# Help with shop electrical layout



## Hoakie (May 8, 2007)

Earlier this year we had some work done on our deck and added some lighting that required us to run electric outside. Since our main distribution box was buried in the finished portion of the basement, I decided to have them run a 40 amp sub-panel into my workshop. I didn't go over the top because I am not planning on staying in this house for ever and the price was right. The electrician left 4×20Amp breakers for me to use to wire up the shop so the question I pose to you is how best to distribute the power around the shop.

Just a couple of notes thing to consider

I already have all the shop lighting and some 15A outlets drops on the shop ceiling above the workbench that I can plug in routers, circular saws, etc. so I don't have to worry about that. 
Aside from low draw lighting and fan outside, this sub panel will only need to service the shop area.
There walls/ceiling are currently only framed in so I don't have to worry about running wire
I have a one man shop that rarely has more than one piece of heavy equipment running simultaneously except for the DC.
All of my tools are currently wired for 120. I don't plan on installing any 240 outlets since I don't think I'll need it in this shop
I think I would like to dedicate a circuit to the dust collector since it is on every time I fire up a major piece of equipment 
There are several places where I would like to run a double junction box so I have different circuits in close proximity (designated by two red circles close together)

So my questions for you guys are:


 Would you use all 4 circuits or would you do fewer (still leaves plenty of room in the box they installed)
 Do you see any benefit to alternating/staggering the circuits/outlets as much as possible? For example: put the band saw on Circuit 1, sanding stations on Circuit 2, router table/RAS on Circuit 2/3 double gang, and isolate DC on #4, etc to or is that overkill. 
What other things should I consider?

LEGEND:

SUB PANEL is between band saw and table saw
RED DOTS = proposed outlet locations


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## Manitario (Jul 4, 2010)

In reality, you're only going to be using one tool at a time, so running a bunch of different circuits for different tools will just waste wire. As well, if you are planning to use a few different tools at once, depending on the amp draw of your DC, you'll be close to maxing out the capacity of your sub-panel; eg. my TS is a 1.75HP which draws 17 amps; my DC was a standard 1.5 HP canister which drew 15 amps; leaves only 8 amps "free".


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## TopamaxSurvivor (May 2, 2008)

Just dedicate the DC, then alternate the outlets. 2 circuits should be plenty for you under those circumstances.


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## Hoakie (May 8, 2007)

Thanks guys. I was having similar thoughts that you all brought up but now they are at validated


I will dedicate the DC 
Run alternating circuits. Alternatively, I think I may double gang each spot, with one circuit/outlet pair because the cost to do it now is cheap compared later (time/effort)
*There will be at least one outlet within easy reaching distance of every major tool
Even though this is the basement I could eventually add more outlets in the garage which starts behind the drill press


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## HerbC (Jul 28, 2010)

Please note that the National Electrical Code requires GFI protection for outlets located in garages.


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## HorizontalMike (Jun 3, 2010)

Herb,
As best that I can find, NOT all garages have to have GFCI protection (though it is a good idea).

As I understand, GFCI is not required "IF" the garage is stand alone with a single electrical power source, has no water line, or other electrical conducting connection to the house's main power supply (that could include telephone lines, security wires for cameras, metal roofing, and cable TV).

If I am incorrect on this then please point me to the appropriate code(s). And what about older buildings and homes?


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## Hoakie (May 8, 2007)

I do plan on GFCI protection on each series of outlets


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## Belg1960 (Jan 3, 2010)

PLz, use boxes that are large enough for the 12/3 rx to go in and out plus don't forget that the devices need space as well. Are you planning on sheetrocking the walls after the electric is in? If you need help calculating the size of the box just ask. In your sitiuation you'll need to allow for 11 #12 conductors in any box with two wires and 2 recp, I would oversize it at least by one. I would use a 4" sqaure by 2 1/8 deep. http://www.munroelectric.com/silvereclipse/index.jsp?path=product&part=549&ds=dept&process=search&ID=,Boxes...Covers,Metal.Boxes...Covers,Misc..Boxes...Accessories,Box.Accessories Also do yourself a favor and add a stand-off support on them so when you plug things in and out the box won't flex.
http://www.munroelectric.com/silvereclipse/index.jsp?path=product&part=549&ds=dept&process=search&ID=,Boxes...Covers,Metal.Boxes...Covers,Misc..Boxes...Accessories,Box.Accessories


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## Hoakie (May 8, 2007)

@Bleg

Are you saying to use 12/3 to carry two different circuits to the dual junction boxes? I guess I hadn't considered that I figured I just run each on their own 12/2.

I guess I'm not sure I understand what you are trying to get at by saying allow for "11 #12 conductors in any box with two wires and 2 recp" are you saying there should be 11 places for the romex to come in the back?

I like the idea of the standoff but can you repost the link to the box? you duplicated the standoff link

Thanks


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## TopamaxSurvivor (May 2, 2008)

You cannot use a common neutral; ie, 12/3 on 2 GFCI protected circuits. You will need 12/2 on each circuit or 12/2/2 (2 sets of 12/2 with a ground). Also, the code now requires all 120 volt circuits to have its own neutral or use a multi-pole breaker if they share a neutral; ie, 2 pole 20 in this case using 2 120 volt circuits on 12/3.


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## Hoakie (May 8, 2007)

Thanks Topamax…that is what I figured and was/am planning on doing. I have a bunch of 12/2 wiring already so that isn't an issue.

Also forgot answer one of Belg's question…. I am planning on putting up sheeting when electric is in. I was probably going to use OSB instead of sheet rock because I think it would be too easy to accidentally punch holes in the drywall.


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## HerbC (Jul 28, 2010)

HorizontalMike,

Sorry, I was speaking in generalizations, I believe you're correct in the specific exceptions you noted.

On the other hand, I believe that new circuits in an existing attached garage would require gfi…

All these changes, that's why I got out of the electrical trade and into something really stable (computer networking and support)...

Herb


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## TopamaxSurvivor (May 2, 2008)

Herb, the NEC only changes every 3 years, not every day like networking ;-))


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## HorizontalMike (Jun 3, 2010)

Topa,
Yabut, to us old geezers it seems like every 3 months!

*;-)*


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## Belg1960 (Jan 3, 2010)

Yes, you can run 12/3 to the first box and have a GFI recp on each circuit within that box. This will be much cheaper than buying 2 GFI circuit breakers. You would then have to run 12/2 to each recp downstream of this first box. I would do it this way just in case you need to run 2 machine at the same time in the same small area. As per the code boxfill rules(how many wires you can have in each box) is calculated by adding together the number of wires, red white and black all grounds count as 1, every recp counts as 2, and I forget to add 1 counted for the clip holding the wires in place.
http://www.hardwareandtools.com/Hubbell-8240-Raco-4-Inch-Square-Steel-Box-2-1-8-Inch-Deep-6228613.html and then you need to use one of these but use the thickness of your wall covering http://www.ronshomeandhardware.com/8769-4-SQ-5-8-Box-Cover-p/881224.htm


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## TopamaxSurvivor (May 2, 2008)

If you run 12/3 from the panel, you will have to use a double pole 20 amp breaker, You cannot have 2 individually protected circuits on the same neutral.


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## Belg1960 (Jan 3, 2010)

You can run these on single pole breakers. You are thinking of the rule that says you must splice neutrals together if you run two circuits from one wire but if your using the two GFIs to create independent circuits you have met the same requirement.


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## TopamaxSurvivor (May 2, 2008)

Not quite sure what you are talking about there. You never tie the neutrals together after they leave the panel.

2 , maybe 3 code changes ago, the requirement was put in that all multi-wire circuits sharing a common neutral will disconnect all the hots simultaneously. Every hot leaving the panel goes with its own neutral or you use mutli-pole breakers for every set of circuits sharing the common neutral; ie, 2 pole or 3 pole as necessary.


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## Grandpa (Jan 28, 2011)

Horizontal Mike, I have a code check book that says GFCI is required in all garages and unfinished basements: Exceptions: recepts no readily accessible, single recept for equipment not easily moved (freezer) or duplex recept for 2 fixed appliances - 1999[210-8a3]. To me that says we need them in garages. This is a quick code check book but it references the NEC code book. In my state we grandfather homes until they are remodeled then the upgrade must occur. Not sure that is the safest thing but who can change their wiring every year? I used them in my shop and I have had no problems and am glad I spent the little extra to do it.


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## TopamaxSurvivor (May 2, 2008)

Last freezer outlet I installed here is WA, the state made me GFCI it!! ;-(( BEst case I can make for low temp freezer alarms!!


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## Grandpa (Jan 28, 2011)

I would think so. In Oklahoma they are still installing all GFCI in the garages except one for the freezer. This is a new home with an attached garage. They are using all GFCI on the kitchen counters, in the bathrooms (all recept) outdoors and around pools and spas. Why can't you develope an ARC breaker and a GFCI breaker to be used for a main. one breaker does it all. Then you could step down on the smaller circuits and still be protected. You need to work on that. You could be rich and good looking instead of just good looking. Well, that is what they say anyway =) Have a good day.


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## HorizontalMike (Jun 3, 2010)

I was thinking about using a CH 50amp GFCI breaker at the 200amp house main that feeds the garage/shop 125amp GE box, but discovered that the Cutler Hammer 50amp GFCI breaker clearly states "copper wire only" and I had used 2/0 Aluminum feed from the main to the garage/shop. I am assuming that there would be a problem with electrolysis concerning that possible solution. Oh well. *UPDATE-now I am NOT finding that copper wire specification... So which is it? *

Now I am looking at selectively adding some 120v GFCI outlets around the shop and upgrading my outlets in the house (kitchen and bathrooms). Not sure how to protect my 240v outlets (have 4) as I don't have room in my current GE 125amp box.


The house dates to mid-90s (bought it in 2000) and the garage I built in 2002.


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## TopamaxSurvivor (May 2, 2008)

The code clearly has required GFCI protection for garage & outdoor since the late 70s. Kitchen and bath were added in early - mid 80s. Isn't anybody doing legal electrical work in Texas? ;-))

Most breakers are rated Al/Cu. I would be very surprised if CH had Cu only on their breaker. They may on smaller sizes below amperages Al is normally used, but I haven't thought about it or check them.


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## HorizontalMike (Jun 3, 2010)

Topa,
Thanks on the Al/Cu thing, that makes me feel better.
So do you think this 50amp critter will handle my needs at the MAIN service box? Currently have a 100amp breaker there.

I run:
Lighting-when in the shop
8 double 8ft T-12s 
3 300w Halogen

1500w heater in winter
33gal. compressor (rarely kicks on)

And then ONE of the following 240v tools
3hp TS
BS
8in jointer

OR, would I be better off trying to crowd 4 #10 wires into one of these on my GE Load Center? I would only be using ONE at any point in time. Would 4 #10 wires even fit?


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## TopamaxSurvivor (May 2, 2008)

If the TS is runnng plus light and heat when the compressor kicks on, it might be marginal with 50 amp. I'm not sure what yoiu are dong with the 20 amp GE. Why not just use the outlet kind in the outlet boxes? Lot cheaper.


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## HorizontalMike (Jun 3, 2010)

I was thinking of doing the outlet thing for the 120v. However, I have four 240v outlets to deal with and am wondering how best to deal with them and thought about using the double pole 20amp GE GFCI in the garage load panel for my 240v load, that is IF I can get four #10 hot leads to fit (my other choice at HD is to go with 50amp GE.

If I leave the 100amp feed breaker in the main box and only change things in the garage/shop, I can combine and eliminate some of my 120v single pole breakers. Currently I have 3 double pole breakers in the load center for 240v(one feeds two 240v outlets and two others single dedicated). That double pole 20amp GE takes up 4 half slots (or 2 whole at of only 6 whole slots available).

I guess the bottom line is figuring out the best (most cost effective) combination to cover BOTH 120v and 240v service w/GFCI since I am working on a concrete floor.


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## TopamaxSurvivor (May 2, 2008)

You are not required to GFCI protect 240 volt equipment. If you want to, I believe you can get a faceless GFCI 240 volt rates that will go into an outlet box about the same cost as a 120 v. Lot less than the breakers.


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## yrob (May 26, 2008)

All that technical talk and subtleties about the electrical code that you guys are talking about (I guess some of you are licensed electricians) definitely convinced me that I am going to hire an electrician to do my shop.

Perhaps I can save money installing boxes and running the wires if I first get the electrician in there to spec it out and tell me what to do.

Unlike the original poster, the building I want to make into my shop (a barn) has no subpanel, just a couple lights and a couple outlets. So it needs the works..


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## TopamaxSurvivor (May 2, 2008)

Yup yrob, I'm the real deal ;-)) Passed my apprenticeship test long before licensing laws existed.


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## HorizontalMike (Jun 3, 2010)

I WAS a "sparky" ~40yr ago in the Navy. Since then I remember enough to stay out of trouble but sure have NOT followed all the changes in the NEC. *THAT's* why I ask Topa! *;-)*


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## exelectrician (Oct 3, 2011)

Topamax has nailed it got all the answers to all the questions. I absolutly agree with all his good advice. Now youall unzip the velcro on yore butt and go make sawdust!


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