon pail and the other one would be the size of a large 40gallon garbage pail respectively.

Maybe thats what your PoCo has. But around here, a 100Kva pole pig is NOT half the size of a mini-van.

My PoCo and the other large PoCo in the state have single phase pole pigs up to 100Kva.

And Ive seen transformers, feeding several houses, sized anywhere between 25kva and 75Kva. 25, 37.5 and 50 being the most common.

However, The only time I see 100Kva single phase cans is when theyre part of a 3 phase bank. But they by themselves are single phase.

My buddy who is a lineman and works for the local PoCo, says their engineers typically under size the required transformers...

 

[ard]

My buddy who is a lineman and works for the local PoCo, says their engineers typically under size the required transformers...

Yeah, and undersize the wires to feed the meter too.

'Code is for the pussies on the other side of the meter....

 

[wyliesdiesels]

He said They use to oversize them but to save on costs they now undersize them.

BTW PoCos arent governed by NEC code.

 

[dscheidt]

He said They use to oversize them but to save on costs they now undersize them.

BTW PoCos arent governed by NEC code.

When they were regulated, most utilities were allowed to generate a certain return percentage on installed capital. So spending more on capital equipment meant they made more money, which provided an incentive to oversize. (they'd also face scrutiny if they had too many outages...) Deregulated, they don't get the guaranteed return (nor the scrutiny for outages...), so the incentive is to go cheap.

My PoCo apparently engineers service drop size based on house square footage, which means I have a 6 gauge aluminum triax. Looks pretty silly connected to the 4/0 that feeds the meter.

 

[barnee]

I swapped my meter base to a 340 Amp base. Those bases have two sets of load lugs. One for the existing service to the house and one for the new service to the shop. Only one meter necessary. This turned out to be the best deal for my situation.

DC

Ditto for me. Another issue was if they ran a new service they only do it underground and wanted a 15' easement from the pole to my garage, and the path would have been very damaging to my landscaping.

 

[Matt Matt]

Maybe thats what your PoCo has. But around here, a 100Kva pole pig is NOT half the size of a mini-van.

My PoCo and the other large PoCo in the state have single phase pole pigs up to 100Kva.

And Ive seen transformers, feeding several houses, sized anywhere between 25kva and 75Kva. 25, 37.5 and 50 being the most common.

However, The only time I see 100Kva single phase cans is when theyre part of a 3 phase bank. But they by themselves are single phase.

My buddy who is a lineman and works for the local PoCo, says their engineers typically under size the required transformers...

we mainly have pad transformers like this. Maybe these styles are cheaper.

 

[Norcal]

The OP is wanting 125A, there is a considerable difference in price between 80-100A, breakers & 125A breakers, + wire costs. It is doubtful 125A is needed.

 

[Bert_]

The OP should look at the loads that could run at once instead of just guessing at a feeder size. Nothing wrong with going a little oversize if you think you might add load later.

Definitely need to know a size on the boiler if it is going to be electric.

we mainly have pad transformers like this. Maybe these styles are cheaper.

It just depends on whether the primary is overhead or underground in your area. Obviously underground primary would have pad mount transformers while overhead would use pole mount transformers.

Even a 167kva (which i believe is the largest 1 phase transformer) is not the size of a minivan.

 

[wyliesdiesels]

I swapped my meter base to a 340 Amp base. Those bases have two sets of load lugs. One for the existing service to the house and one for the new service to the shop. Only one meter necessary. This turned out to be the best deal for my situation.

DC

you sure its not a 320a meter base?

Never seen a 340a meter base...

 

[wyliesdiesels]

we mainly have pad transformers like this. Maybe these styles are cheaper.

We have those too but mostly only for 3-phase service.

Still those arent close to mini-van size.

Even the very large 480Y pad mounts arent close to mini-van size.

Single phase ground transformers are actually in an underground vault.

 

[Matt Matt]

I do thoroughly enjoy when I say "HALF" the size of the minivan (and I may have been exaggerating a wee bit) those who can quote me and say "it's nowhere close to the size of a mini van". They seem to forget "HALF even when they quoted me. Pretty tough crowd when they like to change your words.

My initial point was when someone upgrades their 200a service with a Second 200a service to their shop and if they are sharing 100 kVA transformer between them self and three other neighbours that each have a 200 amp service, additively that is 1000 A. I was just suggesting you're never going to get what you pay for, unless you demand the power company to put in your very own transformer. I have heard in some situations the power company forcing the upgraded purchase of transformer on the customer. Maybe those who have won the battle with the power company upgrading transformer for free and chime in.

 

[duwem]

Shop boiler would run off propane just like the house furnace and water heater do.

The OP should look at the loads that could run at once instead of just guessing at a feeder size. Nothing wrong with going a little oversize if you think you might add load later.

Definitely need to know a size on the boiler if it is going to be electric.



It just depends on whether the primary is overhead or underground in your area. Obviously underground primary would have pad mount transformers while overhead would use pole mount transformers.

Even a 167kva (which i believe is the largest 1 phase transformer) is not the size of a minivan.

 

[Dragfluid]

For grins, I just went out and looked at mine. When I started my first business here on the farm, I turned my 3 HP compressor on and watched the lights pulse with each stroke of the pump. Went in the house, and the TV was dancing across the floor. The TF was the original one put in when electricity was first invented out here. A phone call resulted in them coming out in a very timely manner and swapping it out for something a little more modern. That was 44 years ago. Now even though we shouldn't pay attention to labels I am pretty sure that where you see the shadow of one on there it said "10". Does that sound about right Wylie?
I didn't have a minivan for comparison handy, but I think that the wife's Trailblazer is close.

 

[DC73]

you sure its not a 320a meter base?

Never seen a 340a meter base...

You are correct. Fat fingered that one. I've corrected my original post.

DC

 

[nsula_country]

I have a feeling the power company's transformer feeding you (and possibly others) will not give 400a.

That size transformer is about half the size of a minivan. It's not one of those ones that would hang from a pole. It would need to be close to 100 kVA and it would be sitting on your front lawn. You would have to assume if there's not one on your neighbours front lawn, they're sharing yours. The pole size ones are 15 kVA and 25 kVA. One is about twice the size of a 5 gallon pail and the other one would be the size of a large 40gallon garbage pail respectively.

This is funny!

I have a 400 amp service at our house, 50 kVA pole mount. Shop has 200 amp service, 25 kVA pole mount.

CT

 

[Matt Matt]

This is funny!

I have a 400 amp service at our house, 50 kVA pole mount. Shop has 200 amp service, 25 kVA pole mount.

CT

That is interesting. For those in the know, a 50 kVA transformer, what is the maximum amperage it can produce at 230-ish volts?

S(kVA) = I(A) × V(V) / 1000 or
I(A) = 1000 × S(kVA) / V(V)

 

[wyliesdiesels]

50Kva is about 217a @ 230v.

 

[Matt Matt]

50Kva is about 217a @ 230v.

So, if he's pulling 250 A for more than a minute, will the fusing trip at the transformer or at his main first?

 

[barnee]

Apparently transformers can be way overloaded. My pole mounted transformer is a 15Kva and serves two houses each with 200 amp service.

My new loads add an additional 200 amp to that transformer and the power company is going to swap that out with a 100Kva transformer.

Tell me that wasn't overloaded

 

[nsula_country]

50Kva is about 217a @ 230v.

I'm assuming it's a 50kVA, it has a sticker on it that says "50"... Engineer said it was a 50 kVA. At 240V a 50 kVA is rated 208 amps.

I know I can pull over 250 amps easily in the winter with (2) 27 kw water heaters (1) 3.5 ton HP with 15 kw resistive (during defrost mode only) and (1) 2.5 ton HP with 10 kw resistive (defrost). Not to mention electric cooktop, ovens, dryer and household loads. Never checked voltage drop though with everything churning.

I know how to size a xformer. I question the POCO all the time about their sizing. They fall under a different play book because it's all "open air" so I've been told. POCO rarely sizes their primary xformers as we are required to size our secondary xformers. At least in our area...

Pissed me off when they required me to use 500 MCM copper and they used a 4/0 Al drop...

CT