@charlesA - Ha Ha Ha
@oxyolk - You nailed it.

In the very near future lighting loads will shrink to very low Amps because of LED's

Put a 20 Amp breaker feeding each and every outlet!!!
That is one 12-2 cable per outlet!!!
Trust me you will not regret doing this, wire is cheap breakers are cheap, Frustration resetting breakers - you put a your price on that one.

I speak from experience - why? Because I have done none of the above, and I should know better!

 

Keep in mind that when you say one breaker per outlet that in a garage you are required to have GFCI on each 110v outlet. GFCI breakers and outlets do start to add a lot to the cost when you add several outlets. Don't get me wrong I do agree with more circuits but it depends on what the budget is and if this is a permitted job or not. The other factor to consider is how difficult is it to add another circuit later on if you find out that you are blowing breakers.
Mike

 

GT350, you're required to have GFCI on each circuit that has multiple outlets (you can do a single-outlet without GFCI, as you might to a dedicated freezer), but you can do that with one GFCI outlet and chaining the rest of the outlets off of that one GFCI.

You just can't do that with a shared neutral (aka "Edison") circuit. For that you need something that measures the current across both hot legs and the neutral, and that's the $80 circuit breaker. Rather than the $12 GFCI socket.

Oh, and I'm not nearly as dogmatic as exelectrician about one breaker per circuit, but for the love of all that's holy don't ever put anything but lighting on your lighting circuits. It sucks to blow the circuit and be left in the dark.

 

I haven't had to do any code classes in quite some time but I believe in a garage any 110v outlet has to have GFCI doesn't it? I think that what you are talking about is like a permanent piece of equipment such as a microwave mounted above a stove.

You and I are talking about the same thing when you said chaining them together , maybe instead of 1 circuit for each outlet you have 1 circuit for two outlets, depending on what you plan on running, that just cut the GFCI costs in half. If the budget is not a concern and you have enough breaker spaces then by all means 1 circuit per outlet in a shop would be best.

 

Whoops! I believe you are correct, a web search suggests that as of the 2008 revisions there is now no exception for GFCI circuits in the garage! (Which is interesting, 'cause I had an electrician run 110v washer and dryer circuits in my garage in 2008 and neither of those is GFCI protected, and I know they were inspected. Maybe the code hadn't filtered down that far yet.) I stand corrected. (And, anyone with a freezer or fridge in the garage would probably do well to get an alarm for it!)

 

I put in a 40amp sub panel with two 15 amp circuits and one 20 amp. You are not going to run ALL your tools at the same time. I run a fan continually and have the vacuum on its own circuit. The 20 amp handles the big tools (one at a time)

 

In a previous life I was an electrician. A 200a panel will be a waste of money even with a heat pump running. Several lighting circuits so that if a tool fails and trips a breaker you are not in the dark. Outlets should all be 20A and use high grade outlets. Single circuits for TS, DC, Air compressor and HVAC. In my shop I have a quad outlet box every 8 feet on the wall, 2 circuits for each side of the shop with one outlet on each box on one of the 2 circuits. I have a shop vac that I use as a filtered air blower. The very most I have running at one time is the shop vac, DC and one other tool. The TS is probably the highest amperage of the other tools. In this equation, lights are of little impact. Mine are all CFL and as they burn out I will switch to LEDs.

So what you need to calculate is the HVAC, TS and DC. Please remember that the amperage or wattage listed on the nameplate is the maximum that it would draw, not necessarily the running current. If you have leaky air
Lines then it wouldbe possible to have it run at the same time as everything else. Mine are very tight so I do not figure this in.

BRuce

 

My HVAC calls for a sixty on the furnace and a forty on the pump. He probably doesn't have that concern, but that wouldn't leave a lot on a 100 amp panel. Add my cabinet saw, collector. . . .

All that said, it sounds more and more like a hundred amps would be fine for this needs.

 

No worries. I have a single 20A circuit in a 3-car garage. Lights are on something else. Obviously for safety reasons I don't run more than one thing at a time. But when I run a planer or jointer, I have the vac going to collect the bits. Even that doesn't pop the breaker unless the tool bogs down. Not recommending this, just sayin'. If you have 2 or 3 circuits it should be more than enough. Oh yes, if I need to run an electric heater in the winter I just shut it off when I'm using vac to collect chips. Otherwise the single 20A circuit works.

 

I use a separate breaker for each 22V receptacle. I have half my lights on one circuit and half on a second circuit. I have a 110V breaker for each wall of my shop. I work by myself most of the time. I have had no problems with breakers tripping. I use a Square D 100 amp panel. The 220 breakers eat your space as other have said. I have 220V dust collector, unisaw, air compressor, planer and welder receptacles. As you can see that alone is 10 spaces. Then I have the 4 wall and 2 lights. I also added a new room and have some 110 over there. It just takes space.

 

Most everyone is steering you in the right direction. I'm curious, what size is the service for your home? Are there empty spaces or spare breakers in your panel? The answers to these questions may limit your options without further upgrades.

 

I've been working on clearing out the garage and finally had the electrician come last week and got the quote today. After everyone was talking 200 or 400 amps in the main panel, I thought maybe I was misreading my main breaker and thought I had plenty of room to grow. But as it turns out, I've only got 100A service in the main panel! The electrician said they can only get 60A to the subpanel, but based on what most of you have said, I think that will be enough for me to get by in my small 1-car garage shop. At most I'll be running the table saw, dust collector/shop vac, air compressor, and either a window A/C or a space heater. Even with all that I should have a little breathing room, and it should be pretty rare that I'm running everything simultaneously.

Here's the breakdown in case anyone else is curious…although I'm sure prices can vary wildly by region:

1. Install and furnish a 60A sub panel in garage. $655.00
2. Install and furnish 4 20A 120V receptacles in garage. $355.00
3. Install and furnish 2 20A 220V receptacles in garage. $175.00

To me the quote doesn't seem very detailed, but it sounds like they'll just ask where I want the outlets when they come to do the work. I did email them asking a couple more questions though and the 120V receptacles are 2 per circuit.

I had also wanted a dedicated lighting circuit, but I guess the 60A panel is already full so I'll have to figure something else out. Maybe I'll just put the lights on the existing garage circuit.

I'm tempted to ask for a quote to upgrade the main wiring along with running 100A to the garage, but the most practical solution is probably to move to a house that already has a 100A subpanel in a bigger, heated garage.

 

Seems totally reasonable price-wise, probably based on running surface conduit for your sockets. You might want to clarify on the "where" with them, it's easy to run conduit along the wall where the panel is, harder to run it to the opposite wall.

And, yeah, the lights on the existing garage circuit is fine: Modern lighting is taking less and less power all the time; I think code says 1 lighting circuit per about 800 square feet habitable (garages are weird in that calculation), and between the CFLs and LEDs, I could turn on every single light fixture in my house and I don't think I'd break an amp and a half. It's just that when the router inevitably bogs down and you blow the breaker, you don't want to have to find the panel in the dark.

 

First of all running a machine on 240 doesn't mean it uses less amps. Thats a myth. you are just drawing it from 2 places instead of 1, allowing you to use smaller wire. "amps x volts = watts" Power is power whether it's 120 or 240.

Second of all you can set any size panel you want, but you will never draw more amps than you have coming into the house. So if you have 100 amp service thats all you will ever get. Setting a larger panel will allow more breaker spots, but thats all.

Third is just my opinion. A 100 amp panel should do all you will ever need, and setting a sub panel is the smart way to go. Personally I am not a fan of conduit running all over. I like everything in the wall, it justs looks and stays cleaner.

I have a 60 amp panel in my shop. I wish I had more room. On 240V I have a 3hp TS, a 3hp DC, a 2hp jointer, a 5hp compressor, and a 10hp RPC (rotary phase converter) for my 5hp 20" planer they run together. I have the 120V 20 amp outlet split half and half, and the light on their own circuit. With the lights on I have run the DC, planer, TS, and the jointer all at the same time. I was making trim and it was easier to leave the machines running then start and stop. I have never blew a breaker in 7 years. For the service wire I use #4 aluminum with ground. To those that are sneering at the thought of aluminum wire take a look at the wire from the pole to the house, Yup it aluminum and probably #4. I have my machines paired based on what they are and how they are used. The DC and compressor (30 amp circuit), the jointer and TS (30 amp circuit), finally the RPC and planer (50 amp circuit) witch also services the welder when needed.

 

Shawn, I Agee with your assessment and you are correct there is nothing wrong with aluminum for sub panels and even ranges. I don't like to use it for dryers or 15/20 amp circuits. With today's allot terminals, there is not the issues there was 40 years ago.

BRuce

 

I'd get a meter base installed with a 200 amp service. Doesn't cost much more and leaves you with lots of options. You could add water heater, heat pump, big honking compressor, etc. I would suggest that you not install any 15a circuits.
One of the problems I see on here often is someone having trouble with their TS tripping the breaker. Probably because of the feeder size and length going to their shop. To me it's also a safety issue too. Saws lose hp and stall or kickback.
A good rule of thumb - if a wire is ran more than 50' you probably want to increase the size.
I'd put the dust collector and air compressor on a separate circuits.

 

Shawn, good advice. If you're running all that on 60A, I'm pretty sure I can run my little shop on 60A!

I didn't realize you could run 240V on shared circuits…I thought I read somewhere that 240V circuits had to be dedicated, but maybe that was just someone's recommendation.

I'm not sure I follow your argument about amps. Power is measured in watts, and if the wattage is to remain consistent, the "amps x volts = watts" equation mathematically requires you to draw less amperage if you're running at higher voltage. For example: 120V x 20A = 240V x 10A

But if you look at a 120V saw and a 240V saw, they might just happen to draw about same number of amps because the 240V one has a more powerful motor (e.g., 1.5hp vs. 3hp; 1hp ~ 746W). Is that what you were getting at?

 

Cutworm, do you mean get a new meter and panel in the garage, or do you mean upgrade the main panel in my house so I can put a bigger subpanel in the garage?

When I measured, I came up with 70-80ft from the main panel to the new subpanel. I know code requires thicker cables for longer cable runs. I'm pretty sure the electrician will stick to code, so I should be safe there.

 

I am using #4 aluminum from the house to the detached garage (shop). If I remember right I have around 125' of wire. I don't know if I said this before but I advise you to use at least a 100 amp panel with 20 or more breaker slots. So you don't have to share 240V circuits. I am not sure it is legal by code to share outlets for 240V machines. As long as the wire is sized to match the breaker then I don't really see a problem. I am not a sparky, but I do have an understanding of electric.

If you look in your panel there are 2 "hot wires coming in from the pole". 1 is the 120v A phase and 1 is the 120v B phase. you need a hot leg from each one to make 240V. if you have a machine drawing 20 amps on 120V it is drawing it from 1 phase. If you have the same machine drawing 10 amps on 240V it is drawing 10 from the A phase and 10 from the B phase.

The easiest motor for me to read the name plate on is a 1.5 HP 3450 rpm Baldor motor. It was on the shelf.
It states at 115V it draws 13.2 amps.
next it states 230V it draws 6.6 amps.

"amps x volts = watts"

13.2×115 = 1518

6.6 x 230 = 1518

no matter what you do it will draw the same amperage total.

 

Sean, thanks for the explanation. What was confusing me was your statement, "no matter what you do it will draw the same amperage total," because to me it implies that you're drawing 13.2A @230V, despite the fact that you already illustrated that you're drawing 6.6A @230V. I think it just comes down to a matter of interpretation.

One interpretation says at 115V, the motor draws 13.2A on the hot wire and returns 13.2A on the neutral wire. At 230V, the motor draws 6.6A on the A leg and returns 6.6A on the B leg (both hot, but 180 degrees out of phase). So you have 6.6A x 230V = 1518W.

A different interpretation of the 230V case is that you're drawing 6.6A on the A leg and "drawing" 6.6A (180 degrees out of phase) on the B leg. If you go with this interpretation, you have to maintain that each leg is running at 115V even though the differential between the two legs is 230V. This is the part that wasn't obvious to me at first in your explanation. In this case, you have (6.6A x 115V) + (6.6A x 115V) = 1518W or, more closely to how you describe it, (6.6A x 2) x 115V = 1518W.

So I would clarify your statement, "no matter what you do it will draw the same amperage total," to read, "no matter what you do do it will draw the same amperage total across the hot 120V legs."

 

The more in depth explanation you made is exactly what I was aiming for. I am not the most well spoken person. I know what I am saying, but I can't always say it right. You got it though. As long as you understand that going to 220v doesn't mean you are using less power then thats where I was going. So If it helped then great, if not then sorry I couldn't be more help.