Is 100A enough for a 60x40?

[learfxr]

I am calling around getting quotes for my shop build to see what everything will cost and was talking with an electrician today. He said he should be able to tap off of the house and run 100A to the shop, if I needed more I should get a seperate service. I'd rather not do a seperate service if I can keep from it.

I'm building a 60x40 steel shop with 3 12' wide doors. Kind of like having 3 car service bays. I plan to install a 2 post lift in one bay later. I have a Miller 220V Mig and Plasma. So that's the only large items I know I'll run so far. It's just a hobby shop so the power useage won't be crazy.

Any tips?

 

[vwgtivw]

I am no electrician, but you'll need more than 100 amps.

 

[walrus]

I am calling around getting quotes for my shop build to see what everything will cost and was talking with an electrician today. He said he should be able to tap off of the house and run 100A to the shop, if I needed more I should get a seperate service. I'd rather not do a seperate service if I can keep from it.

I'm building a 60x40 steel shop with 3 12' wide doors. Kind of like having 3 car service bays. I plan to install a 2 post lift in one bay later. I have a Miller 220V Mig and Plasma. So that's the only large items I know I'll run so far. It's just a hobby shop so the power useage won't be crazy.

Any tips?

You need to do a load calculation if their is any question. How many people working in the shop at one time? If its just you I doubt you need more than 100 amps

 

[learfxr]

I have no idea what the loads would be.

I want to run lots of lights inside. I will run a mig and plasma once in a long while. Nothing too special

 

[walrus]

I have no idea what the loads would be.

I want to run lots of lights inside. I will run a mig and plasma once in a long while. Nothing too special

You can run a lot of T8 fluorescents on 20 amps. I have 3 rows, each 32 feet long 4-4ft tubes per fixture and I don't believe its more than 12 amps.

 

[Aceman]

I have no idea what the loads would be.

And then you ask us if 100 amps is enough????

Why don't you put in a 100 amp panel, if you trip the main or start dimming the lights in the house, you'll know you should of went larger.

What you are asking us here, you should be going over with your electrician....

 

[Charles (in GA)]

Really need to figure out what you MIGHT want to run in the future and what might have to run at the same time. Example, a 7.5 hp compressor, about 35 amps, and if you plan on plasma cutting you need to be able to run the compressor and plasma at the same time. Lets say you are doing that after dark, lights, well, for me, thats a potential of 48 amps for the MH fixtures plus fluorescent over the workbench and a couple of halogen work lights. Yes, I could easily overload a 100 amps.

Get some figures together on various equipment, its all available on the web, manuals on plasma cutters, welders, etc.

Charles

 

[kbs2244]

Square footage has nothing to do with electrical needs.

I have seen one machine that fit into a 4x8 foot space that drew over 400 amps.
And I have seen warehouses that only need 100 amps for over an acre of floor.

You need to do some calculations.

 

[Goobzilla]

I put a 125 amp subpanel in my 40x64x12. The price diff from 100A was negligible according to my electrician, but you should be fine at 100A. Plenty of room for current and future needs (I think). I have 4 220V outlets (2 welding/plasma cutter, 1 for compressor, 1 in overhead for future 2 post lift), and a **** ton of 110's, I also used the large CFL's in my shop which use less than 1 amp each.

 

[sberry]

Don't lose sleep, 100A will be plenty, in most cases 60 would. About 95% of the time I feed garages with a 60A breaker, never had one call to say they tripped a main. My bud has mechanic shop fed from his house, 25 years, never tripped once.

 

[sberry]

Most people over estimate the amount of power they draw. I had to use a 100A as a temp one time, 3 hp well, 3 hp air comp, 5 hp pressure washer, various welding, 20 people living on it, all gas major appliances though, 4 fridges, back in the day when cfl's were a *********, dozens of light bulbs, some 500 watt lamps, microwaves, toasters, etc, never tripped, not once.
My neighbor recently had a breaker problem, tried to turn on everything he could imagine including heat pump, maxed out near 50A. Loads found in small shops especially DIY types are so intermittent they rarely add up to much without specialized equipment like a pottery kiln. Most don't really add much to demand factors unless there is large AC units.

 

[bucs012]

I went through this last Fall when building my new 50x30 garage. House is wired at 100 amps.

Ended up going 200 amps on the garage. Why? Because I may want to run a large compressor some day. I might want to weld in the future and run A/C. All at the same time. I already heat it during the winter, run 19 lights and my compressor, radio, lights etc. Each electrical heater has to be on a 30 amp circuit. I wanted to make sure I didn't kick my self in the but a few years from now for not spending an additional $1,500 or so.

It really was not that much more to wire it at 200 amps. Just more planning up front. The power company came out and ran a line from the meter on my garage over to the box in my yard to bring in 200 amps. That was all free by them. The cost was for the trencher and wiring. In the end I probably spent $1,500 for someone to do all the work for me.

Resale might help as well. If someone is looking at buying the place down the road and you don't have enough power out there, it can blow the deal too.

 

[sberry]

Electric heat would be a consideration. But a hoist isn't much of a deal, 45 seconds @ 15A on occasion. How insignificant it is, mine is listed 13.9/13 fla and they allow a 14 wire.

 

[Gary S]

I'm happy with 100A in my garage and I have 40A of that being used for electric heat in the winter. There is still enough available power for my compressor, welder, lighting, and other tools with the heat on.

 

[NUTTSGT]

100 amp should be plenty. Let me ask you this, you do have atleast a 200 amp service in the house don't you ?

 

[hook982]

And then you ask us if 100 amps is enough????

Why don't you put in a 100 amp panel, if you trip the main or start dimming the lights in the house, you'll know you should of went larger.

What you are asking us here, you should be going over with your electrician....

Gosh, I wish I was as smart as you, you are just too cool....

 

[Aberdale]

It all comes down to how many electrical gizmos you want to run at the same time.
I have a 40x60 shop. In it, I have 2400 watts of lighting, a 2 stage air compressor, two welders, a 2 post lift, a 3 phase converter running a 3 phase lathe and mill, 2 drill presses, numerous grinders, sanders, saws, etc., and a 3 ft. exhaust fan. This all runs off a 100A service panel. Although the lights and air compressor are always on, I rarely run more than one electrical tool at a time, (i.e.; I don't run the welder and mill, or the mill and lathe at the same time) and have never had a load issue yet.

The first step is to add up the amperage of all of the electrical items that you plan on running in the shop, then add up all the separate circuits that you want to run them to determine the number of circuits that you need. This will tell you how many breakers you will need, and hence the physical size of the box. Then, you need to decide how many of these circuits you will be likely be running at the same time. (It would be a good idea to add a safety factor, or plan on future uses when estimating this.) That will determine the minimum amperage box and supply wiring size to install.

Dale

 

[Norcal]

100 amperes is fine, just use the largest panel you can find, (40-42 circuit) and if one has a proper 100A circuit breaker ahead of it, a 200A main breaker panel will be fine, since it is only a disconnect.

 

[sberry]

Do we see 40 space panels with 100A factory installed mains?

 

[Norcal]

Do we see 40 space panels with 100A factory installed mains?

Most have seen is 30, which why the 200A was brought up, a 100 A may be backfed w/ the required retainer clip on a plug in breaker.

 

[matt60j]

I put in a 100amp panel in my shop. Should be plenty. I have (15) 4 bulb t-8 fixtures so thats about 15 amps. 220 welder hook up. Branched off that for the future lift. 30 amp slot for future air comp. Plenty of space left. -MATT

 

[sberry]

You could crowd a 20 but 30 spaces is a lot for this type of garage. I have a building with 20 and its full but I have a LOT of recept and light circuits, way beyond what is needed mostly for service and change convenience. I really could have ran it in 6 or 8 and comfortably in 10 but I had long runs in pipe and wanted to pull in one shot, have several with one duplex to the breaker, don't use a third of it. I had anticipated a possibility of several 500 quartz being used down the road but it was substantial overkill. Didn't share any lights and recepts on circuits.

 

[skidmark63]

I agree. 100 amps should work. Thats what I ran my shop with for years with a plasma, welder and smallish compressor and all the usual smaller tools. My problem came up when I got a Chapion 2-stage comp. w/ a 7.5 hp Baldor motor. When it turned on the lights in the house went out! The problem wasn't the 100 amp panel being fed from the house, it was an under sized service from the elec co. They lowballed the transformer because they can usually get away with it on a house, but when you like to play with cars its not enough. They installed a 10kv tranformer which translates to approx. 90 amps of total power. They put in a 25kv unit and the problem mostly went away.

 

[hidollartoys]

You might want to consider multiple 400 amp panels in the shop. This should meet ANY "future" requirements. Especially if you want to run a foundry. You could also look into 3 phase power "just in case" you want to build aircraft or do production baking.

 

[mmurphy]

I do not think you will come close to overloading 100 amp service panel, unless I missed that you are running a shop where you have several people working for you. I have a 2 post lift,welder, air compressor, several lights, and never had an issue with 50 amp breaker that I am running from my house.

 

[juiced10]

I do not think you will come close to overloading 100 amp service panel, unless I missed that you are running a shop where you have several people working for you. I have a 2 post lift,welder, air compressor, several lights, and never had an issue with 50 amp breaker that I am running from my house.

X2 same set up in my pole barn.no issues

 

[Jeff Ivers]

I didn't read all the posts in reply to the OP, but a few things I did not see are as follows. I have a 1200 sq ft shop with lots of flour. lights, 110 v Mig welder, 2 220v baseboard heaters, 6 hp compressor, etc. I use a 100 amp breaker box and do not have any problems. In addition, I run a 30 amp feed from this shop to my barn. Locally, the electric company wanted my shop fed from the house which has a 200 amp box and a 100 amp breaker for the feed to the shop. Add the watts of the items you think you will have on at the same time and divide by 110 to determine how many amps you will need. The critical thing in your plannig is the wire feeding the shop. It must handle the amps of the installed breaker box, assuming the full load is being drawn. You are not likely to be able to upgrade from a 100 amp to a 200 amp box without changing this feed line (this can be quite expensive). The second critical thing is to anticipate how many circuits you need. If I were wiring mine from scratch, I would plan more circuits. As an example, I have plugged in a supplemental eletric heater that draws 15 amps, and tried to plug in a work light with 2 500 watt halogen bulbs (10 amps) to the same 20 amp circuit and blown the breaker. To be on the safe side, have at least two separate outlet circuits on each wall of the shop. Finally, you can use 1/2 thickness breakers to increase the number of circuits in the box.

 

[learfxr]

Thanks for the advice guys. I've been really busy moving into the new house and have many projects going at the same time. Building fence and other fun stuff. I had an electrician come out and put me a 220 outlet in the garage so I can run my mig and plasma since there is no shop yet.

I'm not 100% sure what I'll do for the shop, or when it will get built. I have a new 12x16 wood shed we just had delivered in the back yard and I want to run power to that for a light and outlet. I've talked with the electrician a little about trenching power to the shed. I think he said he would run a 30A service to the shed for lighting and outlets. I basically want to have a couple of inside lights and outlets for the batt charger for the riding mower. We discussed trenching a large conduit that could go from the house to the shed, and then run to the back of the property for the future shop.

I have lots of research and planning.

Thanks

 

[learfxr]

Here is a pic of the panel from the 30x40 shop that I was renting for about 5 years. I think it was 125 or 150 main breaker. It was running a water well, only a couple of lights, my mig and plasma-one at a time. I never had issues with power, cause I don't use much for my stuff.

My new shop would have much more lights than the shop I was renting. Some day I'll upgrade from a 110V air compressor to a 220V compressor. If I understand the math, the 220V would draw less current with the higher voltage, right?

Box in the old rental shop