The Stovebolt Site Forums The Shop Area The Tool Chest Help Please! Electrical plans for my shop!

Until recently, we had the main garage compressor, paint booth compressor, original (old) garage compressor, extra tank in the old garage and an extra tank in the hydraulic shop. All interconnected.

I met with an electrician last night. Our sons played on the same sports travel team, but I had lost contact with him until recently.
He added to my education about electrical wiring and code. Coolwhip has also given good advice when we talked on the phone.

1. If I install a 200A service box, then I will need to have another meter installed. That means a $15 per month meter charge. Every month. Forever. $180/year just for the meter.

2. He said I can't put three 220V outlets all on the same 60A circuit because the inspector would fail it. Makes sense. Inspector will see this as unsafe because it has the potential for three 220V devices to draw power all at the same time, thus overloading the circuit. He likes Mike B's idea of a single 220V outlet mounted between the garage doors and use a 25' extension cord when needed. This would be a dedicated conduit for a 60A circuit for the welder.

3. He told me to run a dedicated conduit for the auto lift. The lift draws 14.5 A, so it would be a 220V with a 20A breaker.

4. The lights will be LED and on a single circuit with a wall switch so I can turn on different banks of lights depending on my needs.

5. The 110V wall outlets can be on a 20A circuit. I'll probably divide each outlet (either a duplex or double duplex) into 2 separate circuits.

6. The window A/C unit will have a separate conduit for 220V and a 20A circuit.

7. A future air compressor will have a dedicated conduit running to the back right corner. They are typically 220V and 15A. So I'd need a 20A circuit breaker.

So break it to me gently. With all that stuff, do I really need 200A service and to spend (GULP!!) $180 a year for an extra meter?

Ok, you asked for it! Two questions to be answered.

1. Are you building this as your personal “Hobby” Shop?
2. Are you planning on doing some side work for cash?

If the answer to #1 is yes, then the answer to your question is no.
If the answer to #2 is yes, then the answer to your question is yes. Consider it a business expense.

Unless you’re independently wealthy it wouldn’t make sense to spend the extra forever.🛠

One of those two adjectives has never been used to describe me.

It's a hobby shop for sure.

But it truly seems that all of my circuits will add up to more than 100A. So that's gonna be the deciding factor I guess. Right?

Your main breaker doesn't have to be the sum of all the downstream breakers. That would assume the each breaker were fully loaded all simultaneously. There's an allowance in the NEC for diversity. I recently added a new main breaker to serve my wife's new greenhouse and a 220V and additional 120V circuit for my garage. I put in a 50A main that feeds a 30A 220v breaker and two 20A 120v breakers, which would be 70A if you just added them up. Ran the install by my Electrical Engineer business partner.

hey jay , from prior talks what you have existing for a electrical service is it even big enough to get you 100 a to your shop? you have to get a load calc. done on your house! then ask yourself am I and the family done remolding room add. , extra bath, garage into man cave, micro brewery. my personal favorite. without having load calc.as a base figure who knows? then like always its time&money. hopefully your friend can do it for you.

Lugnutz, If you cannot pull what you want/need from your Home electric system. Then you'd better add the meter. Now I'm a Old Electrician from a Power Plant. I was trained in the plant. Never got Certified. But looking at your Home Service Entrance. Is it arraigned so that attaching a disconnect box to your Service outside your house. Or will the connection need to be inside the home.

if you are stuck with a separate meter personally I would go 200 a price in material and labor other than wire is very min. then you could do what you want when you want how you want . central heat & air , huge air comp. expand and grow. price for separate meter is the same here

There could be one other option.

If your house has a single panel (150a or 200a) you should be able to swap the single lug meter can for a dual lug meter can. This dual meter can allows you to connect two service panels to one common meter (one for the house and one for the garage). The thing you'll need to figure out is what the max amprage your local electric company allows to be hooked up to their dual meter can. Some allow 400a total (2) 200a panels and some only allow 350a total (1) 200 & (1) 150a panel.

Once this is fgured out and approved you would install a 200A fused raintight disconnect switch next to the meter and fuse it for your panel size 150a or 200a. The garage panel would then be feed out of this new disconnect switch. If you installed a 40 circuit panel you would have enough breaker space to make EVERYTHING in the garage have it's own didicated breaker!

You will NEVER use or need a 200a service for a backyard hobby garage. The only reason to go big is you get more breaker spaces. Remember, the only BIG items you listed are all intermittant duty things...you might be welding and the compressor kicks on for 5 minutes or the AC kicks on while you're sand blasting with the compressor running. A 100a panel would be fine for all of this as long as you don't run out of breaker space!

BREAKER SPACES NEEDED;

2 Welder 50a (stick)
2 Welder 20a (MIG)
2 Air Compressor
2 Lift
2 A/C
1 lights inside
1 lights outside
4 120v GFIC outlets (North, South, East and West walls)
1 120v GFIC outlets for garage door openers
1 120v GFIC outlet outside

Total 18 spaces used


Mike B

The power company can provide you peak demand on your current home. Based on that you can determine if a separate feed to the shop is required or can you put in a breaker such as a 100amp to your shop as a sub panel. If you have to run a separate feed to the shop do 200amp. The cost difference between 200 and 100 is not enough to go just 100amp. I did not read all the discussion but most service entrance cable is aluminum. Also it is not uncommon to use aluminum for high ampacity circuits like 50 or 60 amps. You need correct terminals and a special anti corrosion paste on the terminals. The receptacles and panel lugs will be marked AL for use with aluminum. I have three 200amp panels all connected to a single meter. They use current transformers on each panel feed and the meter totals the usage.

Jay, you have been to my shop and I have gotten by very well pulling off the house meter to the box inside my shop. Never a problem in 12 years and I've had the compressor, welder and all lights going at the same time. No problem. You may want to discuss this with your electrician or the code inspector......they different from town to town, county to country depending on who you talk to as I found out on the last two houses I built this year each in a different city/county.

.....as always, I know you will measure twice and cut once. Hope to get down your way soon.

Mike is right, it's not the amps it's the breaker spaces. For that perpetual cost, I would figure out a smart way to get by without it, but have some expansion options on breaker spaces. That's my problem, anything I add, I'lI have to add a subpanel and I'm using those thin breakers for light/plug circuits. have a 50' long extension cord for my MIG welder as sometimes it's easier to take the welder to the project than the project to the welder. It works fine for me.

hey jay wondering how you are making out ?

Thanks for asking. The good news is I think I have found the right electrician for the job. He actually came over on New Year’s day, and really showed interest in doing all parts of the job. Several days prior, I had an electrician come by who was only willing to do part of the job.

This Thursday, they plan to dig the trench for the underground conduit. I will have a disconnect box installed next to my meter can and then run power through the conduit to the shop. We have also worked out where the outlets will go in the shop.

I’m trying not to be impatient. I don’t want to make this guy lose interest because of my impatience. He’s busy with other projects, but that’s a good sign that he works a lot because he knows what he’s doing. I hope to see his estimate soon.