Yet another shop wiring question!

[Augusto Orosco]

I should add some background to make this clearer… my apologies if it gets too long.

I am a one man shop, not even a weekend warrior (maybe an “every other weekend warrior”), so only one power tool + dust collection can be used simultaneously. My shop is an attached 2 car unheated garage with concrete floors and 8’ ceilings. No plumbing or forced air into the garage.

After reading all the info here about the dangers of dust, I now always work with the garage doors and windows open and wear a cartridge respirator at all times while in the shop. For better “chip” collection, I am thinking of a 2HP DC that will vent outside (lucky me, I can vent out). The idea is that the DC would control chips and the open doors, windows and respirator should protect me from the fines. Maybe an air-cleaner will be added later.

So, now to the electrical issue:

Currently, all I have are two 15amp 110V circuits; one feeds the lighting, the garage door motors and one receptacle; the other one feeds exclusively one receptacle. The electrical panel in my house is 200amp, located in a basement wall adjacent to the garage (so, the shortest run from the panel to the garage is just the thickness of the wall). The panel has plenty of free slots.

Ideally, I would install a sub-panel, many breakers, outlets, and the like, but I don’t plan on staying in this house for more than just a few years; so I don’t want to invest too much money in a set-up that I will be leaving behind.

With the current set-up, the electrical demands of the lights, the shop-vac and small portable power tools are taken care off (no tripped breakers yet). So, I need to provide for the future machines.

I think that the maximum electrical demand would happen when running:

A) The 2HP 220v DC plus large 3HP 220V machine (e.g. a table saw)

Or

B) The 2HP 220v DC plus a large 110V machine (e.g. a 15amp router)

This is my initial thought: Install one 40amp 220v circuit, which will take care of (A) and one 20amp 110v breaker, which will finish to take care of (B).

The point that I am most unsure about is the 40amp breaker. Probably two 20amp 220v circuits would be better, but probably also more expensive? I am on tight budget here, so I want to reduce costs, but never at the expense of safety.

Any thoughts about the setup? Any ball-park ideas about costs? Do you know a good electrician that serves the Boston area (south shore)?

Thanks, and sorry for the lengthy post!


P.S. I forgot to add that I know very little about electricity, so everything will be done by a licensed electrician. But to have input in advance from some of you, will make me much better informed when I ask for estimates and discuss options with the electrician.

[Anthony Whitesell]

Since you don't plan on staying more than a few years (I said that too, seven years ago), I would do the least amount possible, but don't short change yourself. With that said, I would run 1 dedicated 220VAC circuit for the dust collector and one multi-outlet 220VAC circuit for the tools. With this you won't ever have to worry about tripping a breaker due to the combined amperage of the DC and a tool. Since the lights are already wired you don't have to worry about a circuit for them. I would run one (or maybe two) 15 amp 110VAC circuit(s) for the smaller tools.

Most people will suggest that you put the outlets up higher (52"). After last night, I suggest that you put them just an inch or two below the height of the table saw bed. Once upon a time I had the standard height (~18") outlets, they were a pain to get to and not easy to see if the tool was plugged in. On someone's suggestion I raised them up. Last night I was ripping a piece of the tablesaw and happened to catch the cord and unplugged the saw while it was running. Luckily I didn't shorten the wire when I moved up the outlet, and plan on moving them down just below the height of the tablesaw (and the bandsaw, planer, and jointer); to a height that will be protected by the equipment itself.

[Chris Padilla]

Well, for starters, I would just make the 240V circuit a 30 A one (#10 wire). You won't ever need more than that from a 240V circuit I'm pretty sure. I'm not sure I've ever heard of a 240V/40A plug...at least not from NEMA. Google "nema plug chart" and you'll see what I mean. That will cost you two slots in your panel. You may wish to visit your local Home Depot or Lowes and just peruse the different breakers they have and you'll get some ideas how to best spend your money for breakers in your panel. There are lots of choices.

[Augusto Orosco]

Thanks, Steve and Chris... that saved me the embarrassment of asking the electrician for a 40amp breaker.

So, it should be two 30amp (#10 wire), one for the DC and one for the 220 machines? Why not two 20amp circuits? All the high HP machines I have looked at (never more than 3HP @ 220; can’t fathom ever going higher) stated a suggested 20amp circuit, for motors that are rated as drawing between 13 and 18amps.

[Chris Padilla]

240V/20A is fine if you really feel you won't need anything larger. Overall, it'll be a *tad* cheaper running #12 over #10 but if you are having a pro wire this for you, I bet the cost won't be much different. Ask him for 240V/20A, get the quote, and then ask for 240V/30A.

[Anthony Whitesell]

Cesar, you'll need to plan for worst case. 18 amp and 18 amp is 36 amps. I think you're your better off with the two 20 amp circuits.

I only have 110VAC available to me, and more often than not I would trip the 20 amp breaker trying to start my 1HP TS while my 1HP DC was running. Obviously, the DC and TS need to run at the same time.

[Peter Quinn]

Sub panel in garage is the best approach. Given short wire run to main panel also the most costly. Sucks leaving the garage to reset a breaker should it ever be neccessary. Nice having a manual disconnect in the shop for maintenance without having to unplug machines (mine are all on twist locks)

Either way, I'd seperate the garage door opener from the lights. Garage door opener=1 15A circuit, lights and a utility receptical=1-15A circuit. 110V powertools at 15A=1 20A circuit, 220V Dust collector= 1 20A or 1 30A circuit, depends on the machine, large stationary 220V machines=1 30A up to 3HP (table saw takes about 23Amps continuous if I recall corectly) Fused manual disconects for each 220v circuit at point of use provides decent circuit protection and convienence. Costs about $40 per disconnect. I would not run one 50A220v circuit for multiple simultaneous machine use; wire and breakers are just not that expensive.

PS I am not a professional electritian, but I play one at home!

[Rod Sheridan]

Hi Cesar, if it were me I would probably go with the following;

1) A dedicated 240V circuit for the dust collector, either 15A or 20A depending upon the motor full load amperes. Ignore horsepower in discussions, the full load currents of motors can vary as much as 50% depending upon the motor.

2) A 15A or 20A 120/240V feed to all the other receptacles in the shop depending upon the motor rating of your largest tool, probably your table saw.

This would give you two 120V 15A or 20A circuits for 120V tools, and a 15A or 20A 240V circuit for your machinery.

Unless you purchase a 5 HP motor on a machine (not needed at home), or you have a really inneficient, low power factor motor, you will be fine.

That means only two runs of wire, and two double pole circuit breakers. No need for a sub panel or disconnect switches.

Regards, Rod.

[Jim Thiel]

My shop is an attached 2 car unheated garage with concrete floors and 8’ ceilings.

Ideally, I would install a sub-panel, many breakers, outlets, and the like, but I don’t plan on staying in this house for more than just a few years; so I don’t want to invest too much money in a set-up that I will be leaving behind.

Two thoughts here: It's a shop space, not a utility closet. Put in the outlets so you can work without tripping over extension cords, or needing to work at a certain location because that is the only place the router will reach.

Second, a house is not an investment. It is shelter for your loved ones and things. The added value of a fully electrified shop space is and should be worth the initial costs. When the next guy walks through the house, moaning about trimming the bushes and he doesn't like your flowers, everything will stand still when he sees your shop space. He will see himself in that space, using his tools, and wondering out load why his wife can't see the potential in the lime green tiles in the foyer.

Jim

[Augusto Orosco]

Two thoughts here: It's a shop space, not a utility closet. Put in the outlets so you can work without tripping over extension cords, or needing to work at a certain location because that is the only place the router will reach.

Second, a house is not an investment. It is shelter for your loved ones and things. The added value of a fully electrified shop space is and should be worth the initial costs. When the next guy walks through the house, moaning about trimming the bushes and he doesn't like your flowers, everything will stand still when he sees your shop space. He will see himself in that space, using his tools, and wondering out load why his wife can't see the potential in the lime green tiles in the foyer.

Jim

Thanks, Jim. I realize now that my statement regarding the "subpanel, breakers and outlets" was misleading. The outlets will go in; I am not planning on having a web of extension cords around the shop. My issue was with the number or circuits to install (and my personal decision of not installing a sub panel).

I also love my family very much; and that's why I will make sure that whatever I end up doing will not jeopardize their safety in any way. I don't expect to make money once I move. If I do, great, if I don't that's fine, too. All I want for the future is an even better house for my loved ones (and a bigger space for my shop!) I have been thinking about my electrical needs for quite a while already. Every dollar I spend in wiring is a dollar I can't spend in wood/tools and viceversa. I am just trying to strike a balance I feel happy with.

[Wade Lippman]

The cheapest thing to do is to change the circuit with the single outlet on it to 240v. You won't be able to run your 2hp DC and 3HP TS, but it will buy you some extra capacity for $20.

[Jack Porter]

Hey Cesar,
I am just outside the boston area and am in the process of the same project. A friend of mine is a licensed electrican and didn't mind me pulling wires myself and installing outlets and EMT conduit (I've done this on other projects). The most expensive part of the project for me was the #6 wire for the subpanel, about 50 ft, but you don't have this issue. It sounds like our shops are somewhat similar, I run 2HP DC, with either TS, BS, router, etc. and I don't forsee any issues with my under-construction setup.

I'm putting in an 8 slot subpanel one circuit 20amp 220 for the DC, one circuit 110 20amp for contractor TS and BS neither of which would be on at the same time, and a third circuit 20amp 110 with 5 outlets for various handtools etc. Lights and one additonal outlet are on a direct feed from the main 200amp sevice.

This would have cost me about 700bucks, but doing a lot of the work myself, I'm only paying my buddy to install the subpanel, connection to 3 circuits at subpanel, and conneciton to main box.

Expect to pay an electricain about 100 buck an hour in this area plus materials. Shoot me a PM and I'll give you my friends info.

Sounds like you could do this project for a reasonable price using Rod's suggestions. If you don't mind exposed conduit and surface mounted outlets, an electricain can throw those in a heck of a lot faster than snaking wire through finished walls and ceilings. Also it's something you can probably do yourself and save a few bucks.

[Steve Rozmiarek]

Ok I can't resist, as per the moving electrical ?'s to a seperate place thread, are you all licensed electricians and has all your advice been substantiated, in writting, by all pertinant agencies with oversight, and has the disclaimer statement been signed in triplicate?

[Jack Porter]

Ok I can't resist, as per the moving electrical ?'s to a seperate place thread, are you all licensed electricians and has all your advice been substantiated, in writting, by all pertinant agencies with oversight, and has the disclaimer statement been signed in triplicate?

All signed off by the building inspector, oh wait, I needed a permit?

[Augusto Orosco]

Ok I can't resist, as per the moving electrical ?'s to a seperate place thread, are you all licensed electricians and has all your advice been substantiated, in writting, by all pertinant agencies with oversight, and has the disclaimer statement been signed in triplicate?

Don't worry, Steve, I will not hold anyone here accountable and everything will be up to code and inspected afterwards

Hey Cesar,
Expect to pay an electricain about 100 buck an hour in this area plus materials. Shoot me a PM and I'll give you my friends info.

Jack, thanks!. PM Sent.

2) A 15A or 20A 120/240V feed to all the other receptacles in the shop depending upon the motor rating of your largest tool, probably your table saw.

Rod, I am probably revealing my total ignorance with this regard by asking, but could you clarify? Are you saying that it is possible to run a 120/240 feed from one double pole breaker? That would make things much easier <edited: I get it now... just found it after checking my DIY wiring books>