Yet another Electrical question/request for advice

[John McBride]

The new shop is coming along nicely. Basically it is a brick, one car garage about 12 feet wide by 24 feet long, 10 feet from the house, and maybe 20 feet from the houses service panel.

The service panel on the house is 100 amp service. The garage has no service yet. I am looking at putting a sub panel in the garage to handle the shop requirements, which are as follows....

1) 110/220 table saw

2) 110/220 Inca Jointer planer.

3) 6 new outlets evenly spaced around the perimeter of the shop for various smaller tools.

4) Power for shop lighting, say 4 8' floresents?

So I know that a subpanel is needed. My question is, If I am pulling power from the house, how do I configure the set up?

Is the 100 amp service at the house, enough to also power the shop requirements? (two 220 vac circuts, shop lighting, and multiple shop outlets?)

I will go into the code issues and permitting etc, once I get an electrition out to give bids. But what I am trying to do here with this post, is to get a feel for what I might be up against.

Is a 100 amp service panel, that does have space left in it, enough to power the shop safely?

If so, what does that configuration look like in your estimation? Again, I am going to have an electrition come out and bid this out, and do the work. Just looking at what needs to happen to get power to the shop.

[Ken Fitzgerald]

John,

IMO 100 amp service is not enough for today's house and certainly not big enough for a shop and house IMO. I had that arrangement in my home in a Chicago suburb with a basement shop. Running the tablesaw in the basement actually pulled down the size of the television picture in the upstairs living room.

Check with your local utility company. When I built my shop here in Idaho a few years ago, the utility company added a separate power run to my shop. The shop is on it's own meter and has it's own 200 amp service panel. The utility company didn't charge for running power to the shop. I get one bill with 2 different meter readings.

My cost was the service entry, meter base, service panel and wiring. I bought the materials locally and wired the shop myself with everything inspected for code compliance.

[John McBride]

John,

IMO 100 amp service is not enough for today's house and certainly not big enough for a shop and house IMO. I had that arrangement in my home in a Chicago suburb with a basement shop. Running the tablesaw in the basement actually pulled down the size of the television picture in the upstairs living room.

Check with your local utility company. When I built my shop here in Idaho a few years ago, the utility company added a separate power run to my shop. The shop is on it's own meter and has it's own 200 amp service panel. The utility company didn't charge for running power to the shop. I get one bill with 2 different meter readings.

My cost was the service entry, meter base, service panel and wiring. I bought the materials locally and wired the shop myself with everything inspected for code compliance.
Thanks Ken,
Good idea to contact xcell, and see what my options are there. one of the other things I was considering, was a new meter and an upgrade to 200 amp service to the house. Then splitting off what I needed for the sub panel.
Again, the proposed power requirements for the shop would be sort of "light weight". Nothing on the order of 3hp unisaws or dust collection, everything is 110vac except for the Inca and the table saw.

So it looks as though a 200 amp service is a minimum I guess?

[Peter Aeschliman]

For your shop tools, make sure to look at the amperage as well as the voltage. It's impossible for us to recommend the panel size without it. Make sure to account for start-up amperage too- you need to add some head room since motors often draw a lot more upon startup than they do when they're at cruising altitude.

At a minimum, I imagine you would be running your lights, an A/C or heater, a dust collector, and one machine at any given time. You need to size your requirements based on that demand, plus probably 20-30%.

My layman's understanding of a sub-panel is that it's not magic in terms of creating more power. You're still simply limited a total of 100 amps. So I agree with Ken- I really don't see a way for you to run a shop without some kind of total electrical service upgrade. And while you're at it, you really should consider giving yourself a lot more headroom. You may want to upgrade to bigger machinery in the future- it would really stink to have to redo your electrical again to do that.

I have 200 amp service to my 1,500 sqft and I only have two slots left in my panel. I'm planning moving my shop from an out-building on my parents' property to a "new" shop in the basement. I will have no choice but to get a second meter, but I'm thinking about doing 200 amps to my new basement shop even though my current shop has 100 amp service and running 30 amp circuits and 10 guage wire to each of my 220 volt machines, even though only my DC and heater require that much power (all of the rest only need 20 amps max). This way I can upgrade my outlets for bigger machines that I'll talk my wife into someday. ;-)

[Joe A Faulkner]

You should check with someone who knows the codes in your area. You might get the utility company to do as Ken described - run a separate meter to your shop. I doubt that they would run anything less than 100 amps which for what you describe as the plans for your shop is more than adequate. If you are going to run a sub-panel off your main panel in your house, I'm guessing (emphasize guessing) that your local code may require you to upgrade your house service to 200 amp. You could likely get by quite easily with a 60 amp sub-panel in your shop. A 15 amp circuit for your lights, a couple of 20 amp circuits for your outlets. I'd want to size the sub-panel to support expansion to allow for one or two 20 or 30 amp 220v circuitis just in case you grown into a 220v table saw, band saw, planer, jointer or dust collector.

[Brian Henderson]

Also, don't just plan for what you have now, but what you could have in the future. Just because you don't have any terribly power-hungry tools at the moment doesn't mean that in a year or two, you might not. Always get more than you think you need because you never know what tomorrow might hold.

[John McBride]

Also, don't just plan for what you have now, but what you could have in the future. Just because you don't have any terribly power-hungry tools at the moment doesn't mean that in a year or two, you might not. Always get more than you think you need because you never know what tomorrow might hold.

All great responses. Thanks guys. It should me mentioned, that there will be major changes in the not too distant future. A new garage/shop will be in the offing in the next 2 years or so. So the plan I am working on now, is just a stop gap until the new space is built.Still, the 200 amp main service vs. a seperate metered drop is one to ponder. I think that the 200 amp upgrade to the house, with a sub panel to the garage, is probably the best route right now just as Joe described.

[Lee Reep]

When we moved into our house 30 years ago, it only had 100A service panel. Our builder supposedly cut corners on the last phase, since our model was supposed to have 150 or 200A service, and the smaller models had 100A service. I had room in the main panel, and an electrician put a 60A breaker in the panel to feed a subpanel in the basement for my shop. When we added AC to the home a few years later, the electrician said we needed to upgrade. He installed a much bigger panel, but put in a 150A main breaker. Since he had bid the job, and could not raise his price, I think he settled for what he could get away with (150A vs, 200A). We have several spare slots in the main panel, and my shop has plenty of room in the subpanel, since I went with the double breakers (Square-D, 2 breakers in the space of one) years ago that save space. Our main panel has a lot of the older single breakers, and space could be freed up by going to the new style double breakers. I cannot imagine ever needing to upgrade.

I have plenty of power for multiple 20A 110VAC circuits (currently 4), and multiple 20A 240VAC circuits for table saw, radial arm saw, and dust collector. My compressor is in the garage, and powered there, with air distribution into the shop. I also have other circuits in the subpanel for lighting and a finished exercise room adjacent to shop. Now if I had a half a dozen people in my shop, all running tools, the panel would likely get overloaded and trip, but I've never popped a breaker in 25 years in my shop from overloads.

Given the opportunity to redo it, I'd probably go with 200A main, and 100A subpanel, but what I've got works pretty well for me.

[John McBride]

When we moved into our house 30 years ago, it only had 100A service panel. Our builder supposedly cut corners on the last phase, since our model was supposed to have 150 or 200A service, and the smaller models had 100A service. I had room in the main panel, and an electrician put a 60A breaker in the panel to feed a subpanel in the basement for my shop. When we added AC to the home a few years later, the electrician said we needed to upgrade. He installed a much bigger panel, but put in a 150A main breaker. Since he had bid the job, and could not raise his price, I think he settled for what he could get away with (150A vs, 200A). We have several spare slots in the main panel, and my shop has plenty of room in the subpanel, since I went with the double breakers (Square-D, 2 breakers in the space of one) years ago that save space. Our main panel has a lot of the older single breakers, and space could be freed up by going to the new style double breakers. I cannot imagine ever needing to upgrade.

I have plenty of power for multiple 20A 110VAC circuits (currently 4), and multiple 20A 240VAC circuits for table saw, radial arm saw, and dust collector. My compressor is in the garage, and powered there, with air distribution into the shop. I also have other circuits in the subpanel for lighting and a finished exercise room adjacent to shop. Now if I had a half a dozen people in my shop, all running tools, the panel would likely get overloaded and trip, but I've never popped a breaker in 25 years in my shop from overloads.

Given the opportunity to redo it, I'd probably go with 200A main, and 100A subpanel, but what I've got works pretty well for me.

Thanks Lee....good to know.

[Ole Anderson]

With a shop the size of a one car garage, under 300 sf, you can only get so many tools in there and a 60 amp sub panel should serve you nicely, however for almost the same price I would install a 100 amp panel as they are more common. The electric co may allow you to tap into the meter box and run an underground line to the new shop, new and existing panels off one meter. Depending on service drop size, the electric co may need to upgrade your service. That way all you may have to replace is your meter and not get into pulling and rewiring your house panel. Not that it wouldn't be a good idea at some point to do that. At least around here I see a lot of 2 pole 50 amp services run off the meter box for hot tubs and have done it myself twice, not sure it is ok to do that with a new panel. I presume that your panel and meter are only 20 feet away from your shop? That makes it easy.

I built my 1500 sf home 40 years ago including doing all the electrical under a homeowner permit and I am really glad my engineer buddy, whose dad was an electrician, talked me into a 200 amp panel. Really seemed like overkill at the time, but it is full now. Guess I was ahead of the curve.

[John McBride]

With a shop the size of a one car garage, under 300 sf, you can only get so many tools in there and a 60 amp sub panel should serve you nicely, however for almost the same price I would install a 100 amp panel as they are more common. The electric co may allow you to tap into the meter box and run an underground line to the new shop, new and existing panels off one meter. Depending on service drop size, the electric co may need to upgrade your service. That way all you may have to replace is your meter and not get into pulling and rewiring your house panel. Not that it wouldn't be a good idea at some point to do that. At least around here I see a lot of 2 pole 50 amp services run off the meter box for hot tubs and have done it myself twice, not sure it is ok to do that with a new panel. I presume that your panel and meter are only 20 feet away from your shop? That makes it easy.

I built my 1500 sf home 40 years ago including doing all the electrical under a homeowner permit and I am really glad my engineer buddy, whose dad was an electrician, talked me into a 200 amp panel. Really seemed like overkill at the time, but it is full now. Guess I was ahead of the curve.

At some point, the main service panel at the house DOES need to be upgraded to 200 amp or possibly more. I dont know for sure.
However, My immediate needs require me to bring power over from the exsisting 100 amp service panel. (I have been up late last night researching this, so forgive me if I am not exactly making sense)

So, in the absense of replacing the main service panel with a 200 amp service, I have been looking hard at putting a 60 amp breaker in the current (no pun) 100 amp service panel, pulling a line over the 20 or so feet to the garage and dropping it into a sub panel (with seperate 60 amp breaker main switch?).

From there, it would be one 220vac circut with two outlets. One at the table saw, and one at the Jointer/planer. One 15 amp circut for the shop lighting, and one 20 amp circut for the 6 outlets (20 amp plugs) to be spaced along the shops perimeter.

Questions,
Is this correct sounding? I am not looking for the "official" thumbs up, just spitballing here. I am looking for someone to either say "yes, you SEEM to be on the right track and would most likely NOT burn your shop/house down if you do it this way" or, " you are a moron forthinking of doing it this way, and any electrition who agrees to do it this way is a moron too".

Assuming I am NOT a moron, can anyone look at this electrical "map" and give me wire sizes for each portion?

Thanks,

[Ole Anderson]

My concern would be putting a 60 amp 2 pole breaker in what is probably an already fully loaded 100 amp panel. That is why I suggested going from the meter box instead of the panel. Meter box to fused disconnect (may or may not be required) to new panel. Be sure to get a permit so all is done per code and inspected. Only dicey part is working in a hot meter box. Even after you pull the meter, the incoming lugs are still hot.

[John McBride]

My concern would be putting a 60 amp 2 pole breaker in what is probably an already fully loaded 100 amp panel. That is why I suggested going from the meter box instead of the panel. Meter box to fused disconnect (may or may not be required) to new panel. Be sure to get a permit so all is done per code and inspected. Only dicey part is working in a hot meter box. Even after you pull the meter, the incoming lugs are still hot.
Well, that is a slight concern. Ill need to recheck the service panel, but I seem to recall that the Panel still has several open slots available. That may be a bit like saying "How can I be over drawn? I still have checks left in my checkbook", so some verifying of what is being drawn from the panel is, indeed in order.

[Andrew Hughes]

John, in my shop a have a 100 amp sub panel, a #4 wire runs from my main panel to my sub panel.The wire is protected with a 70 amp breaker at the main.
The biggest pig machine is a toss up between the bandsaw and jointer.both have 220 30 amp breakers.So I think your on the right track.
seems like everyone is trying to get you to go as big as you can,Cause it's a pain to do it later if you need to.Hope this helps.Aj

[John McBride]

John, in my shop a have a 100 amp sub panel, a #4 wire runs from my main panel to my sub panel.The wire is protected with a 70 amp breaker at the main.
The biggest pig machine is a toss up between the bandsaw and jointer.both have 220 30 amp breakers.So I think your on the right track.
seems like everyone is trying to get you to go as big as you can,Cause it's a pain to do it later if you need to.Hope this helps.Aj thanks AJ. Yes, I agree that it would be best to go big or go home. But this is just going to be a stopgap shop until the "real shop" gets built. Or, I find shop space at a reasonable price. Either way, there will be plenty of time to go big once one of those two things happen.

In the mean time, I just need to get appropriate power to the space I do have as best I can with what I have to work with. Thank god, I have at least enough room in the service panel, to bring some power over to the garage.

[Mike Heidrick]

Well, that is a slight concern. Ill need to recheck the service panel, but I seem to recall that the Panel still has several open slots available. That may be a bit like saying "How can I be over drawn? I still have checks left in my checkbook", so some verifying of what is being drawn from the panel is, indeed in order.

When you call the power company and ask for the meter to be pulled you can also request a dosconnect at the street or wherever. They will then disconnect the service at the transformer as well. Then no hot lugs at the meter base.

[William C Rogers]

All great responses. Thanks guys. It should me mentioned, that there will be major changes in the not too distant future. A new garage/shop will be in the offing in the next 2 years or so. So the plan I am working on now, is just a stop gap until the new space is built.Still, the 200 amp main service vs. a seperate metered drop is one to ponder. I think that the 200 amp upgrade to the house, with a sub panel to the garage, is probably the best route right now just as Joe described.


When I built my house last year I went with a 400 amp service with a 100 amp sub panel to my shop (75 feet from the house). I'm not suggesting 400amp, however when I had my shop in Indy I had 2 meters. The electric rates there were based on usage. So I was paying 1/2 as much as the house for much less usage. If you look at two meters you might want to check with your electric company on the rate structure.

[Jim Seyfried]

If you look at two meters you might want to check with your electric company on the rate structure.
I built my pole barn before I built my house and have a 200amp service to each. Here the power company does charge extra for the pole barn. The daily use makes an easy comparison. From recent bills I found I paid $2.32 for 12kWh for the PB and $3.74 for 25kWh for the house. That is about $0.50 extra per day for the same amount of electrical use. At that usage it costs me an extra $180 a year! (now I wish I hadn't figured it out) When I used it for a construction business it made it easy to keep track as an expense though. I just ran natural gas to the PB and went through this type of calculation for that. It would have cost an extra $14 a month just for the meter plus extra for the gas, so I ran it from the house even though it was twice as long of a run.

[John Donhowe]

John-

Given your circumstances, IMO you're on the right track. First, I assume that 100 amps is sufficient for your current overall household needs. Keep in mind that the 100 amp limit is based on the total usage at any given time, which could be exceeded if you're running a lot of high usage units all at once- electric water heater, A/C, electric range and oven, electric dryer, hot tub, electric heat, etc., etc. Assuming you're not doing that, figure out what appliances you would conceivably use simultaneously, and figure out how much "headroom", i.e., more amps you can use and still remain less than 100 amps.

In the same vein, running a line from your main box to a 60 amp panel in the garage makes a lot of sense to me. It will give you a lot of flexibility in adding a bunch of circuits in your garage. Bear in mind that you'll almost certainly never use a full 60 amps- most likely no more than 30-35, with one power tool and maybe a dust collector, plus lights- no worse than running a dryer.

Sure, who wouldn't want the flexibility of 200 amp service, but if this is a stopgap measure anyway, it makes sense to me, and I think would be sufficient for future upgrades, both to tool needs and upgrades to incoming house service. JMHO, as a non-electrician, but who's done several rewiring projects over the years. Good luck!:)

[John McBride]

John-

Given your circumstances, IMO you're on the right track. First, I assume that 100 amps is sufficient for your current overall household needs. Keep in mind that the 100 amp limit is based on the total usage at any given time, which could be exceeded if you're running a lot of high usage units all at once- electric water heater, A/C, electric range and oven, electric dryer, hot tub, electric heat, etc., etc. Assuming you're not doing that, figure out what appliances you would conceivably use simultaneously, and figure out how much "headroom", i.e., more amps you can use and still remain less than 100 amps.

In the same vein, running a line from your main box to a 60 amp panel in the garage makes a lot of sense to me. It will give you a lot of flexibility in adding a bunch of circuits in your garage. Bear in mind that you'll almost certainly never use a full 60 amps- most likely no more than 30-35, with one power tool and maybe a dust collector, plus lights- no worse than running a dryer.

Sure, who wouldn't want the flexibility of 200 amp service, but if this is a stopgap measure anyway, it makes sense to me, and I think would be sufficient for future upgrades, both to tool needs and upgrades to incoming house service. JMHO, as a non-electrician, but who's done several rewiring projects over the years. Good luck!:)

Thanks John. I kind of thought so too. The real need in the garage is powering the Inca jointer/planer, the table saw, and some sort of 110v dust collector. One of those, and the ... Say shop vac as dust collector, would be the only things being run at the same time. Add to that lights, and 6 outlets, pretty much is what is needed for the shop to be use able.

Sure, I would love to have huge powe, and full size production machines, but for what I am doing this set up gets me rolling and productive.

[Chris Friesen]

Something to consider...you could design the subpanel and feeder line with the assumption that it'll be upgraded later, then feed it through a breaker on the main panel sized for what you *need* (and can spare) currently.

Also, you may not really need to upgrade your main service. For comparison, I've got a 1230 sq foot house with a 100A service and I've never popped the main breaker in 9 years. I've got a 3HP planer, 3HP cabinet saw, 2HP Bandsaw, 8" jointer, drill press, small compressor, 1.5HP dust collector, 16 120V outlets, 5 240V outlets, and a bunch of 4'-T8 lighting. The shop is powered via a 100A panel that is fed by a 40A breaker in the main panel.

I'm in the Canadian prairies so my A/C demands are relatively low, and I've got gas heat. But my range and clothes dryer are electric.

And as another data point, when I wired my shop it was cheaper for me to buy a regular electrical panel (where the panel has a main breaker) than to buy a special subpanel. The regular panel came as part of a bundle with a bunch of breakers (of whatever sizes I wanted), and the main breaker on my subpanel is a convenient way to "safe" most of the power tools.

[Steve Peterson]

I ran my shop with no problems on a 50A sub-panel. This works just fine for a 1 person shop. John's 12x24 shop sounds like a 1 person shop. Mine was around 400sf.

The largest load that would be running at the same time would be a 5hp tablesaw, a 5hp ClearVue dust collector, a 120V window air conditioner, 4 4' double tube fluorescent lights, and a ceiling mounted air filter. I made sure to keep the air conditioner on a different circuit than the other 120V circuits that will be on at the same time. This prevents overloading one leg of the 240V lines.

The only other limit is to wait for the ClearVue to come up to speed before turning on the tablesaw. I am not sure if one 50A breaker would have enough power for both 30A loads to start up at the same time. Running currents are less than 20A for each. If I had a choice, I would have selected a 3hp tablesaw.

Steve

[paul cottingham]

For what it's worth, I run my whole house, including my heat pump, and electric hot water tank, on a 125 amp service. Never been a problem, and my monthly bill reflects that I never approach the limit of my service.

Mind you, I am a mostly hand tool guy, but I do run a saw, planer and jointer with dust collection regularly.

[John McBride]

For what it's worth, I run my whole house, including my heat pump, and electric hot water tank, on a 125 amp service. Never been a problem, and my monthly bill reflects that I never approach the limit of my service.

Mind you, I am a mostly hand tool guy, but I do run a saw, planer and jointer with dust collection regularly.
Thanks guys. Based on what the electrition says, 60 amps is fine for a sub panel for the shop. There is plenty of room in my main service panel he says. Looks like I am a "go" to power up the shop. Now....just need to pay the electriction