Sub Panel in detached garage.

[38 tow]

I am sure the answer to this question has been answered but for the life of me I have been searching and cannot find a simple answer.

Here is the background. I just built a 40'x40' shop about 200' feet from the house. Power company won't let me have two meters so I will need to pull wire from my main panel on the house.

The main on the house is a 200 amp service. I would like 200 amp service in the shop also.

First question: Am I crazy? every electrician I have had here at the house to bid for this job says that 200 amp in a shop is unheard of, and that 100 amp will be more then enough.

Second question: If I am not crazy, then do I really need to upgrade my service to a 400 amp main on the house? (that is what I am being told).

The shop will not see a lot of use it is a hobby place someplace for me to restore cars, and do wood working. I want to run a huge air compressor and eventually a lift, other then that my welder is about the biggest draw of power. My biggest problem is I don't want to get down the road and wish I would have gone bigger but I don't want to waste money if it isn't needed.

Some direction would be awesome. (even if you all are better at searching then I am and can point me to another post)

Thanks

 

[vekster]

100a would be more than enough for a hobby shop.
Keep the 200a at the house and feed 100a to the shop


Sent from my iPhone using Tapatalk

 

[theoldwizard1]

First question: Am I crazy? every electrician I have had here at the house to bid for this job says that 200 amp in a shop is unheard of, ...

It is uncommon !

Second question: If I am not crazy, then do I really need to upgrade my service to a 400 amp main on the house? (that is what I am being told).

True

The shop will not see a lot of use it is a hobby place someplace for me to restore cars, and do wood working. I want to run a huge air compressor and eventually a lift, other then that my welder is about the biggest draw of power. My biggest problem is I don't want to get down the road and wish I would have gone bigger but I don't want to waste money if it isn't needed.

With the small amount of actual information that you have give us (where is your location ?) the best anyone can do is a wild *** guess. 90A should be adequate (yes, 90A not 100A; it has to do with wire size). If you haven't bought your compressor yet, try to keep it to 5 HP.

If you are careful, a typical one man shop can run on 60A if you don't run more than one of those large tools at a time.

 

[checkthisout]

I am sure the answer to this question has been answered but for the life of me I have been searching and cannot find a simple answer.

Here is the background. I just built a 40'x40' shop about 200' feet from the house. Power company won't let me have two meters so I will need to pull wire from my main panel on the house.

The main on the house is a 200 amp service. I would like 200 amp service in the shop also.

First question: Am I crazy? every electrician I have had here at the house to bid for this job says that 200 amp in a shop is unheard of, and that 100 amp will be more then enough.

Second question: If I am not crazy, then do I really need to upgrade my service to a 400 amp main on the house? (that is what I am being told).

The shop will not see a lot of use it is a hobby place someplace for me to restore cars, and do wood working. I want to run a huge air compressor and eventually a lift, other then that my welder is about the biggest draw of power. My biggest problem is I don't want to get down the road and wish I would have gone bigger but I don't want to waste money if it isn't needed.

Some direction would be awesome. (even if you all are better at searching then I am and can point me to another post)

Thanks

200 Amp is overkill....wayyyyy overkill.

Convert it to watts: 200 X 240 = 48,000 Watts or 64 Horsepower.

What exactly will you be doing that will draw this much energy???

Electrical resistance heating for a building the size of yours draws a huge amount of power, like 20K watts so in that case 200 AMPS would be somewhat justified but houses with 200 AMPS have electric heat, electric range, electric hot water, electric clothes dryer and a number of 20 AMP circuits and this 200 AMPS is able to keep up with all that on full bore all at once........

 

[38 tow]

Thank you for your quick reply's I am glad i asked the question.
For those who want more information I live in Utah. I am looking at putting my house and shop all on solar. The company that will install the panels is one of the contractors that we had here to bid the job.
I was pretty insistent on wanting 200 amp service to the Garage but listening to all your input has been helpful.
I think I will rethink my actual demands as far as power goes and then make a more informed decision.
Please any and all feedback before I pull the trigger and hire someone is more the welcome. (although after reading so far I might be switching to a 100 amp sub panel)

Thanks again.

 

[gpflepsen]

Another thought. You may be able to run two feeds from your meter, one to the house panel and one to the shop panel. This would not be a sub-panel but just another panel. You would have to ensure your service to the meter is adequate for the combination.

My house has a 200A panel and a 150A panel both fed directly from the meter. The shop sub-panel is 90A (wire size accommodation) and ran off the 200A panel.

 

[gpflepsen]

Here's what I was talking about in the meter base. This isn't mine... Blue is fine in Canada...

Image from http://www.garagejournal.com/forum/showthread.php?t=113720&showall=1

 

[38 tow]

thanks for your replies. I have decided to run just 100 Amp out to the shop that way I don't need to change out my meter base and upgrade my panel. Thank you all for your help in making this decision.

 

[Notgrownup]

I have a sub in my shop I run 4 wire mobile home feeder in conduit. 100 amp breaker in my main panel feeds it. I plan on putting everything I need and not be underpowered....

 

[wyliesdiesels]

Will u have AC, electric heat or any other large electric loads?

100a would most likely be more than enough for u. 200a for what your doing IS crazy...

At 200', youre gonna need minimum #2 cu or 1/0 AL. The AL wire will be way cheaper than CU. A perfect wire for this would be 2/0 AL MHF....

.....

Second question: If I am not crazy, then do I really need to upgrade my service to a 400 amp main on the house? (that is what I am being told).....

True

Not automatically true.

Having two 200a panels doesnt automatically trigger the need for a 400a service. It all depends on the loads.

In order to determine if 400a service is necessary, u need to do load calcs. And without those, most PoCos wont upgrade your service.

Here's what I was talking about in the meter base. This isn't mine... Blue is fine in Canada...

Image from http://www.garagejournal.com/forum/showthread.php?t=113720&showall=1

Interesting that u guys have blue and bare neutrals up there.

I have a sub in my shop I run 4 wire mobile home feeder in conduit. 100 amp breaker in my main panel feeds it. I plan on putting everything I need and not be underpowered....

What size MHF? If #2, the ampacity is 90a NOT 100a and the breaker should be changed...

 

[Notgrownup]

What are the odds I am going to use that kind of juice ....I got the wire my electrician told me to and the breKer size he said I could use...

 

[wyliesdiesels]

Theres a lot of confusion about the proper rating of #2 AL.

U obviously can do what u want but it isnt right...

 

[OccupantRJ]

I am a big time shop hobby person. 45 years worth. I have had a shop with 200 amps and now have a shop with 60 amps. I will be upgrading to 100 amps. It will be perfect for a one man shop unless you have some mighty strong amp draw going on.

 

[Notgrownup]

Theres a lot of confusion about the proper rating of #2 AL.

U obviously can do what u want but it isnt right...

I will check my wire. It may not be MHF .... The local supply house gad it ready for me... It's what the electrician called it....
I just bought it....I sell medical supplies, not electrical.

 

[wyliesdiesels]

I will check my wire. It may not be MHF .... The local supply house gad it ready for me... It's what the electrician called it....
I just bought it....I sell medical supplies, not electrical.

The key here is the gauge of wire not the type. MHF is fine @ 100a in the right gauge.

 

[justsam]

First I agree with the 100 Amp, as I have pretty much your same size shop with similar present and future loads, and have never tripped the breaker.

Since there is a common power source for shop and garage, you should look at them combined. If your house is electric heat, electric range, electric dryer, A/C, electric hot water heater, electric vehicle charge, etc. you could have issues with the 200Amp total, if you fully load the garage as well.

 

[Notgrownup]

The key here is the gauge of wire not the type. MHF is fine @ 100a in the right gauge.

OK... I woun't argue over something I know very little about... I know it's 4 big *** wires..LOL Is that a gauge... BIG *** GAUGE... lol...
I can talk to you about wound care products, pressure prevention products, Needles and syringes, Incontinence products but Electricity scares me... I just met with an Electrician this morning to wire my new sunroom...

 

[darkk]

I have a 200 amp panel in my attached garage addition. We ran wire underground to the garage and under the garage floor with 100 amp to the main house. Sometimes it seems like I need more power. Lights constantly dimming in the house or garage when something with heavy power is turned on/off...

 

[wyliesdiesels]

I have a 200 amp panel in my attached garage addition. We ran wire underground to the garage and under the garage floor with 100 amp to the main house. Sometimes it seems like I need more power. Lights constantly dimming in the house or garage when something with heavy power is turned on/off...

Thats the result of voltage drop and could be many things but not the 100a capacity in the garage since lights are dimming in the house also.

What size wire did u use and how long is the run?

What size transformer if u can read it? Could be undersized...could be bad connection....

 

[brian1210]

First off, I had a mobile home on my property when I bought it, then built a stick built home on my property. Local power company said I had to upgrade the transformer for a cost of $5000 plus cost of wire to power meter. That was going from a 100 amp feed to 200amp feed. There are some questions that need to be asked. You should call up your power company and tell then what you would like to do. Might be cheaper for power company to run a wire to the garage with a second meter. You might decide the cost to run 200 amps to the garage may not be worth it. Plus where is you breaker panel in your home? Grated codes are different from area to area but if they make you install a small panel to install a 200 amp breaker to feed out to the garage. Do you want to cut drywall to install it?
If you panel location is like mine and a wife like mine. You could kiss that idea good bye.

I agree 200 amp is over kill unless 3 or 4 people are working in the garage at the same time.
My brother has a two car garage and works on cars by himself, he uses 60 amps and no issues.
I have a 24x36 by 10 foot tall. I installed 100 amps. I was told that is over kill but I never know what the future holds. Not sure who might be working in the garage with me.
It is easier and cheaper in the long run, to do over kill now.

 

[jvitez]

The proper way to answer your question is......mathematics!








Think about everything you want in the shop that uses electricity, and anything you might reasonably want in the future. Now, what might be on and running at the same time? Eg.: lights, compressor, welder, heater, electric blast furnace, grow op lights, etc. If you plan on AC you won't have both a heater and AC on at the same time. Now add up the wattage, not amperage, of everything you could have running at the same time, divide by 240 and that is the minimum amperage you need to deliver to your shop.

Once you have this number, do a proper NEC load calc on your house. Add your shop's load your home load. This is how you'll know if you have enough ampacity to your property to service the combined load.

Eg:

2000 watts of fluorescent lighting
5500 watts for big a$$ compressor
2500 watts for a lift
400 watts outdoor lighting
250 watts stereo
1000 watts receptacles (battery chargers, trouble light, beer fridge)
300 watts NG unit heater fan/blower use
___________________________

11,950 watts

11,850 watts/240 volts = 49.8 amps.


This shows that a 60 amp subpanel really is plenty for most guys shops, unless as others have mentioned there'll be more than one guy working at the same time.