Building a garage workshop: some questions

[curiousdork]

Hey guys,

Today I'm meeting with my general contractor for a bid to talk about rebuilding my one stall garage into a larger'ish 1 stall garage with room for a workshop.  My house currently sits on a 100 amp service - pittance, yes - and one of the things I want is to upgrade my electrical service.  I'm rebuilding my kitchen *after* the garage (mostly cabinets and tile work, maybe running a little bit of electrical) as I love to cook.  What size service do I need?  I wasn't sure if 200 amps is plenty, I know it is for the average home but I want my shop to be slightly more flexible and thought maybe a 325 amp service (200 amp for the house, 125 amp subpanel to the garage) would suffice?  But 325 amp seems like overkill to me.

Ideally, I would love to be able to woodwork in my garage year round regardless of weather (since walking to my garage is 1000x more fuel efficient than driving 20 minutes to the shop I'm renting).  So obvioulsy I'll need heating/cooling.  Ideally, I want to be able to run a small dust collector + tool.  Since I own a Festool CT MINI, my goal is to be able to have two different Festool dust extractors I can move around in addition to, say, a portable Oneida Dust Gorilla portable.  I don't intend on running all the tools simultaneously since much of it will be on casters as I plan on being as portable and small as I can.

Any thoughts on electrical service?  Please share, I'd love to tap into the forum's wisdom!

 

[RustE]

The sub-panel in the workshop is a good idea.  That way you can cut power when changing machinery.

Ask the contractor to bid out the electric service at a few different ratings.  My initial thought is 150A minimum for the house and 100A minimum for the workshop.  While that's 250A, going to 400A might not cost that much more.

 

[IndyWoodworker]

Hello,

I have actually had my garage/ woodworking shop wired for heavy shop equipment.  Specifically a Delta Table Saw (5 HP), Vacuum System (1.5 HP), Lathe (3 HP) and radiant heater. I was able to do this with a dedicated  80 amp service using a combination of 110V and 230V service.  This was coming directly from the 200 amp service into my house.  The 230V service was for my table saw, vacuum system, and lathe.  In the first and last instance, these pieces of equipment ran on 230V and I rewired my Delta vacuum system to also run on 230V.  The best thing I found was to calculate how much amperage you might need at peak load (usually startup) and then size accordingly.  My electrical contractor and local woodworking store suggested that I start my heavy equipment separately.  An example would be that I start the vacuum system first, letting it get to speed and then start the table saw.  Using this approach, I never had issues with overloading the service. 

I have put together 3 shops using this method with a traditional home 200 amp service and never had a problem.  My electrician understands my request and just asks me for outlet placement.  I do have a separate breaker box for the shop so that I can isolate it from the house and not impact other circuits. 

Best of luck on your project

 

[curiousdork]

Thanks [member=63201]RustE[/member] and [member=11847]IndyWoodworker[/member] for your replies.  I'll definitely ask about different bids on various size services.  Suppose I go up to 250 amps does my monthly electric bill go up because I have a larger service or is that still dependent on the number of things sucking up power? 

 

[RustE]

My guess is a one time fee for the size of the service and the recurring monthly fees based upon usage.  This varies widely by geographic location and utility service agreements.

 

[Peter_C]

The better question is what size wires are running to your house? This is the deciding factor for how large of a service panel you can have. Do the wires come from a pole or underground? The power company should be able to tell you what is allowed.

Unless you have a hot tub, electric hot water heater, electric dryer, etc., I doubt you need more than a 200amp service, but a quick survey of your needs should tell all.

 

[Tracky]

I have a 60A sub-panel in my garage. I find that is enough for my needs (including welding and some metal fabrication). I don't think you need more then 200A service unless you have a monster pool and a lot of AC's.

Just a thought since you are running wires: maybe you want to have enough power and possible a conduit for a future electric car. Now it is easy to rough it in. Either charging inside or on the outside wall of your shop.

If you want to charge a car and have some larger machinery running at the same time you would need at least 100A, I think.

 

[bkharman]

Go as large as you can afford. When I built my house, we got 600 a service with three panels. I have yet to see a light dim when the geo cubes kick in. Retrofitting will have different requirements, but get what you can afford after speaking to an electrician and letting him know your needs/thoughts.

Cheers. Bryan.

Sent from my iPhone using Tapatalk

 

[rmwarren]

We have 200A into the house, with a 100A subpanel run off that for the second floor, including (2) 4-ton HVAC units. Heat, oven & hot water in the house are gas-fired forced-air. Like [member=63238]Tracky[/member] we powered up the shop with a 60A subpanel off the main panel.

Heat in the shop is a very efficient radiant panel, and lighting is from LED panels. I have a 230V circuit that doubles for the heat and a single outlet for the future TIG welder, a 15A circuit for the lights and (2) 20A circuits for tools/extractor. Have never had a problem, but in particular I don't run a large compressor. That is the only thing I can envision causing an overload, with the heat most likely. If I end up using the welder while in heating season I would probably just switch off the heat for a short time.

In particular I would recommend the heat & light fixtures, they are recent additions and I love them.

Have fun with the new shop, and welcome to the FOG.

RMW

 

[Peter_C]

~Like [member=63238]Tracky[/member] we powered up the shop with a 60A subpanel off the main panel.~

~I have a 230V circuit that doubles for the heat and a single outlet for the future TIG welder~

FWIW My Lincoln 175 TIG requires a 100amp breaker, and hard wiring. I used to run it on a 50amp breaker, before upgrading my own panel from 100amp to 200amp, but I couldn't hit the "Go Pedal" far or it would blow the 50amp breaker. What I am saying is buy a welder that matches your electrical panel. Depending on what you are doing a Mig welder with a spool gun is easier to learn with.

 

[rmwarren]

Woof! I've owned MIG welders in the past, and never needed over 50A for an old Millermatic 175 that I used in 3-4 different buildings. I could easily handle 1/4" steel in one pass with .030. Something does not sound right.

I am set on TIG, I enjoyed the ease of MIG when I was building utility trailers and similar stuff but want to up my game to more exotic and decorative stuff. TIG is a new skill I plan to acquire.

The machine I have my eye on is the Lincoln AC/DC square wave, 115/230V. Specs call for 22A on 230V @ 25%. I will check with the dealer before making the purchase.

Thanks,

RMW

~Like [member=63238]Tracky[/member] we powered up the shop with a 60A subpanel off the main panel.~

~I have a 230V circuit that doubles for the heat and a single outlet for the future TIG welder~

FWIW My Lincoln 175 TIG requires a 100amp breaker, and hard wiring. I used to run it on a 50amp breaker, before upgrading my own panel from 100amp to 200amp, but I couldn't hit the "Go Pedal" far or it would blow the 50amp breaker. What I am saying is buy a welder that matches your electrical panel. Depending on what you are doing a Mig welder with a spool gun is easier to learn with.

 

[Peter_C]

I am set on TIG, I enjoyed the ease of MIG when I was building utility trailers and similar stuff but want to up my game to more exotic and decorative stuff. TIG is a new skill I plan to acquire.

I fully understand as I couldn't do without both a MIG and a TIG. Aluminum spool gun works good for some stuff on a MIG, but I have done a lot of stainless welding for boats. Most of my welding is steel though so having a MIG is better for me.

The machine I have my eye on is the Lincoln AC/DC square wave, 115/230V. Specs call for 22A on 230V @ 25%. I will check with the dealer before making the purchase.

Thanks,

RMW

Took a quick look at the specs. It is lightweight which should be nice. The downfall I saw was that it is only rated to 3/16" aluminum. If that is within your limits great. Might want to read reviews on it and make sure it is the one for you. Maybe the local store lets you try it and return it if you are not happy?

 

[rmwarren]

Thanks for the input [member=62526]Peter C[/member] - I am planning to buy from a local dealer (probably South Jersey Welding Supply) so I will avail myself to their expertise. I don't have any practical experience with TIG so any advise & counsel is welcomed.

The 200A AC/DC Lincoln/Miller/Hobart class units will all be a bit of a compromise but @ the price point I think I can live with it. These days I will probably be welding < .250 and most likely 90% will be 10ga/.125". My heavy construction days (utility trailers, hitches, etc.) are mostly behind me, so I can't justify a Destiny-class machine.

Would like options for pulse and fingertip control.

RMW   

I am set on TIG, I enjoyed the ease of MIG when I was building utility trailers and similar stuff but want to up my game to more exotic and decorative stuff. TIG is a new skill I plan to acquire.

I fully understand as I couldn't do without both a MIG and a TIG. Aluminum spool gun works good for some stuff on a MIG, but I have done a lot of stainless welding for boats. Most of my welding is steel though so having a MIG is better for me.

The machine I have my eye on is the Lincoln AC/DC square wave, 115/230V. Specs call for 22A on 230V @ 25%. I will check with the dealer before making the purchase.

Thanks,

RMW

Took a quick look at the specs. It is lightweight which should be nice. The downfall I saw was that it is only rated to 3/16" aluminum. If that is within your limits great. Might want to read reviews on it and make sure it is the one for you. Maybe the local store lets you try it and return it if you are not happy?

 

[curiousdork]

We have 200A into the house, with a 100A subpanel run off that for the second floor, including (2) 4-ton HVAC units. Heat, oven & hot water in the house are gas-fired forced-air. Like [member=63238]Tracky[/member] we powered up the shop with a 60A subpanel off the main panel.

Heat in the shop is a very efficient radiant panel, and lighting is from LED panels. I have a 230V circuit that doubles for the heat and a single outlet for the future TIG welder, a 15A circuit for the lights and (2) 20A circuits for tools/extractor. Have never had a problem, but in particular I don't run a large compressor. That is the only thing I can envision causing an overload, with the heat most likely. If I end up using the welder while in heating season I would probably just switch off the heat for a short time.

In particular I would recommend the heat & light fixtures, they are recent additions and I love them.

Have fun with the new shop, and welcome to the FOG.

RMW

I spoke with my contractor and thinks that 250 amp service is plenty: 150 amps to the house, 100 amps to the shop.  I think there's a gas line that runs from the house to the garage so my neighbor says (he's been in my area for over 30 years).  If my neighbor's telling the truth then I found my heating source.  In the summer I'll just use a standard window unit since my garage won't exceed 30' x 24'.  My tools will be mobile and since I'm still a hobbyist anything larger is just a waste of my yard space.  That being said, he has an electrician in mind so I'll be consulting him as well.

Thanks for the welcome, I will say that I never thought that owning a Festool anything would mean access to FOG.  I felt like I just joined an elite group of people who own a super special tool. 

 

[curiousdork]

Go as large as you can afford. When I built my house, we got 600 a service with three panels. I have yet to see a light dim when the geo cubes kick in. Retrofitting will have different requirements, but get what you can afford after speaking to an electrician and letting him know your needs/thoughts.

Cheers. Bryan.

Sent from my iPhone using Tapatalk

That might be hard as I have other priorities.   600 amps seems like overkill.  I'm a software engineer and I live by the adage that over-engineering is easy.  As much as I would love to throw money into a problem, I'd rather size it well for the lot and size of the shop.  I'm not trying to run a full production shop, I'm a hobby woodworker who wants to craft things for friends and family (and the occassional client).  I'm also a hand tool guy and I only plan on having a few key power tools in my shop (planer, table saw, band saw, miter saw, track saw, and domino).  Maybe when I move up and out I'll rebuild a shop and get a 600 amp service but for now, this should suffice (plus my budget isn't infinite).

 

[Rick Christopherson]

200-amp total service should do you just fine, given your descriptions. Your home would have the 200-amp main, and you could get by with either 60 or 100 amp subpanel in the shop, especially if you have gas heat. (The subpanel is fed from the main.)

Don't be confused between how many circuits you have versus what their actual draw will be. A single-stall garage is not going to draw much power. The exceptions would be electric heat or welder as mentioned above. You don't run everything all at once. So for calculating load, you add up what you would use simultaneously. You'll probably find for that size shop, you'd never actually even use the full 60 amps. I have a well equipped 1800 sq ft shop, and it won't draw more than 60.

 

[JELL]

Two items that are as important as the panel rating are voltage drop and number of breaker positions or circuits you can run.  A 60 amp panel will typically have a smaller conductor feeding it then will a 100 amp or 150 amp.  This can result in voltage drop issues depending on how far you are from the main panel.  Also consider how many circuits you may need.  Lighting should be on its own circuit so if you trip a outlet breaker you don't trip the lights.  If you plan to have a Kapex with a CT attached it may be a good idea to have a dedicated circuit for it.  Add a circuit for out door lights and outlets along with 2 or 3 circuits for inside and you are up to 4 or 5 positions used.  Then down the road you want a new table saw.  A 3 hp or up will need a 240 feed.  Two more positions used.  Then maybe a cyclone dust collector.  Again 240 vote and two more positions used.  Now you at least a 10 position panel.  I would also consider locations of outlets so you do not need to run cords or have them in areas you will be walking though.  A little pre planning can set you up for expansion and improved safety at very little cost now versus changes latter.  I hope this was helpful.