# New Workshop Electrical Question



## mprzybylski (Nov 21, 2011)

Hello everyone,
Let me preface what I'm about to type by saying I'm a complete electrical newbie and have been trying to learn for the past few weeks in preparation of wiring for my new workshop (3 car tandem garage). I am moving into a new construction home and want to add a bunch of 220 and 110 outlets with surface mounted conduit. I'm trying to figure out if I have the wiring correct as I want a single 20A, 220V receptacle and a duplex 20A, 110V receptacle in each box.

The attached image is of the first run coming out of the panel. My plan is to have a breaker for the 220 and a separate breaker for the 110 in the panel. I want to run all the 220 outlets on one circuit and the 110 on the other in this particular line (there is about 3 of these in different parts of the shop, all on their own dedicated circuits). This run will have 4 boxes (3 of which you see here, one more not pictured but the same as the right two setups continued down the line). I want to make sure that I have the wiring correct as this is the basis for the other two runs as well which would mimic this run but on the opposite wall as well as one on the ceiling.

Could someone much more intelligent than I when it comes to electrical work please let me know if this is wired up correctly or if I'm completely off base? I really appreciate the help as this is nerve wracking for me and I've been trying to figure out how to do it for the past few weeks in my head so I wanted to get something down "on paper".

I'd also like to know if I need to ground each receptacle in the box? If so, how would that work with one grounding screw in the box and two separate receptacles? Would I just add one more ground wire to each wire nut and run them both (one from the 220 and one from the 110 receptacle) to the one ground screw on the box together?

And yes, I know I can hire an electrician to do this but I won't because 1) there is a lot of work to do on this and it will get expensive very fast, 2) I want to (and feel like I need to) learn how to do this myself in case of future expansion and 3) I am already going to be shelling out a bunch of money for furniture, back yard, etc, so I'd like to save here where I feel like I can actually do this myself (hah!).

The image is showing up really small so here is a link to Dropbox with a larger version: https://www.dropbox.com/s/lz2r9d55grt3fcm/wiring-plan-long-wall.jpg?dl=0


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## onoitsmatt (Mar 7, 2015)

I can't help you Matt. But welcome to Arizona! If possible get a minisplit in there. That shop will be useless 3 months out of the year without one.


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## JBrow (Nov 18, 2015)

Matt Przybylski,

I personally would not place 240v and 120v receptacles in the same box. I would rather keep the differing voltages completely separate in separate boxes. I am, however, not sure that this is an electric code requirement.

When confronted with the problem of multiple equipment grounding conductors that must be connected to a single device, I use a wire nut (although copper barrel connectors could be used) to connect the bare copper equipment grounding conductors along with a 6" - 8" piece of bare copper to form a "pigtail". The 6"-8"length of bare copper that constitutes the "pigtail" is connected to the device (i.e. receptacle) at one end at to the other end to the bare copper conductors.

If the copper barrel connector is used, one conductor in the circuits can be left long enough to connect to the device and the barrel clamp used to bond the other bare shorter copper conductors to the left-long conductor. If there are two separate circuits in the same box, I like to keep the bare equipment grounding conductors aligned with its own circuits (even though back at the service entrance panel, the circuits are bonded).

If the receptacle box is metal then a bare copper equipment grounding conductor must be connected to the metal box and wired into the circuit's equipment grounding circuit. Since plastic boxes are non-conductive, then no bonding of the plastic box is needed. It is for this reason that I prefer non-metallic boxes. But the device (e.g. receptacle) must be connected to the equipment grounding circuit.

I applaud your do-it-yourself attitude. Messing around with electricity, though, is not something that should be done by someone that has no clue. There are fire codes (incorporated in the National Electric Code) that could come into play should a fire or injury result. The insurance company could refuse to pay a claim if the NEC was not followed. A passed electrical inspection is the best insurance for a do-it-yourselfer. On these believes, I recommend educating yourself regarding electrical wiring and then ensuring your work is inspected by the county inspector. These inspections seem prudent to me should a fire or personal injury ever result; proof that the electrical work was done per code. In my experience in multiple jurisdictions, electrical inspectors are the do-it-yourselfer's friend especially if you seem to know what you are doing.

You could read the National Electrical Code to educate yourself, but, having done so, I found this very laborious and mostly confusing since I am not a pro. The best resource I have found is "Wiring Simplified". It is far better than any other book I have looked through and recommend it to you.

https://www.amazon.com/Wiring-Simplified-Based-National-Electrical/dp/099790531X


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## mprzybylski (Nov 21, 2011)

JBrow, thank you for the response. I should have mentioned that I'm only running all of the conduit/wires in the conduit/boxes/leg work myself and am going to have an electrician come in and look everything over and do the connection to the panel. What I drew up here was what I thought I understood the electrician who came to give me an estimate (who was very nice and walked me through how I should wire it, although its kind of in one ear out the other type of thing until you sit down and experience it) said. I'm just verifying that I understood him correctly and hoping someone can clue me in if I made any mistakes.

I'm also sending this information to him as well as another neighbor who is an electrician back in Chicago, but I'm just looking to get as much input as possible from everyone I can. As you said, I don't want to violate any codes.

Getting in touch with the city's electrical inspector is a great idea that I did not consider. I can probably draw everything up, take it over to them, and hopefully they can give me some insight as to if I'm doing it right. Thanks for that tip!


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## TheFridge (May 1, 2014)

There isn't any code I know that won't allow the receptacles in the same box. Temporary power poles and generators do it.

The 20A 250V receptacles can't be wired like that. Must be dedicated if another electrician is gonna put his name on it. Any 250V receptacle must be dedicated unless the feeder is size appropriately which just opens another can of worms and tap rules and whatnot.

No more than 10 receptacles on a 20A circuit.

In your garage or shop, all of your 15 or 20A receptacles must be GFCI protected. Putting a gfci receptacle at the start of the circuit and putting everything on the load side is the cheapest. Gfci breakers aren't cheap.

Strap your pipe at least every 10' and within 3' of every box or accessible fitting.

Gotta have at least 6" of wire out the pipe or 2-3"? out of the box. Whichever is greater.

If any wire is spliced in a box then the box has to be grounded.

If you use stranded wire you don't strip right at the end. You strip a 1/2" or so window about 2" from the end of the wire. It keep the end of the wire from fraying and keeps it insulated when tightening the terminal if landing on screws.

Rule of thumb- 9- #12s in a 1/2" and 16- #12s in a 3/4" pipe.

This is the basics an electrician will look for and by no means covers everything.


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## mprzybylski (Nov 21, 2011)

TheFridge, thank you for your input.

When you say they can't be wired like that, why not? I will never use two machines at once on one 220 run.

As for 10 receptacles on a 20A circuit, is a duplex receptacle counted as two receptacles or one?


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## TheFridge (May 1, 2014)

But there is the possibility as far as code is concerned. Unless there is a control circuit that would lock the other out you can't do it. My table saw and jointer is on the same circuit in mine but I didn't need another electrician to look at it or an inspection.

One.


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## TopamaxSurvivor (May 2, 2008)

The 120 volt GFCI protected circuit needs to be in a separate conduit. GFCI and non GFCI circuits cannot be in the same conduit or enclousre.

Unless something changed in the last code update, you can have multiple 220 outlets on a circuit. I did it for a customer in an airplane hanger just before I retired. I don't have a new code book and don't want a new code book ;-) Another new code book is due out this year.


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## mprzybylski (Nov 21, 2011)

TopamaxSurvivor, I read this in multiple places: "GFI and non-GFI conductors can indeed occupy the same conduit or raceway. The restriction is only for underwater pool lights."


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## tyvekboy (Feb 24, 2010)

The only thing that I can add is that if you put multiple 220v outlets on one circuit, I wouldn't run more than ONE 220 device off of that circuit at the SAME time. I have one 220v circuit that has (2) 220v outlets but I only run ONE 220 motor on that circuit at a time. I don't know the code but I would rather have a separate circuit breaker for each 220v machine.

As far as the 20A - 120v duplex outlets I have quad outlets (4 in one box) spaced every 5-6 feet apart on the walls 42" from the floor. Every other quad outlet box is one one 20A circuit and the others are on another circuit. That way I can plug in many devices and they can be on different circuits depending on which outlet I plug them. I also put labels on my outlet boxes so I know which circuit breaker to which it is connected.

Another option someone suggested is to run multiple circuits and put outlets in one box on different circuits.

Another thing I did after I wired everything up I got a tester to check that the polarity was correct on each 120v outlet. The tester looks like:










I studded my shop and have plywood walls. Therefore I ran the romex behind the walls the mounted metal boxes on the walls where the romex came through a 1 inch hole. See my workshop tab for more details. If you don't want to use conduit, you could also cut out a 1 foot section of sheet rock starting at 36" above the floor and ending 48" above the floor. Then you can run your romex behind the sheetrock like I did and mount your outlets on the 1/2 inch plywood that would replace the sheetrock that you cut out. Attach the plywood with sheetrock screws in case you want to reposition the outlets.

Hope this helps.


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## MadMark (Jun 3, 2014)

Put your outlets over 48" up to prevent sheet goods from covering them.

M


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## TopamaxSurvivor (May 2, 2008)

> TopamaxSurvivor, I read this in multiple places: "GFI and non-GFI conductors can indeed occupy the same conduit or raceway. The restriction is only for underwater pool lights."
> 
> - Matt Przybylski


Is that in the 2014 NEC? The restriction was fairly new before I retired.

Edit: I just Goggled that. The statements that popped up appear to be 10 years old. I believe the universal restriction came in 2008 or 2011 code. Glad I'm retired ;-) ;-)

I would be quite surprised is they relaxed that requirement. The electrical code just gets more and more strict. Multiple circuits on a common neutral are not allowed any more without common disconnect and they have to be identified with their hot conductor at each j box. That is a bigger burden on commercial and industrial that typical residential methods.


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## wapakfred (Jul 29, 2011)

> Unless something changed in the last code update, *you can have multiple 220 outlets on a circuit*. I did it for a customer in an airplane hanger just before I retired. I don t have a new code book and don t want a new code book ;-) Another new code book is due out this year.
> 
> - TopamaxSurvivor


That's my understanding as well, and what I have done in my last 2 shops and the current one (which I'm wiring now). I won't have an inspection, but still try to stay to code. BTW, here's the wall plate for that240/120 configuration. You might want to bookmark it, they ain't all that easily found.


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## TajBuilder (Aug 6, 2008)

GFCI restrictions apply depending on whether the space is considered finished or unfinished and garages are generally considered unfinished space. What you are trying to do is run three strand wire to feed two circuits. This is commonly done on 120 volt outlets where a dishwasher and garbage disposal share the same box. In this instance there must be a bar that ties the two breakers together so that if one circuit trips the other will also trip and the entire box will be cold.

You can also use three strand wire to run 120v and 240v to the same box and even the same outlet. Leviton makes a combination outlet for this purpose. A 240v breaker controls both circuits and will render the box cold if either circuit causes it to trip.

https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwi5u9fsjsrSAhWUuMAKHXGKDNcYABALGgJpbQ&ohost=www.google.com&cid=CAESIeD2WrvdGjT0fElnof4P2ZVwqonO_2Hjy8zi_xxBPRUs4Q&sig=AOD64_1DL5QTvn9HW7VQj2bmfSnELn18Tw&ctype=5&q=&ved=0ahUKEwj9rNLsjsrSAhXn1IMKHY0OAasQvhcILg&adurl=

I ran 10/3 romex for my 240v circuits when I built my shop so I could run multiple machines at the same time. I routinely had three 1 hp wood lathes running at the same time without a problem. Two of the lathes also had 120v duplex outlets on them so I could run a right angle sander and lights while running the lathe. I used a 20 amp breaker because the cords and connections for some of my 240 v tools are only rated for 20 amps even though the 10 gauge wire is rated for up to 30 amps, The 10/3 wire is extra insurance that I won't have an overheating problem because it has less resistance than 12 gauge wire.

I pulled a permit when I built my shop in 1997 and did the wiring myself. Hope this helps.


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## WhyMe (Feb 15, 2014)

Your diagram is fine unless you have a local code prohibiting multiple 240V outlets on a single circuit. NEC doesn't restrict multiple 240V outlets on a single circuit, but the IRC does limit multiple 120V/240V outlets on one circuit to 20A outlets. And where someone said no more than 10 outlets on a circuit is just a rule of thumb and is not set by the NEC.


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## sawdustdad (Dec 23, 2015)

I wired my new shop about a year ago. I ran 10/3 w/ground to all the 240V outlets (12 outlets on 6 circuits) and installed 4 wire twist lock outlets in every box. Most boxes had 30A receptacles, one was 20A. I did not share any boxes with 120V. I then created adapter cables to go from the 4 wire twist lock outlet to the appropriate female plug for each machine. Since many of my outlets are in the ceiling, the twist locks keep them from coming loose.


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## pontic (Sep 25, 2016)

The fridge gives good advice. All 220 circuits need to be dedicated. That means on a separate breaker. You want multiple 220 outlets then get an secondary breaker box. Total up your amperage for the 220's and run appropriate wire to the box and 20amp breaker off each circuit. Add more current handeling to the wire if you want 120 to come off the same box. The way you have it wired all the 120 is coming off one leg. This will increase the impeadence on one of the poles of the 220 motor too much and cause the windings the heat up and shorten the life of the motor. Especailly if you have a heater circuit on the 120 somewhere.


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## wapakfred (Jul 29, 2011)

> The fridge gives good advice. All 220 circuits need to be dedicated.
> 
> - pontic


Not by the NEC, though what locals require is anybody's guess. In fact you can get 240V/20A duplex outlets if you want.


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## WhyMe (Feb 15, 2014)

> The fridge gives good advice. All 220 circuits need to be dedicated. *Not necessarly.
> *
> 
> The way you have it wired all the 120 is coming off one leg. This will increase the impeadence on one of the poles of the 220 motor too much and cause the windings the heat up and shorten the life of the motor. Especailly if you have a heater circuit on the 120 somewhere.
> ...


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## pontic (Sep 25, 2016)

Well I Have seen this happen in more than one Dental office. Grossly unbalanced loads burn up a few compressor motors.


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## TopamaxSurvivor (May 2, 2008)

> Unless something changed in the last code update, *you can have multiple 220 outlets on a circuit*. I did it for a customer in an airplane hanger just before I retired. I don t have a new code book and don t want a new code book ;-) Another new code book is due out this year.
> 
> - TopamaxSurvivor
> 
> ...


The criteria would be a general purpose circuit can have multiple 220 volt outlets. If you say it is dedicated for a purpose, then no additional outlets can be on the circuit.


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## WhyMe (Feb 15, 2014)

> The criteria would be a general purpose circuit can have multiple 220 volt outlets. If you say it is dedicated for a purpose, then no additional outlets can be on the circuit.
> 
> - TopamaxSurvivor


That statement is ambiguous. A general purpose circuit is multiple outlets. Saying it's a dedicated circuit doesn't prevent the addition of more outlets making it a general purpose circuit. The determining factor is the amp rating of the circuit. Under International Building Code a general purpose multiple outlet circuit can be no more than 20 amps for either 120V or 240V. Over 20 amps, circuits are to be dedicated, a single outlet.


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## TopamaxSurvivor (May 2, 2008)

Possibly and probably ambiguous to the layman I suppose. General purpose circuits provide power for convenience to connect anything of appropriate size. A dedicated circuit is to a specific piece of equipment. Your dedicated small appliances in a house such as the washer, dishwasher and disposal are dedicated circuits that do not allow additional outlets. The other circuits in the house are general purpose. Hope that clears the mud ;-) The same rules apply to larger circuits by NEC.


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## pontic (Sep 25, 2016)

I suppose I'm laboring under some misconceptions, This thread has been very informative, There are a lot of smart kats on this forum.


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## FarmerintheWoods (Mar 3, 2017)

Back in the day, code required #10 wire for 220v. 110v: #12 wire for up to 10 duplex outlets per circuit, #14 for up to 8 duplex outlets per circuit. Your local code will address this for sure, and it would be good to know before pulling wire.


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## mprzybylski (Nov 21, 2011)

Just wanted to do a follow up on this as I've slightly revised it. I'm thinking of running separate conduit and the box layout as specified in the image. The reason for splitting the conduit is that there would now be 2 110 wires in one conduit and the 220 wires in the other. I may run other wires for other things in some of these conduits as well (one set in the 220 conduit would go to a mini split AC system on a dedicated 30A circuit, I may run another set for an outlet I need to add on the other side of the garage wall for an electric fireplace, etc. Running multiple conduit would give me more flexibility in that I believe).

Is this an acceptable setup?

https://www.dropbox.com/s/y6pept6u7gtobst/wiring-plan-long-wall-conduit.jpg?dl=0


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## WhyMe (Feb 15, 2014)

Even though your picture has 20A 120V outlets I assume you are aware there is really no need for them. Multiple 15A 120A outlets are fine on a 20A circuit.


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## TopamaxSurvivor (May 2, 2008)

> Even though your picture has 20A 120V outlets I assume you are aware there is really no need for them. Multiple 15A 120A outlets are fine on a 20A circuit.
> 
> - WhyMe


I would use them as they are higher quality, better for plug and unplug cycles and less prone to breaking down with heavier loads. Cheapest is not necessarily best ;-)

Matt Przybylski, I assume that drawing shows you are running both conduits through all the boxes. If so, your wire fill in the boxes will be too high.


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## mprzybylski (Nov 21, 2011)

Bob, yes, that is how it is depicted and was my plan. My reasoning behind it is that I don't know how to otherwise do it. If I ran separate conduit to separate boxes, I'd have to vertically space everything an extra 4-6" and I think it would look a bit odd in that configuration. Is that normally what people do if they have different circuits but in the same positions with conduit?


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## AZWoody (Jan 18, 2015)

> Bob, yes, that is how it is depicted and was my plan. My reasoning behind it is that I don t know how to otherwise do it. If I ran separate conduit to separate boxes, I d have to vertically space everything an extra 4-6" and I think it would look a bit odd in that configuration. Is that normally what people do if they have different circuits but in the same positions with conduit?
> 
> - Matt Przybylski


I had to redo all the wiring in my shop and i had an electrician do it because there was insufficient wiring to the panel so they had to pull a lot of wiring. They used one main conduit for 3 or 4 different circuits and just ran multiple wires that are all different colors so they can then just differentiate the circuit as they were putting in the outlets.

I believe one wall had 2 -120 circuits and 2 - 220 circuits through one conduit with multiple boxes along the length.


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## mprzybylski (Nov 21, 2011)

That is good to know AZWoody, thanks for the input.


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## WhyMe (Feb 15, 2014)

> Even though your picture has 20A 120V outlets I assume you are aware there is really no need for them. Multiple 15A 120A outlets are fine on a 20A circuit.
> 
> - WhyMe
> 
> ...


This is a misnomer about being higher quality. If you get spec grade outlets the quality is the same for 15A vs. 20A. The added cost on the 20A outlet is for the extra contact for the sideways spade on a true 20A plug. The 15A outlets are rated for 20A pass through current just as the 20A outlet. So the 15A being cheaper is not about quality.


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## TopamaxSurvivor (May 2, 2008)

There is a lot of difference in the quality of outlets and switches. I never used spec grade and I told my customers why I didn't. But I wasn't dealing with the residential market either ;-)


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## WhyMe (Feb 15, 2014)

Be aware that pulling more than 3 current carrying conductors in a raceway will result in having to derate the wire's ampacity. http://www.southwire.com/support/DeratingAmpacities.htm


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## TopamaxSurvivor (May 2, 2008)

Matt, If you are piping for extra capacity in the future, you need to keep the fill in the boxes to a minimum. Having to run a neutral for every 120 circuit adds even more current carrying conductors to the count. You can use a multiple pole breaker instead of doubling up the neutrals, but when you trip a breaker you lose a both circuits. I refused to do that to my customers.

Running the conduits to separate boxes will require the boxes to be slightly offset or the conduit to be bent and run above or below.


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## TopamaxSurvivor (May 2, 2008)

> Be aware that pulling more than 3 current carrying conductors in a raceway will result in having to derate the wire s ampacity. http://www.southwire.com/support/DeratingAmpacities.htm
> 
> - WhyMe


Using the commonly used conductors, THHW or THHN, for number 12 and 10, the practical limit is 6 current carrying conductors in a conduit. The derating starts at about 10 amps over the maximum over current device limit.

The NEC book is not a DYI manual for the layman ;-)


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## WhyMe (Feb 15, 2014)

> Using the commonly used conductors, THHW or THHN, for number 12 and 10, the practical limit is 6 current carrying conductors in a conduit. The derating starts at about 10 amps over the maximum over current device limit.
> 
> The NEC book is not a DYI manual for the layman ;-)
> 
> - TopamaxSurvivor


#12 you can get by with up to 9 current carrying conductors. I agree #10 is 6.


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## TopamaxSurvivor (May 2, 2008)

We have so many engineers specing limits on length of wire for voltage drop, nearly every circuit is pulled in #10 if it is to meet spec.

Are they doing anything like that on your coast?


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## WhyMe (Feb 15, 2014)

> We have so many engineers specing limits on length of wire for voltage drop, nearly every circuit is pulled in #10 if it is to meet spec.
> 
> Are they doing anything like that on your coast?
> 
> - TopamaxSurvivor


Sure do in large commercial and industrial installs.


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## TopamaxSurvivor (May 2, 2008)

I was surprised to see it in small strip malls where it was just a few feet beyond the specs. I wondered how many contractors are cutting corners and getting away with it?


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## TheFridge (May 1, 2014)

I'd be interest in the article allowing multiple 250v recepts on 1 circuit. The one with the gfci circuits not occupying the same raceway as well. Codebook stays at work so I don't have access to it.


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## TopamaxSurvivor (May 2, 2008)

I have been retired for 3 years and it has been at least 4 since I wired the airplane hanger. The guy wanted two outlets on a 30 or 50 amp circuit. I don't recall it specifically saying you can do it. I believe my research did not deny it. The inspector for rough in went over everything with a fine toothed comb since he had never inspected a hangar before. When I called for final, he was off that day. A different inspector came out and we went over everything with a fine toothed comb again since he had never inspected a hangar before. ;-(( The second one even called his supervisor a couple times ;-) I'm sure it was legal before the 2104 code came out. I took code update to keep masters license and they never mentioned any change that would affect it.


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## TajBuilder (Aug 6, 2008)

Article 210 of the NEC covers branch circuits. In a nutshell, you can use 15 amp receptacles on a 20 amp circuit, but you can't use 20 amp receptacles on a 15 amp circuit. You can have multiple receptacles on a 30 amp circuit provided that all receptacles are rated for 30 amps, no one receptacle has a load greater than 24 amps (80% of circuit rating), and the total load on the circuit doesn't exceed 30 amps.


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## TheFridge (May 1, 2014)

I was more referring to the part of the section of the article. I looked this problem up not too long ago and came up with a different answer. I don't remember how. I just remember I did. Misinterpretation most likely.


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## TopamaxSurvivor (May 2, 2008)

> Article 210 of the NEC covers branch circuits. In a nutshell, you can use 15 amp receptacles on a 20 amp circuit, but you can t use 20 amp receptacles on a 15 amp circuit. You can have multiple receptacles on a 30 amp circuit provided that all receptacles are rated for 30 amps, no one receptacle has a load greater than 24 amps (80% of circuit rating), and the total load on the circuit doesn t exceed 30 amps.
> 
> - Roy Turbett


Probably what I found. Is that the 2014 code?


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## WhyMe (Feb 15, 2014)

> Article 210 of the NEC covers branch circuits. In a nutshell, you can use 15 amp receptacles on a 20 amp circuit, but you can t use 20 amp receptacles on a 15 amp circuit. *You can have multiple receptacles on a 30 amp circuit provided that all receptacles are rated for 30 amps, no one receptacle has a load greater than 24 amps (80% of circuit rating), and the total load on the circuit doesn t exceed 30 amps.
> *
> - Roy Turbett


The NEC doesn't explicitly say the number of outlets on a branch circuit by circuit amps but the International Building Code does. Multiple outlet branch circuits are limited to 20A.


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## TopamaxSurvivor (May 2, 2008)

The NEC does set limits, but it is by load calc.

IMO, the electrical rules in new IRC, ect are attempts to reduce a complex subject to a few simple, one size fits all regulations so builders can use more unskilled labor. They will probably do it in residential units to the detriment of a few of us, US, who do not fit the mold.


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## TajBuilder (Aug 6, 2008)

According to the 2015 International Residential Code, "*Section E3297.4 Thirty Ampere Branch Circuits* - A 30 ampere branch circuit shall be permitted to supply fixed utilization equipment. A rating of *any one* cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch circuit ampere rating. [210.23(B)]"

I interpret this to mean that multiple 30 amp receptacles are permitted for "fixed utilization equipment" such as table saws and welders. The following section limits "general purpose" branch circuits to 20 amperes.


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## WhyMe (Feb 15, 2014)

I don't know where you got E3297.4 from. I don't believe the intent of E3702.4 is to allow a multiple outlet 30A circuit. It would clearly say so. I don't interpret "any one" as meaning to allow multiple connected. I believe it means any piece of plug connected equipment. E3702.5 clearly limits multioutlet branch circuits to 20A.

E3702.5 Branch Circuits Serving Multiple Loads or Outlets.

General-purpose branch circuits shall supply lighting outlets, appliances, equipment or receptacle outlets, and combinations of such. *Multioutlet branch circuits serving lighting or receptacles shall be limited to a maximum branch-circuit rating of 20 amperes.* [210.23(A), (B), and (C ) ]

E3702.4 Thirty-Ampere Branch Circuits.

A 30-ampere branch circuit shall be permitted to supply fixed utilization equipment. A rating of any one cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch circuit ampere rating. [210.23(B)]


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## TajBuilder (Aug 6, 2008)

I stand corrected on the section number and believe we are both referring to the same sections. However, in my original post I added the caveat "and the total load on the circuit doesn't exceed 30 amps." Section E3702.6, Branch Circuits Serving a Single Motor; and Section E3702.7 Branch circuits serving motor-operated and combination loads specify how the load is to be calculated and in the case of E3702.7 it is clearly referring to multiple loads. I can see where a separate circuit for each machine is desirable where one knows in advance that the maximum load will be exceeded because more than one machine is in operation at a time. But multiple machines on a single circuit make perfect sense for a one man shop where only one machine is used at a time and/or when machines get moved around as needs change.

Interpretation of this section of code is a common topic of discussion on many of the electrical forums and there is a lot of disagreement. The real bottom line is that you should check with your electrical inspector before you pull any wire to see what he will accept. Here is a link to one of the discussions on the topic with two points of view.

http://www.selfhelpforums.com/showthread.php?18920-Multiple-240V-30A-Outlets


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## Sarit (Oct 21, 2009)

I always thought the dedicated 220 circuit was done to avoid the gfci requirement which ultimately meant you can avoid the expensive of a double-pole breaker if you run a couple more wires.


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## WhyMe (Feb 15, 2014)

My understanding as in E3702.7 is "Fastened in Place" means hardwired. I'm not arguing that a 30A circuit can't have multiple loads, it can't have multiple receptacles to connect those loads as restricted by E3702.5. You need to look at the whole code, not just take one section without any regard to another section.


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## TajBuilder (Aug 6, 2008)

I'm not saying you're interpretation is wrong because many of the electrical forums point out that some inspectors also follow your interpretation. But if "fastened in place" means hardwired, why would E.3702.4 mention "any one cord-and-plug-connection"? Bottom line is the correct answer is the one your electrical inspector gives you and mine didn't have a problem with multiple 30 amp receptacles. But yours may have a different opinion.


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## TheFridge (May 1, 2014)

> I always thought the dedicated 220 circuit was done to avoid the gfci requirement which ultimately meant you can avoid the expensive of a double-pole breaker if you run a couple more wires.
> 
> - Sarit


Negative. Dedicated circuits aren't required to be gfci protected unless it's for a piece of equipment where it's a standard to do it. Pool or spa or jacuzzi. As far as I know.


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## TheFridge (May 1, 2014)

210.23 (B) 3 says yes on multiple cord and plug loads on one circuit.

430.24 says the circuit must be rated for all motors on circuit. No more than the typical 80% load on breaker with cord and plug.

What I have so far.


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## WhyMe (Feb 15, 2014)

> I m not saying you re interpretation is wrong because many of the electrical forums point out that some inspectors also follow your interpretation. But if "fastened in place" means hardwired, why would E.3702.4 mention "any one cord-and-plug-connection"? Bottom line is the correct answer is the one your electrical inspector gives you and mine didn t have a problem with multiple 30 amp receptacles. But yours may have a different opinion.
> 
> - Roy Turbett


I believe you are mixing apple and oranges. E3702.4 deals with general usage of 30A circuits for fixed utilization equipment and does not specify "Fastened in Place". There are a lot of nuances in the way code is worded and causes the conflict in interpretation. That's what happens when a bunch of want-to-be lawyers write the code. As you say it's all up to how your local AHJ sees it. My AHJ doesn't allow multiple receptacle outlets on a 30A circuit and they cite E3702.5 and there is no other overriding code section. Another thing that is misinterpreted in code is the term "outlet" VS "receptacle". The code doesn't disallow multiple outlets on a 30A circuit because an outlet is a point where power is taken and may be a hardwired point. That's why E3702.5 says receptacle outlets and not just outlets. Good topic and have enjoyed the debate. It would be nice if the powers to be would have the code rewritten in plain English and use a few more words where needed so to be not cryptic.


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## TajBuilder (Aug 6, 2008)

> .... Good topic and have enjoyed the debate. It would be nice if the powers to be would have the code rewritten in plain English and use a few more words where needed so to be not cryptic.
> 
> - WhyMe


+1


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## TheFridge (May 1, 2014)

I saw the "any one" statement when referring to multiple motors on the same feeder so I have a heavy lean in favor of multiple.


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## TajBuilder (Aug 6, 2008)

> I saw the "any one" statement when referring to multiple motors on the same feeder so I have a heavy lean in favor of multiple.
> 
> - TheFridge


I agree. But I can also see WhyMe's point of view as its shared in a number of other forums. Some say that their local inspector permits multiple receptacles, some say he "likes to see" only one machine per circuit, and others say their inspectors don't allow it. Some take the view that if the code doesn't specifically prohibit it, its allowed. But others say that if the code doesn't specifically permit it, its not allowed.


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## TheFridge (May 1, 2014)

Yeah I don't see a "shall not". I'd argue with an inspector an call my chances of winning pretty good.


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## WhyMe (Feb 15, 2014)

> Yeah I don t see a "shall not". I d argue with an inspector an call my chances of winning pretty good.
> 
> - TheFridge


You'd lose. E3702.5 says no multiple receptacles on branch circuits greater than 20A. Why is that so hard to understand? There is no written exception to this. E3702.4 is just setting the 80% amp limit if one piece of equipment is cord and plug connected. Section E3702.4 purpose is not to establish that more than one receptacle is allowed on a 30A circuit.

Edit: Of course this is all mute if your AHJ didn't adopt the IRBC or has their own interpretation.


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## TopamaxSurvivor (May 2, 2008)

I feel for you guys with conflicting 2 codes, NEC and IRC when the state adopts both ;-)


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## WhyMe (Feb 15, 2014)

> I feel for you guys with conflicting 2 codes, NEC and IRC when the state adopts both ;-)
> 
> - TopamaxSurvivor


No conflict here. NEC is basis for IRC electrical. The IRC goes further to define/restrict some uses. Virginia Uniform Statewide Building Code (USBC) is based on the IRC. In VA the USBC takes president over the NEC/IRC.


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## TheGreatJon (Jan 9, 2015)

There is a lot of good information on this thread. I've done a decent amount of wiring on my shop, and this would've been handy stuff to know before I started. As it was it took me forever to muddle through it. Bookmark this if you're ever going to be doing some handyman electrical stuff.


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## mprzybylski (Nov 21, 2011)

> There is a lot of good information on this thread. I ve done a decent amount of wiring on my shop, and this would ve been handy stuff to know before I started. As it was it took me forever to muddle through it. Bookmark this if you re ever going to be doing some handyman electrical stuff.
> 
> - TheGreatJon


Agreed. I've bowed out of the conversation at this point as I have all my questions answered and have nothing to contribute to this discussion but I wanted to thank everyone who participated and helped get me on the right track.


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## TajBuilder (Aug 6, 2008)

I found the section of the IRC that settles the issue on whether multiple receptacles are permitted on a 30 ampere circuit. Section E4002 covers receptacles. Note that "receptacles" is plural. The NEC cite is 210.21(B)(3).

Section E4002.1.2 *Two or more receptacles* Where connected to a branch circuit serving two or more receptacles or outlets, receptacles shall conform to the values listed in Table E4002.1.2. [210.21(B)(3)].

The table confirms my original post, "In a nutshell, you can use 15 amp receptacles on a 20 amp circuit, but you can't use 20 amp receptacles on a 15 amp circuit. You can have multiple receptacles on a 30 amp circuit provided that all receptacles are rated for 30 amps, ...."


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## TopamaxSurvivor (May 2, 2008)

> I found the section of the IRC that settles the issue on whether multiple receptacles are permitted on a 30 ampere circuit. Section E4002 covers receptacles. Note that "receptacles" is plural. The NEC cite is 210.21(B)(3).
> 
> Section E4002.1.2 *Two or more receptacles* Where connected to a branch circuit serving two or more receptacles or outlets, receptacles shall conform to the values listed in Table E4002.1.2. [210.21(B)(3)].
> 
> ...


Then there is no conflict if IRC allows general purpose 30 amp circuits. I don't recall if higher amps are OK by NEC. My code book is 2 cycles old now, not worth researching it ;-)


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## TajBuilder (Aug 6, 2008)

Correct. There is no conflict between IRC and NEC.


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## WhyMe (Feb 15, 2014)

> I found the section of the IRC that settles the issue on whether multiple receptacles are permitted on a 30 ampere circuit. Section E4002 covers receptacles. Note that "receptacles" is plural. The NEC cite is 210.21(B)(3).
> 
> Section E4002.1.2 *Two or more receptacles* Where connected to a branch circuit serving two or more receptacles or outlets, receptacles shall conform to the values listed in Table E4002.1.2. [210.21(B)(3)].
> 
> ...


I'll give you credit for trying to support your thinking but you are wrong. Chapter 40 is for specifying device ratings not circuit requirements. The table in 4002.1.2 is a straight copy from the NEC and is not defined as multioutlet in the NEC, it is for the purpose to state the amp capacity of receptacles required based on circuit amps. Table 4002.1.2 is not setting code allowances to have multiple receptacles on a 30A circuit. Chapter 37 sets branch circuit requirements, so E3702.5 is the end, no multiple receptacles on circuits greater than 20A.


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## WhyMe (Feb 15, 2014)

> Correct. There is no conflict between IRC and NEC.
> 
> - Roy Turbett


You are right, there is no conflict between the NEC and IRC, but it's because they serve two different purposes. The electrical section in the IRC is based off the NEC and has it's own modified requirements because it's for residential construction. There is no section in the NEC that states that multiple receptacles are allowed or disallowed on a 30A or higher circuit. But under the IRC which is residential only, multiple receptacles are limited to no higher than a 20A circuit.


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## TajBuilder (Aug 6, 2008)

> Chapter 37 sets branch circuit requirements, so E3702.5 is the end, no multiple receptacles on circuits greater than 20A.
> 
> - WhyMe


Its obvious we're never going to agree on this and your inspector has a different take than mine. Section E3702.4 covers 30 amp circuits and is referring to "fixed utilization equipment" while Section E3702.5 covers 20 amp circuits and is referring to general purpose branch circuits that supply "lighting outlets, appliances, equipment and receptacles." I would argue that my bench mounted radial arm saw and dust collector are "fixed utilization equipment" and are not subject to the 20 amp circuit limitation for general purpose branch circuits. They can therefore share the same 30 amp circuit subject to the load limitations I stated in my original post. And since Section E3702.4 doesn't specifically prohibit multiple receptacles, I would argue that they are allowed.

While we obviously disagree on the number of receptacles that are allowed on a 30 amp circuit, I think we both can agree that multiple 30 amp circuits are better than one because the equipment that is generally found on a 30 amp circuit (such as my 5 hp air compressor and 5 hp table saw) frequently use most, if not all, of the available capacity. But there is still an advantage of having multiple outlets because equipment does get moved around as needs change.


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## WhyMe (Feb 15, 2014)

> Section E3702.7 Branch circuits serving motor-operated and combination loads specify how the load is to be calculated and in the case of* E3702.7 it is clearly referring to multiple loads. * I can see where a separate circuit for each machine is desirable where one knows in advance that the maximum load will be exceeded because more than one machine is in operation at a time. But multiple machines on a single circuit make perfect sense for a one man shop where only one machine is used at a time and/or when machines get moved around as needs change.
> 
> - Roy Turbett


I agree that there can be multiple loads on a 30A circuit but following E3702.5 they cannot be connected via multiple receptacles. I'm sure you and everyone else are getting tired of hearing me say this. The linked topic you provided boils down to conjecture and debate over the NEC. Most debates do not take into account the IRC.


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## WhyMe (Feb 15, 2014)

> Its obvious we re never going to agree on this and your inspector has a different take than mine. Section E3702.4 covers 30 amp circuits and is referring to "fixed utilization equipment" *while Section E3702.5 covers 20 amp circuits *and is referring to *general purpose branch circuits *that supply "lighting outlets, appliances, equipment and receptacles."
> 
> - Roy Turbett


There lies your problem with understanding the written code. You inject things that do not exist in the code section. E3702.5 is* Branch circuits serving multiple loads or outlets*. It is not inclusive of just 20A circuits. It limits receptacles to 20A on multioutlet branch circuits. The section also refers to multioutlet branch circuits and not just general purpose. Oh I give up.


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## TajBuilder (Aug 6, 2008)

I sent the following email to my State electrical inspector this morning and received the following response.

"I live in Williamstown Township in Ingham County and pulled an electric permit for an unattached wood shop I built in 1997. At the time I hadn't purchased any equipment other than my table saw and air compressor that are on their own circuits. I also installed two 30 amp circuits with multiple receptacles for future fixed equipment with unknown loads such as a dust collector, planer and jointer. I also didn't know exactly where in the shop I would be locating the equipment. The State inspector didn't have a problem with this and I passed the inspection.

My question is does IRC E3702.4 permit multiple receptacles on a 30 ampere fixed utilization equipment branch circuit provided that all receptacles are rated 30 amps, no one receptacle has a load greater than 24 amps (80% of circuit rating), and the total load on the circuit doesn't exceed 30 amps? The reason I ask is that I may be adding a 220v fixed equipment branch circuit for a built-in radial arm saw and dust collector in an attached garage at a vacation home."

This is the response I got.

"E3702.4 Thirty-ampere branch circuits would be applicable. E4002.1 Rating and type, & E4002.1.2 Two or more receptacles would also apply. I hope this helps."


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## jimintx (Jan 23, 2014)

I wired my shop with many of the features discussed here as not allowable. All my shop wiring was completed in 2013.

- I have boxes with a 220v plug and a 110v duplex. I bought the covers for those from an electrical supply house. FWIW, that supply house did not think they were assisting me to violate any codes.

- I have 220v circuits with two outlets. I wasn't sure exactly where I would place the machinery, so i wanted built in flexibility. I know that I will never run two such machines at once, and for that matter, i have multiple 22v circuits so i could run them from different circuits if i wanted to do so.

- Mt shop has a double-wide roll up garage door to facilitate getting things in and out. However I do not have gfci outlets in it. I essentially hate the way those work, and i am personally willing to let a breaker trip rather than farting around with a gfci. (I know, I know - the electron movement police will chide me, but I simply don't agree.)

- In the city where I did this work, I did it just like Matt, the OP here wants to do, and no city inspection was involved. Also, "passing" inspection is not required to sell a house. Getting an inspection is required, but once you have the inspection, it is not a requirement to bring everything up to current codes. If so, I would never have gotten this house bought in the first place.

- I do have a dedicated sub-panel for the shop and some outdoor lighting. I believe that a dedicated, or nearly dedicated, sub-panel for the shop is the way to go.


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## WhyMe (Feb 15, 2014)

> This is the response I got.
> 
> "E3702.4 Thirty-ampere branch circuits would be applicable. E4002.1 Rating and type, & E4002.1.2 Two or more receptacles would also apply. I hope this helps."
> 
> - Roy Turbett


All I can say based on all my years of exposure to the code and application of the code here in Virginia I believe the application of E4002 to allow a 30A multioutlet branch circuit is wrong. I truly believe your inspector is misapplying the code. Have a good day.


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## TajBuilder (Aug 6, 2008)

Well he's the Chief of the Electrical Division for the Bureau of Construction Codes in the State of Michigan. Its like I said earlier, the correct answer is the one you get from your inspector and I respect that yours may have a different opinion.


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## WhyMe (Feb 15, 2014)

Matt, I apologize for running your post off the rails.


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## TajBuilder (Aug 6, 2008)

> Matt, I apologize for running your post off the rails.
> 
> - WhyMe


+1


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