[BrandonD]

Hi all,

I have two sheds and a horse stall on the property. A couple months ago I ran a subpanel to one of the sheds with the end goal of powering these buildings. I have a few questions and am looking for general guidance since you guys provided me with some very valuable guidance when I ran the subpanel. Below is a list of what I plan to do since I have the next two weeks off.

1) Replace a 120V receptacle powering the well water softener just outside the shed with the subpanel. It's currently wired on the same 240V circuit that the well is on (yikes). No specific questions here really.

2) Run three circuits within the first shed. The first shed will be used to power some mildly hefty shop tools. I plan on installing 20A receptacles using 12/2 wire in this shed, half of them on one circuit and half on another. The third circuit will be a 14/2 for lighting. I do have a specific question here. The shed is unfinished inside so all of the stud bays are accessible. Can I just run 12/2 romex directly from the subpanel and (drill) through the studs to the receptacles? I don't imagine it'd be easy to bend metal conduit into my 16" stud bays for the length of the wall.

3) I will run two 20A circuits using THWN in two metal conduit runs from the subpanel to the 2nd shed. One circuit will power a receptacle and the lighting in here (very light electrical use in this shed). The second circuit will enter this shed to two switches and will go from the two switches to the horse stall (one switch powering a flood light and another switch powering a receptacle). Is the following diagram the best way to wire the two switches and the flood light and receptacle they control? Can I put the two switched hots, common ground and neutral in a single conduit or do the two hots have to be kept separate?

Thanks!

 

[tylernt]

The shed is unfinished inside so all of the stud bays are accessible. Can I just run 12/2 romex directly from the subpanel and (drill) through the studs to the receptacles? I don't imagine it'd be easy to bend metal conduit into my 16" stud bays for the length of the wall.

NM (Romex) needs protection, so you can run Romex through the studs only if you plan to then sheet the walls with something like drywall, plywood, OSB, etc.

If you don't plan to sheet, perhaps BX (armored flex) could be run in the stud bays without additional protection?

3) I will run two 20A circuits using THWN in two metal conduit runs from the subpanel to the 2nd shed.

Have you considered using a MWBC here? Two hots, one neutral, one ground, all in one conduit.

 

[BrandonD]

Thanks for the feedback. BX cable sounds like the better option regardless -- I was never too fond of the idea of having exposed NM in my work shop, even if it was within stud bays. Can someone confirm BX is fine running from the subpanel to the receptacles without additional protection?

I've thought about using a MWBC for the shed and stall and am not entirely opposed to it. I just have the room to do them independently and I wouldn't save much on supplies since these building are all in the same vicinity. I'd just like confirmation that my wiring diagram is correct. I'm a bit worried about the amount of pigtails in the box for the dual flood light.

 

[BrandonD]

Here's one of the bigger guys in my 1st shed. An older table saw that I got from my great granddad. Will connecting the single plug out of this into a 120V 20A receptacle be sufficient? I thought amps changed between 120V and 240V... so not sure if it's 20A at 120V or 240V?

 

[TTW]

Love to see a shot of the whole thing!

Is there an info plate on the motor?

 

[BrandonD]

Went out to get the info off the motor plate. It has "12/6" in AMPS box, so I'm assuming it pulls 12A at 120V and 6A at 240V? So I could plug this into one of the 120V 20A receptacles... or would you recommend I run a dedicated 120V 20A circuit for it after taking into account the larger start up pull etc?

I will try to get some pictures of it soon. It's too dark to take a picture of it now. I also received an equally as old planer from him. Both weigh an insane amount and punctured holes in my truck bed liner. Does anyone know of any good online resources for cleaning up old machinery? My dad recommends I really clean them up before attempting to use them because it's been years since they last ran. I don't have a lot of mechanical experience but it's something I'd like to learn.

 

[Jim Port]

You can only have one circuit or feeder to an outbuilding. A MWBC counts as one circuit. The feeder will require a subpanel to be installed.

 

[BrandonD]

Blah. That sucks. So I can't even have a 2nd circuit come up and just enter the shed to a light switch box and back down out of it? But I can have it two inches out there in the open mounted to the exterior of the shed? That's kind of lame.

Right now that shed has conduit running up from the floor to a receptacle to a light switch and then to a light. I was planning on just utilizing this for the shed circuit. If I went the MWBC route could I still utilize this setup? Is the updated diagram below correct?

Finally, when wiring the MWBC in the subpanel, I connect the shared ground and shared neutral to the separate ground and neutral bus bars like normal. Then I connect one hot to a regular single pole 20A breaker and the 2nd hot to a separate regular single pole 20A breaker? With no jumpers, tandem bars etc between the breakers correct?

 

[BrandonD]

Additionally, I wanted the circuit powering the stall's light and receptacle to be on a GFCI breaker. Can I still do that with the MWBC circuit (so just the one 20A would be GFCI)? If not, I suppose I could install a GFCI outlet before the flood light.

 

[tylernt]

Finally, when wiring the MWBC in the subpanel, I connect the shared ground and shared neutral to the separate ground and neutral bus bars like normal. Then I connect one hot to a regular single pole 20A breaker and the 2nd hot to a separate regular single pole 20A breaker? With no jumpers, tandem bars etc between the breakers correct?

Actually, recent code revisions (dunno if NEC 2008 or 2011) do require a handle tie now. You can use regular single pole breakers though, just make sure they installed adjacent to each other so they are on opposite legs (don't use a tandem).

Also, I think you might need a service disconnect as close as is practicable near the conduit entrance on the second shed? I've heard of a 4-way light switch (each pole switching one leg of the MWBC) being used for this purpose though, so, not expensive.

As for GFCI, yes, GFCI is totally compatible with MWBC. You can put GCFI on just one leg or both if you wish. However, after the GCFI, the neutrals need to remain independent. I.e., don't tie the line side and load side neutrals together.

 

[tylernt]

So I could plug this into one of the 120V 20A receptacles... or would you recommend I run a dedicated 120V 20A circuit for it after taking into account the larger start up pull etc?

I would think the startup inrush would only be a problem if you were running other things at the same time, like a dust collector. So just make sure your dust collector and table saw land on different circuits -- don't see a need for a dedicated circuit.

 

[BrandonD]

Thanks for the advice. I think I will go with the MWBC route. Can someone confirm the wiring diagram in post #8? I've never wired a MWBC before so just want to be sure. Additionally, tylernt, you mentioned a GFCI breaker would still work but the neutrals had to be kept independent. Not entirely sure what you mean here, are my neutrals kept independent in my diagram? And finally, will I be able to find a "handle tie" for the two breakers at a big box store like Home Depot and Lowes?

 

[tylernt]

Whoops sorry I missed that you wanted a breaker. No, since GFCI needs it's own neutral, you wouldn't have a MWBC anymore because you'd have to run another neutral. However, you can put a GFCI device (receptacle or deadfront) in the second shed or in the stall itself.

 

[BrandonD]

Ok. I will just do that then. I think I already have a GFCI weather resistant receptacle kit already actually.

Still no one has confirmed my wiring diagram in #8. Perhaps I'm just too paranoid, but would like someone with more experience than myself to OK it. I know just enough to get myself and others hurt and want to be sure I'm doing this right. I *think* I have it wired correctly, but not sure if I'm allowed to run a 2nd hot conductor through receptacle boxes, switch boxes etc (see the black conductor coming from the shed). Additionally, not sure if there will be an issue with the flood light box as it has a number of large pigtails in it. I suppose I could wire the outlet first, that would free up some room in the light box.

 

[tylernt]

would like someone with more experience than myself to OK it.

Yeah, I'm not any more qualified than you, hopefully someone else can help us out here.

not sure if I'm allowed to run a 2nd hot conductor through receptacle

I've seen this done. I don't know that you are supposed to run the wire unbroken though, usually I see the pass-through wire cut and rejoined with wire nuts.

Additionally, not sure if there will be an issue with the flood light box as it has a number of large pigtails in it.

It all has to do with cubic inches of box fill. The NEC is quite specific on how many wires and connections you can make in a box of a given size.

If you don't want to do the math, or your calculation ends up with too much box fill, just buy a bigger box -- they typically come in several sizes. Get the one with the largest cubic inches you can.

 

[BrandonD]

Your advice has been helpful and I appreciate it. Hopefully a sparky will come along and see this.

 

[mpoulton]

Also, I think you might need a service disconnect as close as is practicable near the conduit entrance on the second shed? I've heard of a 4-way light switch (each pole switching one leg of the MWBC) being used for this purpose though, so, not expensive.

A double pole switch, but not a 4-way. They look identical but do different things! A 4-way switch would not disconnect power, but just swap the hot legs when you flip it. A simple double pole switch would be fine, and Lowes/HD carries them.

As for GFCI, yes, GFCI is totally compatible with MWBC. You can put GCFI on just one leg or both if you wish. However, after the GCFI, the neutrals need to remain independent. I.e., don't tie the line side and load side neutrals together.

Since he was asking about using a GFCI breaker rather than receptacles, it really doesn't work with a MWBC. Since the neutral downstream of the GFCI cannot be shared, there's now ay to use a single pole GFCI breaker on a MWBC. You can get double pole GFCIs, and those are fine on a MWBC, but they are very expensive. Better to just use GFCI receptacles, unless you need the protection for a shallow-buried UF cable feeder.

 

[tylernt]

A double pole switch, but not a 4-way. They look identical but do different things!

D'oh, thanks for the correction!

 

[BrandonD]

Thanks mpoulton. Any comments on the wiring diagram in post #8?

Love to see a shot of the whole thing!

Is there an info plate on the motor?

Here you go. Not the best of pictures...

http://s1311.beta.photobucket.com/user/BrandonD00/library/Old%20Table%20Saw

http://s1311.beta.photobucket.com/user/BrandonD00/library/Old Planer

I found an online community for old wood working machinery. I'm going to post on there to get some advice on cleaning these up before I use them. Will be nice to be able to use these guys but won't get full use of them until the workshop is built!

 

[TTW]

If you paste the IMG code from photobucket, the pictures will show here.