How many electrical outlets per shop circuit?

[Travis]

In general, does anyone know how many electrical outlets one would place on a shop circuit. I am already assuming that it wouold be best to use 12 AWG wire for the outlets and that I should keep the lights on a seperate circuit.

Thanks for any input.

 

[woodguy1975]

In general, does anyone know how many electrical outlets one would place on a shop circuit. I am already assuming that it wouold be best to use 12 AWG wire for the outlets and that I should keep the lights on a seperate circuit.

Thanks for any input.

As many outlets as you want is fine for the most part as long as your total load isn't greater than your wire/breaker limit. I think I have 10 at least outlets per circuit. Put your lights on their own circuit too. If you blow you won't blow in the dark.

You'll want to run as many 220V outlets as you do 110V for the most part. I have 2 220 circuits in my shop that are shared among tools and one dedicated for the dust collector. You can really get away with a single 220V circuit for the tools and another for the collector. As long as you don't start them at the same time you'll be able to run multiple tools no problem.

Thanks,

John

 

[toolferone]

I think I have about 5 per circuit. One though is to daisy chain the outlets, that way outlets next to each other will be on different circuits.

 

[froglips]

Bottom line, no "code" requirement for a maximum.

The thing to keep in mind is added resistence. But if you have more than 10 outlets on one circuit, you might want to reexamine your plan....

I have 16 x 20amp outlets, 8 per circuit. Also ran one 15amp circuit for lights and small things.

BTW, if you can, make sure the first outlet on the run is a GFCI, or use a GFCI circuit breaker.

We won't go into how my extention cord fell into the bucket of water, but I'm a big fan of GFCI.....

Jim

What is the maximum number of 15 or 20A, 125V receptacle outlets permitted on a 20A, 120V general-purpose branch circuit in a commercial occupancy?

A1 For commercial occupancies, the NEC requires each receptacle outlet to be calculated at 180 VA [220.14(I)]. Therefore, the maximum number on a 20A circuit would be 13.

Circuit VA = Volts x Amperes
Circuit VA = 120V x 20A
Circuit VA = 2,400 VA
Number of Receptacles = 2,400 VA/180 VA
Number of Receptacles = 13

Note: According to the NEC Handbook, published by the NFPA, general-purpose receptacles aren't considered a continuous load.

Q2 What is the maximum number of 15 or 20A, 125V receptacle and lighting outlets permitted on a 15A, 120V general-purpose branch circuit in a dwelling unit?

A2 The NEC doesn't limit the number of receptacle and lighting outlets on a general-purpose branch circuit in a dwelling unit. See the NFPA's NEC Handbook for more information.

Although there's no limit on the number of lighting and/or receptacle outlets on dwelling general-purpose branch circuits, the NEC does require a minimum number of circuits to be installed for general-purpose receptacles and lighting outlets [210.11(A)]. In addition, the receptacle and lighting loads must be evenly distributed among the required circuits [210.11(B)].

Caution: Not likely, but there might be a local electrical requirement that limits the number of receptacles and lighting outlets on a general-purpose branch circuit.

 

[wapitiscat]

You could also think on terms of "zones". Foe example, as mentioned already, a ceiling light zone, east wall zone, overhead zone, etc. My garag ... I mean workshop was wired when I bought the house and the guy has GFCI outlets in addition to non-GFCI. I'm not sure what his motivation was but I do know that the primary (if not sole) purpose of the garage was to shelter his bass boat. Maybe he was going to have a small bass pond inside for testing the latest lures. I will use the GFCI curcuits when I put an exterior outlet on the back of the shop so maybe that was the thinking (I like the bass pond explanation better). To paraphrase Ben Franklin ... the sting of having to run an extension cord lasts longer than the pain of wiring a few "extra" receptacles. Anyhow, good luck with the wiring.

Todd

 

[yellofins]

My set up is a lot like Tom's. I have 5 double outlets on surface mounted boxes per 20A feed.
Every other outlet is on the same circuit so I do not have 2 outlets next to each other on the same breaker. I color coded the outlets (Grey and White outlets) so I can easily identify which circuit I'm on.
I have an isolated run for Dust Collection (right now it's only used by a shop vac).
Ron

 

[McRabbet]

Travis,

I want to add to the comments made by Woodguy and Froglips. I've added a diagram of my shop wiring done more than a year ago.
(Click on thumbnail for full-sized image)
Since you are using 12 AWG wire, be sure to use 20-Amp industrial quality duplex receptacles. Note I added a GFCI outlet closest to the panel on Circuit 1 (numbered end of my circuits "home run" to the panel) because my dust collector is in my crawl space, which is technically "outside". That circuit has 9 receptacles, including 3 double boxes with 2 receptacles. Lighting is 14 AWG in 3 circuits, with 3-way switches at each entry. I used 4-bulb T-8 Troffers from the BORG at about $45 each with bulbs and a 6-foot whip on each for easier wiring -- plenty of light! I installed all the wiring and breakers and have never had a breaker pop.

Note to Todd regarding the garage mixed GFCI/non-GFCI receptacles: By most local codes, GFCI is required as they assume you'll plug in your outside garden tools or Santa display into it, so it is an "outside" circuit.

You need to test your non-GFCI outlets. How? Push "test" on one GFCI receptacle and see if the standard outlets are still hot. If not, mark the ones for that circuit and reset the GFCI. Do this for each GFCI. If no standard outlets go offline, then they are not on those GFCI's and you need to add same. 2 choices: Add a GFCI breaker at the panel for each circuit (expensive choice), or replace the 1st receptacle (closest to panel "home run") with a GFCI receptacle and slave the remaining outlets on that circuit (instructions in GFCI receptacle you buy). Repeat for each circuit.

Rob

 

[wapitiscat]

Thanks for the clarification Rob. I guess I was stumbling to that conclusion as I was going to tie into a GFCI circuit for a bona fide outside receptacle. Does the same hold true for an outside switch? I was going to extend an existing 220 circuit (dust collector) to an outside single pole switch to power a well pump that will see intermittent use (e.g., not when I'm running the DC). Do I need to include a GFCI in this circuit? If so, I'll probably switch the pump to 110 and tie into one of the aforementioned GFCI circuits. Sorry if this diverges too much from the original post but I gots ta know.

Todd

 

[D L Ames]

Does the same hold true for an outside switch? I was going to extend an existing 220 circuit (dust collector) to an outside single pole switch to power a well pump that will see intermittent use (e.g., not when I'm running the DC). Do I need to include a GFCI in this circuit?

Todd

Todd, that is an interesting question. I used a switch on one of my 220 circuits that my compressor is tied into. Neither it or any of my other 220 circuits are GFCI protected.

D L

 

[junquecol]

NC used to require the recepticals closest to doors to be GFIC.
Use #12 wire and 20 amp recepeticles. They can be "back wired" by tightening screws. Special green wire nuts are handy. If using metal pipe, use 3/4" stuff. Oct. 2005 Popular Woodworking had a good article on "Efficent Shop Wiring" using duplex breaker to supply both one 220V and two 110V circuits, using two hots, neutral and ground. Think about it-Seldom do you run more than one machine at the time. Aug. 2000 FWW had an article about mounting a sensor in panel to control DC. I added a cube timer to allow DC to run on for ten seconds to clear pipes-SWEET!

 

[McRabbet]

Thanks for the clarification Rob. I guess I was stumbling to that conclusion as I was going to tie into a GFCI circuit for a bona fide outside receptacle. Does the same hold true for an outside switch? I was going to extend an existing 220 circuit (dust collector) to an outside single pole switch to power a well pump that will see intermittent use (e.g., not when I'm running the DC). Do I need to include a GFCI in this circuit? If so, I'll probably switch the pump to 110 and tie into one of the aforementioned GFCI circuits. Sorry if this diverges too much from the original post but I gots ta know.

Todd

I'm not qualified to answer that one fully (you do need a weatherproof switch enclosure) -- you've stumped this swami! I suspect Ozzie-x could answer it for you -- send him a PM with the details. Rob

 

[Travis]

Thanks for all of the terriffic responses. You guys have exceeded my expectations once again. I will now wire the shop with confidance.:icon_thum

 

[chris99z71]

On a somewhat related topic...
I know that garage circuits are required to be gfci, but are basement circuits required to be gfci?
Also, is there much advantage to using a gfci breaker vs just making the first recepticle a gfci?

 

[sapwood]

Chris, though I lack electrical expertise I can related personal experience :-D

GFCI breakers are surprisingly expensive. GFCI outlets are "moderately" priced. I've had few problems with GFCI outlets, but I've had many problems with GFCI breakers :BangHead::BangHead: Two of three brand new breakers proved defective (had to pay an electrician to diagnose as I figured it was something I had done wrong :-(). The 220v GFCI breaker for pool pump has "phantom" resets. Does fine for three weeks, then flips 3-4 times in one day. I had it checked out by a competent electrician who remains baffled. :roll:

Roger

 

[NCPete]

Travis, just found this on HF, maybe going there to pick a few things for my shop, including outlets! http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91541

 

[Travis]

I live in Hiclory but hear there is a harbor freight in Raleigh. I will have to check it out the next trip visiting family.

 

[McRabbet]

Travis, I would buy good quality receptacles, especially when it comes to GFCI ones. Never skimp when safety is first. The dollar difference is not all that much, so why take a chance? Just my .02

Rob