# Feedback on your electrical capacity/layout



## Knot_Board_At_Awl (Oct 14, 2011)

I have a 21' x 21' workshop that I will be working on over the next few months (see My Workshop). As part of the preparation, I will be wiring up the shop to power all the great tools and gadgets. I plan on using EMT conduit for all the outlets and switches and to all the light fixtures so that any changes are relatively easy to do.

At this point, I plan on the following:

One circuit for the lights with two separate switched banks (front/back)
One circuit for the compressor and one for the future dust collector
Two circuits for 120V with two 4-outlet banks on each wall
Two circuits for 220V with 2 outlets on opposing walls
One outlet in the middle of the room along the beam on the ceiling so while working with power tools, I won't need any dreaded extension cables!

I was hoping to get some feedback from some seasoned workshop people out there as to what has worked for them and what they wished they did differently.

Thanks!
Mike


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## TopamaxSurvivor (May 2, 2008)

If you are primarily working alone, that should easily cover the electrical load.


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## jusfine (May 22, 2010)

Mike, I had access to duplex receptacles from renovations in office buildings, so I put one duplex every 5' all around the perimeter of my shop about 12" off the floor plus a few more at 4' off the floor near my benches or tables, a couple more in the ceiling for cables as you mention, as well as wired two for air cleaners which mount to the ceiling.

My shop is built in the loft of my barn, and I have access to a 100 amp panel, so I put quite a few 220 connections in for larger machines, I think I have 6.

As Topa mentioned, you look like you have it covered. I might put a few more duplex receptacles in around the shop, it's so handy to have them close and not have to drag cords out and have them lying on the floor.

All the Best!


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## Finn (May 26, 2010)

I also put conduit and duplex outlets all around my shop but when building a shop just like mine for a friend I put in all 4 plex outlets instead. Wish I had done that in my shop.


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## brtech (May 26, 2010)

A small idea: Run both circuits to all the quad boxes. Put one duplex on each. Make one ivory and the other brown and keep ivory on circuit 1 on the left, brown on circuit 2 on the right. Makes it real easy to spread the load if you need to worry about it.

Also, if you are like many of us, you have a bunch of chargers, some of which have "wall warts" for portable power tools. I find mounting one of those longer spaced multioutlet strips near a shelf is real handy. I also like to put a switch on that strip if it doesn't have one because if I'm not charging anything, I like turning the chargers off.

Also, you might get one of the spring loaded reel extension cords to put up next to your ceiling mount outlet.


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## kizerpea (Dec 2, 2011)

mike…my shop started 24 by 24 now 24 by 46…think of future add on i have drops from the ceiling that hang just above my head . keeps the need for drop cords at a min…. my wall plugins era 3ft apart 4 fr off the floor. i dont want to bend down behind stuff to get to a plug…


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## TopamaxSurvivor (May 2, 2008)

I put them on every other stud along my work bench.


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## Bluepine38 (Dec 14, 2009)

I second Topomax on the one duplex every 32"-every other stud- then run every other outlet on the same
circuit, a buddy used 12-3 w/ground and breaking the strap on the live wire side of the outlet ran each half
of every outlet on a different circuit just to make sure no outlet was ever overloaded. It only takes a few
cents for each outlet compared to the hassle of not having enough outlets, or tripping breakers by overloading
an outlet, but I am a persnickety old fart.


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## TopamaxSurvivor (May 2, 2008)

The City of Seattle used to require breaking that tab and putting 2 circuits on kitchen appliance outlets. UL says that is 240 volts on a 120 volt rated device. The city had to stop that practice.


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## Knot_Board_At_Awl (Oct 14, 2011)

Some good suggestions.

I was planning on wiring two circuits to each 4-outlet box - each duplex on its own circuit in order to share the load for the "popular" outlets. Due to derating factor from multiple conductors in the conduit, in order to get 15A I need 10AWG for each circuit. The funny thing is the 10AWG with the derating will also allow 21A so I will be running 20A circuits to everything. I'll throw a few more in as suggested. You can never have too many!

For the workbench, and as suggested by brtech, I was thinking of using a couple of 4 foot power bars so that wall-warts don't consume extra outlets like they do on duplex outlets. That way I can also keep my chargers plugged and ready to go and still have other outlets available. I like the idea of a switch to turn it off when not needed. Good idea!

I think the Canadian Electrical Code still allows two circuits on one duplex with the tab removed. When the kitchen is renovated, I think I will alternate outlets/circuits instead of splitting them and for the shop, the four-plex with two circuits should help prevent any overloads.

Thanks everyone for the great tips. Some more stuff to think about and more items to add to the plan. I'll be sure to add some pics to my workshop once I get some stuff wired up.

Mike


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## Manitario (Jul 4, 2010)

sounds like a great setup, unless you plan to leave all your tools running at once.


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## TopamaxSurvivor (May 2, 2008)

How many wires are you putting in a conduit? #12 starts derating at 30 amps even though it is protected at 20. 9 current carrying conductors derates to 70%, which is still 21 amps for #12 THHN. I would definitely go with 20 amp circuits, not 15.


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## Knot_Board_At_Awl (Oct 14, 2011)

I will be running 20A circuits, but here's how I came about requiring 10AWG: (BTW, THHN is not available for use up here in Canada. We have to use R/RW/T 90 wire)

According to the CEC-2009 Table 2 (Allowable ampacities for not more than three copper conductors in a raceway) and based on T90 wire and a 30C ambient:

14AWG: 15A
12AWG: 20A
10AWG: 30A

Derate as follows:

1-3 conductors: 1.0
4-6 conductors: 0.8
7-24 conductors: 0.7

so now:

14AWG: 10.5A
12AWG: 14A
10AWG: 21A

Now unless I've missed something, I'll have to run 10AWG wires for all my 20A. In addition, any 15A circuits (lights) will need 10AWG as well.

Mike


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## Bertha (Jan 10, 2011)

I might consider a few more 220's. I had four installed and I'm already running equipment at 110 b/c I ran out of outlets. There has been plenty of debate here about running 110 v 220 but my equipment runs totally different on 220. Good luck!


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## TopamaxSurvivor (May 2, 2008)

That is nearly unbelievable! Oh well, guess CU stocks are looking good before you start the job ;-))


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## NBeener (Sep 16, 2009)

I put my wall outlets at about 55" from the floor, leaving enough room to have 4×8 sheets (on their sides, obviously) below them, without interfering.

Second the notion of two circuits per 4-plex outlet


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## Knot_Board_At_Awl (Oct 14, 2011)

I just read something interesting. Apparently the 2012 Canadian Electrical Code will align conductor ampacities to those of the NEC. Hopefully this will reduce the 10AWG requirement to 12AWG for all my 20A branch circuits and save a few bucks since copper is so expen$ive.

Now I just need to wait until the 2012 CEC is adopted by the provincial governments which probably won't be until September for BC


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## TimmyP (Sep 13, 2011)

Mike, I'm glad I found your postings here (along with everyone else's), as my shop is about 20×20, and I want to put some outlets in the shop, instead of having to run an extension cord everytime I use my power tools. I'm thinking of just 2 new 15A circuits, and 1 20A circuit, should cover most of my needs (plus future needs). (everything running on 120V, no 240 stuff). Like you, I'm thinking of putting some drop-down outlets in, just because of where I plan to put the bench and stuff. I think what would really be cool, is to put the outlets in the floor, that way the big power tools (tablesaw, jointer, bandsaw) could plug right into the floor, and the cord would be out of the way for any oversized stock. Of course, to do that, I'd have to figure a way to either remove or lift off the laminate floor, put in subflooring, and run the outlets, then put the laminate flooring back down. Fat chance all that will happen!!

Good luck, hope to hear how things turn out.

Tim


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