200 amp shop? Why not?

[turbowoodworker]

I have a simple question. What are the reasons I might not be able to get 200 amp service to my new build detached shop?

More info: new build 5000 sq ft house with attached 3 car, 400 amp service to house. Service line not yet run from street.
Detached 1200 sq ft shop for wood working, metal/welding etc. and have poured thick concrete and high trusses for a lift.

Met with electrician today with the GC and was told I could only get 125 amp service to shop with 400 amp service to house. This statement without a good answer came when I asked for an automatic transfer switch for a future generator. Also told I'd be "OK" with 125 amps even though they didn't really listen, know or understand my list of existing tools (Lincoln 180c/220, 220 compressor, 220 cyclone dust collector, future 220 table saw). Nor did they factor in my planned lift, 220 minisplit(s) or plasma cutter, etc. I know in a one man shop I will not use 5 tools at once but I will use the dust collector with the TS, or the compressor with the lift, etc. does the request for a future generator impact the answer?

Am I asking too much? Since the line isn't yet run from street should I ask for 600 amps to house? Second service meter? Or just second opinion? Or should I "settle" for 125 amps in my dream shop?

Thanks in advance. While I can't change GC this far along, I am not married to this electrician...yet.

 

[larry_g]

Some of the decision lays with the power company. Start there. They may not have the capacity to deliver and restrict the user to some maximum.

lg
no neat sig line

 

[pete379]

buddy of mine did exactly that. built house,400 amp service, a few years later, built shop, 200 amps at shop,from house
pete

 

[OldNeons]

I have a 325 amp main service/meter socket that splits at socket and supplies two 200 amp panels. One in house that will have sub panel for attached 3 car garage w/ bedrooms over. 2nd 200 is in barn and subfeeds the machine shed. Power company said if I want o expand again they will have to upsize the pole mounted transformer. I'm hoping to get them to switch new transformer to underground and run another separate 325/400 service to my future shop building which will feature plenty of heavy draw tools/machinery. Wish I could get 3 phase here!

Long way around to say,you only want to do this once. As mentioned above start with power company, and I would even go so far as to "overstate" your needs as who knows what you may want in the future. It's not going to cost them much more and you are paying it one way or another in the end.... I'd push for a separate shop service.

 

[ddawg16]

200 Amps is a lot for a shop.....unless your going to have more than one person doing stuff at the same time....you will never use that much power.

I have 50A going to my garage....it was 30....and I never hit that limit.

IMO....it's just a waste of copper....

 

[tfi racing]

All valid points,but if you want 200 amps to your shop,have the ability to pay for it and the poco will provide it-go ahead and spend your money!

 

[OldNeons]

All depends on what you are planning, and how that might change over the years...I know this will be my shop- until I can't "wheel" into one anymore. I will have compressor, welderS, plasma,shear, boiler for radiant floor heat, powder oven, a whole lot of old neon and much more. I've worked in/with too many under sized, underpowered panels and I won't make that mistake. If you work by yourself and won't have much more than your original list you might get by fine with 125, but I'd want a 200 for what YOU are doing. And two of them for me

 

[theoldwizard1]

While I agree with ddawg16 (welcome back), I can think of no "logical" reason for not allowing 200A to your detached shop. With a 400A feed from the power company, there should be no issue.

I would split the incoming line at the meter. Separate disconnect may be required.

 

[MTW]

A few pointers...

1st. The National Electric Code (NEC) normally has a basic requirement of only one service per property, under a single management, regardless of the number of structures. There are exceptions, usually requiring special permission from the utility and inspection authority.
Verbiage:

230.2 Number of Services. A building or other structure
served shall be supplied by only one service unless permitted
in 230.2(A) through (D). For the purpose of 230.40,
Exception No. 2 only, underground sets of conductors,
1/0 AWG and larger, running to the same location and connected
together at their supply end but not connected together
at their load end shall be considered to be supplying
one service.
(A) Special Conditions. Additional services shall be permitted
to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of
supply for the purpose of enhanced reliability

(B) Special Occupancies. By special permission, additional
services shall be permitted for either of the following:
(1) Multiple-occupancy buildings where there is no available
space for service equipment accessible to all occupants
(2) A single building or other structure sufficiently large to
make two or more services necessary

(C) Capacity Requirements. Additional services shall be
permitted under any of the following:
(1) Where the capacity requirements are in excess of 2000
amperes at a supply voltage of 600 volts or less
(2) Where the load requirements of a single-phase installation
are greater than the serving agency normally supplies
through one service
(3) By special permission

(D) Different Characteristics. Additional services shall
be permitted for different voltages, frequencies, or phases,
or for different uses, such as for different rate schedules.
(E) Identification. Where a building or structure is supplied
by more than one service, or any combination of
branch circuits, feeders, and services, a permanent plaque
or directory shall be installed at each service disconnect
location denoting all other services, feeders, and branch
circuits supplying that building or structure and the area
served by each. See 225.37.

2nd, Calculated Connected Load, Listing square footage and tooling types is pretty meaningless in calculating your actual connected load. Your sparky has to provide a calculated load number and itemized load schedule to both prove that you have the minimum required capacity and that you actually need as much capacity as you are asking for. I won't go into the details, it's probably more than you want to handle, this is what your sparky is for and should know how to do. Your part of it should be to develop a equipment list with every detail for him as a starting point, machine type, voltage, phase, HP, full load amperage, & duty cycle if one is listed. This includes equipment in all buildings and all household loads. This is the basis for getting approval for more service.

The more you can pad this list the more justification you have for a larger service. Don't get too carried away though. Utilities in my area calculate a install charge based on payback assumptions. Meaning they charge an additional install fee over a normal service size, based on how much you claim your going to use versus what your asking for. To get their investment back over time. If you don't use what you claim they will up the rates you pay to compensate, or just charge you for it all upfront. So don't inflate it too much or it will really cost you, or worse they may just deny you the amount of service that you want, calling it unwarranted.

You may be able to get a separate service installed to the shop based on the capacity exception listed above. Maybe even a three phase service if it's not against company policy in your area. If the house calculated load is large compared to their standard service sizes in your area, that could push the justification of a separate service for the shop. Again this all depends on your service provider and local regulations. Just cause you want it, doesn't mean they have to provide it, unless you can substantiate it and pay for it.

3rd. Location of the service disconnects. The general rule of the NEC is to require all service disconnects on a property to be adjacent to each other. This is for fire code reasons. When there is a fire, the fire department needs to kill all power at one location, with no more than 6 operations of the hand. Meaning grouped together and no more than 6 main switches. So picture a large service on the house with a 400Amain disconnect for the house and a 200A one for the shop. Then from there to the distribution panels in each building.

Verbiage:
230.71 Maximum Number of Disconnects.
(A) General. The service disconnecting means for each service
permitted by 230.2, or for each set of service-entrance
conductors permitted by 230.40, Exception No. 1, 3, 4, or 5,
shall consist of not more than six switches or sets of circuit
breakers, or a combination of not more than six switches and
sets of circuit breakers, mounted in a single enclosure, in a
group of separate enclosures, or in or on a switchboard. There
shall be not more than six sets of disconnects per service
grouped in any one location.
For the purpose of this section, disconnecting means
installed as part of listed equipment and used solely for the
following shall not be considered a service disconnecting
means:
(1) Power monitoring equipment
(2) Surge-protective device(s)
(3) Control circuit of the ground-fault protection system
(4) Power-operable service disconnecting means

4th. Generator Hookup. This service location would be the place to install a transfer switch for a generator hookup. You need a large transfer switch here to isolate the utility lines, and connect the generator. This could be manual or automatic depending on your budget, generator type and rating. The transfer switch would need to be rated for the full size of the service if placed at this location, but could run both buildings if required. It's normally cheaper to do it on the original install, than to replace and retrofit everything later.

5th. 125A limitation. This is probably due to one of two things or both.

Load limitation. If the house minimum load calculation is consuming most of the service capacity, then there won't be enough capacity left to supply any additional loads.

Panel Branch circuit size, If your sparky is planning on feeding the shop from the house panel directly, instead of a separate main as suggested earlier. Then there are limitations on the maximum size circuit breaker that can be installed in the panel, depending on the type, size, brand of the panel. Residential type 200A loadcenters usually are limited to a 100A breaker, and that is without using the two spaces directly across from where the breaker is installed. Due to the heat buildup on the busbars. If you have a more commercial 400A or larger panelboard then a 200A branch breaker could be installed.

6th. Cost. All of this equipment can get pricy so do your homework first and make sure you specify exactly what you really need or want. It may behoove you to hire an electrical engineer, maybe through your architect. For him to do the real work and figure out what you need, before you hire a sparky to price or install it. This will cost something upfront, but will go a long way to getting it done correctly the first time. As well as making sure it's code compliant and proving to the utility that you really need a 200A service to the shop.

As a contractor, with a project like this, I won't waste my time pricing a job for a customer if the homework is not done first. If they don't have someone to do it and sign off on it, then I will normally charge them an hourly fee to do it upfront, before I will bid on their project. In this way they can use the info to get other bids and I get paid for my knowledge and time. More importantly when I get the job everybody involved has clear documentation, specifications, expectations and approvals get issued before the install begins. This makes customers happy, prevents changes, delays and cost overruns during construction. Everybody(you,utility,sparky, & local inspector) know what to expect and there are documents to substantiate things if something goes haywire in the process. Nothing worse than having a mad customer that thinks you screwed up wasting his time and capitol, and he owes you a bunch of loot. I prefer to get it right and glean all of the customers repeat business, and referrals. If they don't like to do it this way, I'll pass and let the next guy have the grief and remorse.

 

[turbowoodworker]

Wow! Some great info here thanks to all. Thanks to MTW for the educated and referenced input. I really appreciate that because I can go back to my GC and sub and discuss the possibilities. After I finish putting my equipment list with specs, I suspect that 125 will work. I was just trying to think ahead in case my son wants to buy me that nice giant Miller TIG.

Appreciate all the help folks.

Rick

 

[MTW]

One more thing to consider...

Panel Sizes. Most folks look a panelboard or loadcenter sizes based on amp capacity. However in the real world with most installations, a more important consideration is the number of useable circuit spaces.

Standard panel ampacity's are 100, 150, 200, 400 etc. There is a limit to the amount of circuits that can be legally installed in each size category, and this usually becomes a problem long before the actual amperage capacity is reached in most situations. For standard panels 100A contains 20 ckts, 150A has 30 ckts, 200A has 40 or 42 ckts.

When wiring a shop we tend to want a separate circuit for each piece of equipment, as well as several 120V circuits to separate general use outlets and lighting. When you have 230V 1 or 3 phase equipment, these require multiple slots and eat up the panel space quickly.

So most times it becomes beneficial to install a larger panel than you need to get the required number of circuits for the shop equipment you want.

It is perfectly acceptable to install a 200A 42 ckt panel on a 100A feeder as long as the feeder is protected upstream, at it's source, by a 100A breaker or fuse.

This small additional cost can provide a bit of future proofing for your unknown future additions of equipment, and is worth considering.

Most one man shops will run fine on a 60 or 100A feeder, but usually require more than 12 or 20 ckt spaces for all of the 230V equipment circuits.

Make your load calculations first to ensure you have enough feeder capacity for the planned equipment use. Usually not more than a few pieces at a time. And then count the number of breaker slots that all your equipment, including light and plugs, requires. Then consider the panel size, if you are near full at the time of installation it may behoove you to increase the panel size to accommodate those unanticipated additions before purchasing and installing the loadcenter.

Beware of loadcenters that use 1/2 sized breakers to achieve the rated number of circuits. Regular 2 pole (240V) breakers will eat up 4 of these 1/2 sized slots. 1/2 sized breakers also cost more and generate more heat density inside the loadcenter.

 

[turbowoodworker]

Again, thanks very much. This may be my solution, making sure I have enough spots.

 

[MTW]

As for that giant Miller tig, go with the inverter type. They are smaller, more efficient, run on multiple voltages and phases without rewiring. They also can do stick and mig as well all from the same power source. I bought a used one years ago and one machine does everything I need. Very portable too for field work, designed to fit through a ship hatch by one man...

 

[OldNeons]

One more thing to consider...

Panel Sizes. Most folks look a panelboard or loadcenter sizes based on amp capacity. However in the real world with most installations, a more important consideration is the number of useable circuit spaces.

Standard panel ampacity's are 100, 150, 200, 400 etc. There is a limit to the amount of circuits that can be legally installed in each size category, and this usually becomes a problem long before the actual amperage capacity is reached in most situations. For standard panels 100A contains 20 ckts, 150A has 30 ckts, 200A has 40 or 42 ckts.

When wiring a shop we tend to want a separate circuit for each piece of equipment, as well as several 120V circuits to separate general use outlets and lighting. When you have 230V 1 or 3 phase equipment, these require multiple slots and eat up the panel space quickly.

So most times it becomes beneficial to install a larger panel than you need to get the required number of circuits for the shop equipment you want.

It is perfectly acceptable to install a 200A 42 ckt panel on a 100A feeder as long as the feeder is protected upstream, at it's source, by a 100A breaker or fuse.

This small additional cost can provide a bit of future proofing for your unknown future additions of equipment, and is worth considering.

Most one man shops will run fine on a 60 or 100A feeder, but usually require more than 12 or 20 ckt spaces for all of the 230V equipment circuits.

Make your load calculations first to ensure you have enough feeder capacity for the planned equipment use. Usually not more than a few pieces at a time. And then count the number of breaker slots that all your equipment, including light and plugs, requires. Then consider the panel size, if you are near full at the time of installation it may behoove you to increase the panel size to accommodate those unanticipated additions before purchasing and installing the loadcenter.

Beware of loadcenters that use 1/2 sized breakers to achieve the rated number of circuits. Regular 2 pole (240V) breakers will eat up 4 of these 1/2 sized slots. 1/2 sized breakers also cost more and generate more heat density inside the loadcenter.

THIS ^^^^^^^^^^ is a lot of why I said what I said. Although I did not say it nearly as nicely or completely as MTW (nice work!). After working in a lot of older houses and shops, I am sick of working in under sized (amps or physical capacity) panels. MTW has given you great input, I'd follow it exactly. Wish all subs operated like he does! Have fun building that dream shop!

 

[ddawg16]

Good info MTW......thanks for posting it.

 

[lametec]

As for that giant Miller tig, go with the inverter type. They are smaller, more efficient, run on multiple voltages and phases without rewiring.

They're also a helluva lot more expensive. To replace my giant Airco TIG welder with a new Miller inverter unit would cost $5000, and it still wouldn't have the capacity the Airco does. I paid $200 for my Airco.

200A service would be perfect for me, since the Airco is rated at 104A on 240V. As it is, I only have 100A service, and I put the welder on a 75A breaker.

 

[MTW]

They're also a helluva lot more expensive. To replace my giant Airco TIG welder with a new Miller inverter unit would cost $5000, and it still wouldn't have the capacity the Airco does. I paid $200 for my Airco

I got my XMT 300A unit for $600 used, including a 200A water-cooled torch, added a suitcase wire feeder for I think around $600 new, and a few cabling accessories. 300A is all the power I ever need for my work, and I run it off of 30A 3Phase 240V circuit, that is shared with my Quincy compressor. It was a great investment at that price. I liked it so much that I built a tall cart for it with multiple shelves that fits through a standard doorway, on casters. It holds the power supply, suitcase feeder, metal drawer for accessories, 3 bottles of gas for the different functions, and a transformer and small loadcenter for using a grinder and drill off of the 3 phase power. It's sturdy enough that I can lift it with a fork lift into a plant ceiling to weld there with my standard wire feeder hose when required. And I added a used/ refurbished water cooler unit to the bottom shelf but I rarely need to use that for my work.

 

[James-W]

I have 100 amp electrical service for my house. When I built the garage I called the electric company and asked them if they would run a separate service line to the garage. They said it was no problem and they wanted to know how many amp service I wanted. I asked about the cost for each size service and they said they will run the first 100 feet for free, no matter what size service I wanted. Since the distance for the new service was a little less than 100 feet I had the electric company run a 200 amp service line to the garage. I doubt I will ever use that much power, probably won't use half that much at one time, but the power is available should the need arise. The only extra cost for the larger service was for the larger breaker panel.

 

[turbowoodworker]

Thanks again everybody, and I was only half joking about the big TIG. But I wasn't intending to hijack my own thread. Thanks everybody.

 

[theoldwizard1]

The only SWAG I can think of for NOT allowing 200A to an outbuilding would be local code. Lower power limit would be one way to prevent backyard "manufacturing".

 

[NUTTSGT]

Has the electrician looked at what you are using in the house to make his statement or was it just his "guess" ?

IMHO, I'd be slightly pissed when somebody told me I'd be okay with something, especially if it's not what I wanted. If there's a reason that you can't have it, too much draw in the house, that's one thing. I'd have a talk with your GC , find out how the electrician came to his conclusion and possibly find another electrician.

FWIW, I have separate services on the house and garage. The house used to have a 60 while the garage had a 200 when we bought the place.

 

[2ManyProjects]

I have a simple question. What are the reasons I might not be able to get 200 amp service to my new build detached shop?

Well, besides the obvious (read: "$$$"), I'm not sure that there are any, or what they might be in YOUR particular location & situation -- and neither does anyone else here. Frankly, until someone in a position of authority can clearly and coherently explain what those reasons are AND why they apply to your particular build, the default assumption would be that there are no such issues.

Beyond that, I have one other suggestion: Get a new electrician (and maybe a new G.C.). Here's why:

Met with electrician today with the GC and was told I could only get 125 amp service to shop with 400 amp service to house. This statement without a good answer came when I asked for an automatic transfer switch for a future generator. Also told I'd be "OK" with 125 amps even though they didn't really listen, know or understand my list of existing tools (Lincoln 180c/220, 220 compressor, 220 cyclone dust collector, future 220 table saw).

At the very least, I expect people who work for me to listen to me. If they have a good reason to disagree with something I've said, by all means bring it up. But they better be ready to defend their position rationally and with specific logical reasons, not just shoot-from-the-hip generalities.

Whether or not you "need" 200-Amp service to do what (you think) you want to do in your shop, now or in the future, is completely irrelevant. That wasn't your question. If you want it, and you're willing to pay for it, then that is what you should get, barring any legal issues.

 

[sberry]

I can say this for a fact, about 99% of these threads grossly over estimate the power required. Out of a couple dozen garages have never,,, never been called back because of an overloaded feed breaker at 60A, know a couple small weld shops that run on 100, have done it myself with way more equipment than on this list. 125 is pretty good and likely the limit of the breaker the panel they are installing it in will accept.

 

[Thumper68]

I see no reason why you shouldn't get 200 amp service to both. When I built my shop I ran a 200 amp panel in the shop, The power company just told me to run the line off the second set of lugs in the meter enclosure. When I installed my new 5hp table saw I was browning out all the feeds from that transformer, me and 2 others, so the POCO came out and installed a new transformer.

 

[theoldwizard1]

I can say this for a fact, about 99% of these threads grossly over estimate the power required. Out of a couple dozen garages have never,,, never been called back because of an overloaded feed breaker at 60A, know a couple small weld shops that run on 100, have done it myself with way more equipment than on this list. 125 is pretty good and likely the limit of the breaker the panel they are installing it in will accept.

About the only thing I can think of for a 1 man operation that might exceed 60A would be a plasma cutter and only because it requires an air compressor to be running simultaneously.

 

[Gerald O]

Middle of the winter--two electric resistance heaters are running (15kw), the car lift is being raised (4kw), the 7hp air compressor is starting up (8kw), all the lights are on (1kw), and the hot water heater for that shop bathroom (5kw) is running. 33kw = 143amps.

 

[jam0o0]

About the only thing I can think of for a 1 man operation that might exceed 60A would be a plasma cutter and only because it requires an air compressor to be running simultaneously.

this is my situation. 22 amps on the sticker for the little plasma, 24 for the air compressor. 30 amp breaker for the a/c. and 20 amps (120v) for the lights. 60 wont cut it.

 

[sberry]

Ever tried it, I bet it doesn't trip a 60. Not including 15 kw of heat.

 

[theoldwizard1]

this is my situation. 22 amps on the sticker for the little plasma, 24 for the air compressor. 30 amp breaker for the a/c. and 20 amps (120v) for the lights. 60 wont cut it.

Turn off the A/C for a few minutes.

 

[sberry]

I had a fire, set up a temp pole with 100 on it. Even the inspector mentioned,, good luck, never an issue, have a 3 hp well on top of it, air on demand, 50A welding equipment, several fridges at the time. 5 hp pressure washer

I have seen all electric house overload a 60, electric water heater, dryer, cooking. Seen a bar overheat a service on a hot summer Friday night fish fry but never a shop. My neighbor had a panel issue a while back and didn't want to change it out, found another main but tested it, said for giggles he turned on everything he could,,, 43A One of my buds a real master says all electric house about 85 peak., that's running the dryer while cooking a big meal and taking a hot shower at the same time.

 

[bluebolt]

All I can say is when I had my 30x40 shop built I had a 200 amp service put in. Shop was far away from the house pole so they put up a new pole closer to the shop on the side street (I am on a corner). As someone mentioned a 200 amp box has more CB slots, it made the wiring much easier. At an average of $20 a month for electric I doubt the electric company has even got their money back for the pole yet.

 

[sberry]

I will agree a shortage of spaces is a real common issue. Way bigger problem than actual lack of power.

 

[A_Pmech]

Regardless of what wire you run or what size panel you install, the power company is going to get the last laugh when they hang a 15kVA pole pig to heat it up.

 

[Gerald O]

...Met with electrician today with the GC and was told I could only get 125 amp service to shop with 400 amp service to house. ...

He's just telling you that because he doesn't want to do the extra work/expense to set it up for a bigger service to your shop.

I just had this put in for my new shop: Split service-150A to the house and 150A to the shop. I only had a 200A service to the house originally. So they had to change the meter base to a dual-lug 320A/400A base. That feeds two 150A main breaker/disconnect panels with one feeding a 200A sub in the house and one feeding a 200A sub in the shop.

 

[James-W]

When I had the electric company run power to my garage, they would run whatever I wanted run for free since it was less than 100 feet. But the thing is, why would I want them to run anything less than a 200 amp service? It doesn't cost me any more each month to have the larger service, so why not have it available just in case I should happen to need it?

 

[sands35]

Middle of the winter--two electric resistance heaters are running (15kw), the car lift is being raised (4kw), the 7hp air compressor is starting up (8kw), all the lights are on (1kw), and the hot water heater for that shop bathroom (5kw) is running. 33kw = 143amps.

this is my situation. 22 amps on the sticker for the little plasma, 24 for the air compressor. 30 amp breaker for the a/c. and 20 amps (120v) for the lights. 60 wont cut it.

The only way this is a problem is if they all happen to turn on at the same time. It's not the steady state that's the issue - it's the startup. Even then, you can't really rely on the name-plate ratings for the actual amp draw and inrush current (possible exception in the lights - but I'll bet they are conservative too). Really need an amp meter or o-scope to figure it out.

60 amps *might* be sketchy, 90 or 100 is perfect and 200 way overkill.

That said, I'll have a 200 amp panel because it is cheaper for me given the property layout. (might go with a 100 amps, we'll see - need to get a final quote from the power company) Shorter run from the pole to the garage then from the house.

 

[sberry]

I agree, no reason not to run 200 if you can get it for free. Yes there is inrush on occasion but you don't need to really worry about it. A shop vac is good example, on a 20A circuit, starts of 60A or more. Starts would be an issue with a genset, not much worry from line power.

 

[Blk88GT]

I ended up with a 200amp service to the house and a separate one to the shop. Do I need it? Maybe not. But I've got it and will never max it out. It cost a bit, but in the grand scheme of things wasn't a huge deal.