200amp vs 400amp service?

[Itsjustdirt]

Our friends are having a new main panel installed. Their house is roughly 2500sq ft with a detached 3 car garage/shop. They are planning on building a 1200sq ft guest house in the near future. I suggested they have a 400amp panel installed but their electrician is talking them into a 200amp panel. He says 200amps is plenty for everything, even including their future guest house plans. Does that sound right? The workshop has a 50a welder plug, 30a compressor, and a bunch of power tools that use a decent amount of electricity. I figured his workshop should have a dedicated 100amps, the main house 200amps, and future guest house 100amps. Is this really overkill?

 

[strength_and_power]

I don’t have a house but I’ve read a lot of the threads here so I will take a stab at it.

Location?
Heater/ clothes dryer? Gas or electric?
How many people working in Shop at once?
Welder probably won’t be running WFO while compressor is going and the shop heater is going full bore as well.
Guessing the jump in price from 200 to 400 is well over double and probably not worth the extra expense for the ultra slim chance that much power is actually needed.


Sent from my iPhone using Tapatalk

 

[Viper98912]

In sum, 200+100+100 does seem fairly reasonable and conservative. At the same time, 400 in general does sound pretty large...

 

[Norcal]

Load calc's are what will dictate if 400A is needed & adding the sum of the breakers is not a load calc, in all reality residential loads are low.

 

[peter2772000]

Here in Quebec, a 400A entrance allows access to the input power before the meter. I know of a few people, in mostly rural areas, who'll connect to this power source and heat a garage all winter long for free.

I'm not condoning this, just mentioning it in passing...

 

[BillK]

Dirt,
Without knowing the exact uses i would say 200 should be plenty. My house is 2000 sq ft and I have a detached 24x24 garage. House has a 200 amp panel and the detached garage is fed off it to a 100 amp sub panel. I still have a bunch of open slots on the house panel. I also have natural gas heat and hot water so the only "large" loads in the house are the oven and the clothes dryer and ac in the summer.

I imagine if you had a well pump, electric heat and hot water etc then it may be a different situation.

 

[CraigStu]

We are in the beginning stages of building a 2400 house w/ 3 car attached garage in southern Va. I don't know any details yet but builder did mention he will use a 400 amp panel. 2 heat pumps, 2 electric ovens, electric drier, but propane ranges and water heater.

 

[wyliesdiesels]

Here in Quebec, a 400A entrance allows access to the input power before the meter. I know of a few people, in mostly rural areas, who'll connect to this power source and heat a garage all winter long for free.

I'm not condoning this, just mentioning it in passing...

It sounds like youre referring to CT metering.

Tapping into the power before a pass through meter is not really any different.

 

[sberry]

I don't do this 50 weeks a year butbit isn't my first rodeo as they say. I have only seen a couple overloaded panels in my career. A 60 fuse on a house that had all electric appliances and a 200 in a tavern that had way more than you could cram in a house. I have never taken a call for overloaded 100 in a home, I am tied on to 100 from my Dads all electric.
You rePly have to crank to get near heating up a 200. They barely add much to a load calc for a garage as it is so intermittent.

 

[yeldogt]

Our friends are having a new main panel installed. Their house is roughly 2500sq ft with a detached 3 car garage/shop. They are planning on building a 1200sq ft guest house in the near future. I suggested they have a 400amp panel installed but their electrician is talking them into a 200amp panel. He says 200amps is plenty for everything, even including their future guest house plans. Does that sound right? The workshop has a 50a welder plug, 30a compressor, and a bunch of power tools that use a decent amount of electricity. I figured his workshop should have a dedicated 100amps, the main house 200amps, and future guest house 100amps. Is this really overkill?

Stove/Oven/AC/Heat Pump (3T and above)/Dryer -- for a typical house all four can be a stretch. Three no problem. Electric heat changes the formula ... and if NG available ... for dryer and heat ....200amp is plenty.

 

[joe_padavano]

load calc's are what will dictate if 400a is needed

^^^this!

 

[ForceFed70]

Like others - we need more info. If it's heated by gas and doesn't have a huge cooling load, then it may be fine.

Here's a comparison - had a house with a 2 bedroom suite in the basement. 2 of everything, 2 kitchens, 2 laundry rooms, etc. Central air with gas heat. Also had a 2 car garage with welder plug that would often be used for my powder coating oven.

That house had a 100A service and never tripped the main once in the 6 years we lived there.

My understanding is that a 200A service doesn't cost a lot more than 100A, but making that next step to 400A is significantly more expensive.

 

[FANTM58]

I just finished my new house and detached Shop build
House is 4000 sq’ plus 1000 sq’ attached garages
And a 2400 sq’ shop 40’x60’
200 amps each
400 main service split 50/50

 

[macdabs]

In my area the 400 amp is the way to go if you have what I call above average hobby shop . It is easier to sub off a 320/400 amp meter base to separate panels. Most of your 320/400 amp meter bases have two sets of feeder lugs for two 200 amp sub panels. The cost is around $150.00 more than a standard single 200 amp base . The cabinet has more room and the power company is responsible for the feed to the meter for the demand.
The problem is not the continuous draw . The issue is your surge draw on startup and your loss in distance to your sub panels. If your compressor in your shop kicks on at the same time your welding in the shop. Plus the home heat pump ,refrigerator and well pump kick on your lights will flicker. You also need to consider the feeder distance from the transformer to the meter base and your loads. It is far cheaper to install a 400 amp service in the beginning than later . Having separate panels off a 400 amp service gives you the ability to add and service a panel off and still have a power source from the other panel.

Mac

 

[jim111]

In my area the 400 amp is the way to go if you have what I call above average hobby shop . It is easier to sub off a 320/400 amp meter base to separate panels. Most of your 320/400 amp meter bases have two sets of feeder lugs for two 200 amp sub panels. The cost is around $150.00 more than a standard single 200 amp base . The cabinet has more room and the power company is responsible for the feed to the meter for the demand.

Mac

This is how it is in my neck of the woods also. Do more of these than 200 amp anymore because of the available expansion especially larger homes with multiple outbuildings. Utility charges 200 dollars more for 320/400 service build than 200 amp. This is not a true 400 amp which is ct metered here and much more expensive build. I don't know exactly what the OP is describing, and they may not do the 320/400 meter setup in his area

 

[sberry]

Something to consider a bit is that if one wants to use backup power 400 may add to the complexity.

 

[driftpin]

Here in so. Florida, I inspected luxury homes by GL Homes, among others. They build $1 million+ homes, and the larger 5000-7000 sq. ft. homes would use two 200 amp panels.

I recall one buyer from So. America couldn't close for a month. The house was completed, and the builder ran the AC and pool and spa as-if someone was there. The electric bill for the month was $1500! That's what the project manager told me when I was doing a final inspection for my discipline.
http://longlakeranches.net/

GL builds a quality home, and they have several developments currently in Palm Beach Co. FL. https://www.glhomes.com/

 

[peter2772000]

It sounds like youre referring to CT metering.

Tapping into the power before a pass through meter is not really any different.

Whazza CT metering?

 

[wyliesdiesels]

Whazza CT metering?

Current transformer.

 

[walta]

Whazza CT metering?

CT = Current transformer

With Ct meter the power does not flow thru the meter. The meter is connected to remote current transformers one for each power conductor the power wire passes thru a hole in the thansfomer and sense the current flow in the wire.

 

[tarmy]

I have two meters...1 each for 200A...

I needed to set a new transformer for my initial 200A panel in my 3200 sq ft shop. Since I was trenching for a new future home and the shop...the power co only charged a couple hundred more for the transformer and extra drop to my meter panel.

From the main street panel I ran two 3" conduits to each of the new structures.

My 200A panel in the shop is totally full...

Do the calcs., run the costs, anticipate the future expansion plans and size accordingly...

 

[theoldwizard1]

I have a neighbor who is a sparky. He bought a "distressed" house in the neighborhood, CHEAP !! He replaced a "not to code" addition on the house, built a 2.5 car, extra deep, as tall as allowed by code, garage and lots of other improvements. He could afford all of this because of the cash he got out of the sale from his other house.

I was over at his place last year and he was out back behind the garage doing some wiring. He had 2 huge disconnect panels, 200A each, one for the garage and one for the house ! I asked him about the feed from the pole and he smiled. His only comment was, "I have climbing spikes" and "What the electric company doesn't know won't hurt them". (I assume that means he replaced the feed himself.)

I don't know how that much power is metered in a residential area !

 

[sanddan]

The 200 amp panel in my shop is full, I even have 2 spaces filled with 4 thin breakers for extra circuits. I've been welding when the furnace is running and had the compressor kick on so it happens. 200 for the house and 200 for the shop seems correct to me.

 

[peter2772000]

And here I was, thinkin' I knew it all LOL.

Thx to you both!

 

[nsula_country]

Load calculation will show if really needed.

All electric vs gas appliances will also dictate service size.

I was fine until we decided on tankless electric water heating... Two 27kw units, 2 heat pumps, 2 electric furnaces, double oven, electric cooktop, electric dryer and future shop. Installed a 320a meter pan with two 200a 3R feed thorugh panels. The tankless water heaters pushed me over the 80%/200a.

Then built the shop 300 yards away and went with a dedicated 200a service for it.

CT

 

[wyliesdiesels]

Load calculation will show if really needed.

All electric vs gas appliances will also dictate service size.

I was fine until we decided on tankless electric water heating... Two 27kw units, 2 heat pumps, 2 electric furnaces, double oven, electric cooktop, electric dryer and future shop. Installed a 320a meter pan with two 200a 3R feed thorugh panels. The tankless water heaters pushed me over the 80%/200a.

Then built the shop 300 yards away and went with a dedicated 200a service for it.

CT

Geez your electric rates must be REAL low.

 

[nsula_country]

Geez your electric rates must be REAL low.

House averages under $200 month.

CT

 

[wyliesdiesels]

House averages under $200 month.

CT

Ouch

Whats your Kwh rate?

 

[nsula_country]

Ouch

Whats your Kwh rate?

Closer to $120 average if not too cold and HP runs exclusivly w/o frequent defrost cycles in our short winter. 10kw and 15kw resistive heat. No LEDs... All incadescent cans, 65w.

I'll shoot you kwh and fuel surcharges.

CT

 

[nsula_country]

Ouch

Whats your Kwh rate?

Closer to $120 average if not too cold and HP runs exclusivly w/o frequent defrost cycles in our short winter. 10kw and 15kw resistive heat.

16 SEER single stage HPs. AC cycles even in our hot, humid weather due to good insulation to keep hot out and cool in.

No LEDs... All incadescent cans, 65w. 44 of them, 10ft ceilings, 31 6ft tall windows, 5 exterior doors. Spray foam insulation.

I'll shoot you kwh and fuel surcharges.

CT

 

[nsula_country]

Looking at shop bill, paper copy. House is online billing and beautiful wife handles it.

Rate billing, $24.63
Fuel surcharge, $0.0307610/kwh, $9.20
Fed EAC, 0.0006500/kwh, $0.19
Line extension, mo/5 years, $95.06

Don't see a monthly min or meter fee... May be in line extension...

$129.08... $34.02 actual bill minus line extension (700+'). 299kwh in February.

About 0.11/kwh?? At shop... Ag/commercial meter. Think house is under residential rate.

CT

 

[All]

A neighbor got a tankless electric hot water heater, did the current calculations, and determined he needed to upgrade his panel to 400A. He did so, using a licensed electrician, who pulled a permit and got inspections. It all passed, so he turned the water heater on. Circuits all over the house went out, without any breakers being tripped. Dimmer switches in his media room were ghosting lights on when they should have been off.

Many hours of head scratching later, they called me over to look at it. It was a beautifully big electrical panel. I was quite envious. Then I asked them if the power company had upgraded the drop from the power pole on the street to their house. Nope, they said. I responded by suggesting that since their house was built before WWII, it could be that the drop is inadequately sized to support 400 amp service.

I heard the next day that after the power company was contacted, they sent a crew out that very night, and spent all night restringing a new power line drop from the pole to the house to feed the 400 amp panel. End of problem.

I'm not a licensed electrician. I don't know what made me think of the drop from the pole being inadequate, other than homes did not have the same kinds of electrical demands 75 years ago as they do today. But, if you do get a 400 amp panel, give some consideration to the capacity of the cables feeding your house, no matter if on a pole or underground. Get the power company to make the determination, if necessary.

 

[ard]

Get the power company to make the determination, if necessary.

A slightly related observation...

I suspect many times the POCO is approached with an 'upgrade' to a 400A service, or new construction- and they simply shrug and size their side of the service using their internal calculations for loads. (ie sqft, heat, AC, other stuff- the standard items they ask about on a new service work order)

Unless you make the case, formally, for how you plan on drawing over 200A, they may not size the service to the 400A you think you are buying.

 

[FTG-05]

When we had our house built in Madison back in '94, we specified another hot water heater supplying the main bathroom only. Because of this, the builder put in a 200 amp CB box and a 100 amp CB box. Virtually every house in that subdivision came with 200 amp CB boxes. This was very useful over the +20 years I owned that house.

So, another option to think about.