Design for my garage shop

[krw]

That is pretty low, but I wouldn't mess with it unless you have to move/rewire it for some other reason.

:-)

[Nonny]

Just as a FWIW, let me admit to a minor boondoggle I did long ago. Let's just say that I have a bit of experience as an electrician wiring homes in the 60's, as a builder and as a woodworker. However, I can also screw up and am not ashamed to admit it.

When I wired my own shop, I pulled in a 60a line to a load center in my shop from my main household breaker box. I then got a

6-circuit little load center box and connected it up without much thought. The box had 3 breakouts on the left and 3 breakouts on the right. It was only when I began installing some tools that it hit me like a ton of rocks: that's just 2 normal DP breakers and 2 SP breakers. In my own case, it was a simple task to pull out the little box and substitute in a 12 circuit box with 6 knockouts on each side. The little box became a load center on one of the attics.

[Lew Hodgett]

-----------------------------------------

Lowest cost, highest flexibility as follows:

125A MLO (Main Lug Only) 12/24 (12-1" poles/24;1/2" poles) Load Center equipped with a 2P-60A Main c'bkr kit, neutral bar, and insulated ground bar.

The above has enough capacity for almost any shop including a fairly good sized commercial shop.

Install 2P-30A branch c'bkr for each 240V stationary tool along with a 2P-30A, non fused disconnect at (within 10ft) the tool.

If you are going to work on a tool, padlock the disconnect switch in the OFF position with a padlock that has only ONE KEY, which is in your pocket.

The above is a standard industrial safety practice.

Simple, neat, and low cost.

Lew

[Bill]

Nonny, Thank you for saving me from learning that lesson the hard way!

Here is a relavant DIY-type link I found, in case anyone else is interested:

[dpb]

Bill wrote: ...

No, that's what subpanels are for -- just size it for the number of circuits of the type you want/need and make it's service breaker the same or smaller than the feed. If it's close enough, you can (I think) get by w/o the local breaker/disconnect but it's certainly more convenient and I'd likely not scrimp...

Good luck, it ain't rocket science; most of the Code is simply formalizing what is common sense; it just takes somebody to point out what that commonsense is for the first time and NEC is the standard. The self-help books are pretty good in general at separating the code legalese and turning that into what actually needs doing...

--

[keithw86]

If they're in different locations I believe you're required to have a local disconnect. This can easily be accomplished by inserting a breaker, rated for the wire between the sub and main panels, into the panel and feeding it "backwards" (the electrons don't know the difference). This breaker should be marked clearly as the disconnect.

Yup.

[Swingman]

If you do what Lew said you will have no problems installing a sub-panel of the right kind that will be flexible and codeworthy (you haven't got into the issue of "grounding" a sub-panel yet, and, depending upon the location, you will most likely need to address grounding with an "insulated ground bar" which generally has to be purchased separately from the breaker box and installed therein).

Save yourself some time, money, and redoing, by paying particular attention to what Lew said!

Got the point yet?

If not, get it ... by doing what Lew said! :)

[Robatoy]

I think he should do what Lew said to do.

[Lee Michaels]

I think he should do what Lew said to do. ==================

Does that include the installation of the epoxy workstation?

[Robatoy]

. . . . . . .

you are mean......*smirk*

[Swingman]

Y'all go ahead and laugh, now! :)

I don't think it is apparent to the average person just how much experience and knowledge is behind that information, particularly with regard to the sub panel choice/type.

Trial and error on this issue can cost the neophyte beaucoup $$ ...

[Hoosierpopi]

1. Never enough outlets.

a) Try running 12/3 or to all you outlets, isolating the top from the bottom and adding a switch to the bottom outlets if not to top and bottom. This will allow you to leave those wall transformers plugged in 24/7, but turn off power to them when you leave the shop.

b) Duplex outlets in the ceiling can serve ideally for the four foot fluorescent "shop lamps" sold at Lowes, HD, etc for about $9. And you can do the switched approach on these as well in case you have a need for a DROP CORD approach to a tool - assuming your shop would not be usable with the lights off e.g. nto enough window area to let in sufficient daylight for working.

1. The wall on the house side might prove a treasure trove of points to secure power, telephone line, cable TV, water, sewer access. Is the floor of the shop even with that of the house/kitchen? Hey, how about a shop sink/eyewash station replete with drain?

[Bill]

Okay, Okay, I WILL DO as Lew suggested--and gladly too! : ) : )

He wrote:

Install 2P-30A branch c'bkr for each 240V stationary tool along with a 2P-30A, non fused disconnect at (within 10ft) the tool.

Question: So this redundancy is a good idea for 240v tools, but is not as important for ones powered at 120v (which are even more likely to be powered by conventional outlets wired in a series)?

Thank you, Bill

[Bill]

For extra measure of safety?

Yes, I like this idea. Switches here make good sense. I'd use more overhead-lights except that electric garage door opens right to the ceiling and the pull-down "stairway to the attic" blocks another good location for a light fixture.

You are right. It's a shame not to have (more than 1) outlet on that wall. The opposing wall I can tear down, and no one will care. The kitchen wall is sure to be full of insulation--and if it's insulated like the attic, it will be "full of fluff/lint" that looks like it came out of a vacuum cleaner. What do you think of the idea of cutting a 8" opening most of the length of the wallboard to install several electric boxes, and then replacing it?

I'd like to add outlets outside the garage too... As long as I'm making a mess, I may as well make it a big one! ; )

Thanks, Bill

[Bill]

Some of what I've learned since I read Lew's post the first time:

Evidentally, a load center is "Main Lug Only" when it doesn't have it's own main breaker like the primary load center would probably have.

Load Units, such as made by Eator Cutler-Hammer use descriptions such as "12 spaces, 24 circuits". If I learned part of my lesson yesterday, the only way you'd get 24 circuits would be to use 1 Hot and a 1 Common for every circuit. Is it typical for someone put two such circuits under a single breaker--probably not in a shop environment, huh? Even "lighting" seem too important to mess around with.

So you use 2 spaces for a 2P-30A branch For Each 240v stationary tool in the load center. So with four 240v tools one is basically left with room for 4 or 8 120v lines. This raises the question: Which is better--two circuits with 1 outlet each from 1 breaker or one circuit with 2 outlets on one breaker? I think the former--for the same reason Lew only wants one 240v tool on each line. This creates a new question for me: in what sense does a 15A breaker support two different circuits? Specifically, does it only support the sum of the amperages of the two circuits?

I try to learn Something New everyday. Today was certainly no exception! : ) Got to hit the hay for tomorrow's another day!

Bill

[Swingman]

You really don't need to install a disconnect for a dedicated circuit to each machine in your home shop.

Is your shop in a garage?

[dpb]

...

And a separate circuit for every stationary tool unless you're a production shop w/ an employee at every workstation continuously through a shift is _WAY_ over the top overkill...

For a home, casual-use workshop as I gather this is, one or perhaps two

30A 240V circuits will be enough w/ outlets judiciously placed for the major equipment you now have and some consideration given to what you think you may want to add in the foreseeable future. You, as an individual can never be using more than one at a time so, other than the one tool, the only other loads active simultaneously will be the potential DC and maybe a compressor.

Circuits for electric heat, etc., should, of course, be separate.

The "non fused disconnect" at each tool is, in ordinary terms, the plug on the end of the power cord.

--

[Dave In Texas]

When I wired my garshop I did two separate 240v circuits; one runs the dust collector and the other the table saw and a 5hp compressor (neither of which ever runs congruently). How often do you run more than one device at a time? Additionally, I ran four 120v circuits, two for power tools with each wall having a mix of both circuits and a single circuit each for the freezer and a "beer box."

Dave in Houston

[Swingman]

There may be one advantage (albeit slight) to wiring a "dedicated circuit" for a stationary tool, particularly in shops in "garages" ... a "dedicated circuit" is exempt from being GFCI protected in many locales.

At one time in the early days of GFCI, it was worth doing so as to not have to deal with nuisance trips, which are no longer the problem they once were.

[Robatoy]

Proper beer boxes are 550-V 3-phase, no?