Horse stalls. Beam and post construction , 132’ X 24’. Roof over ½ of area, or 132’ X 12’. Metal siding on back wall as well as 12’ on the 2 ends. 10 stalls and 1 tack room, each 24’ X 12’, with tack room in middle of building. Stalls utilize knock down corral fencing on all sides. Tack room framed up with plywood front and sides. Concrete floor in tack room, and concrete continues out 12’ from tack room to front of stalls, and includes a frost-proof water faucet (fed with plastic pipe underground). Concrete slab was poured using fiber instead of wire mesh.
Proposed: Install 60amp 4-wire panel fed from meter/disconnect on a remote pole. Loads include 1 150watt light located in the middle of each wing (each wing consists of 5 stalls) and 1 light and 2 gfci outlets in tack room. PVC conduit will be wiring method, with snap covers on switch and outlets. Grounding electrode system will consists of two 8’ ground rods with #6 bare copper as my GEC. Bonding with a bolted lug to the metal skin with a connection to the GEC. Neutrals and grounds will be separated in panel.
I seem to be having a problem understanding the requirement for the equipotential plane. Since there is no metallic equipment that may become energized, is the E- plane still required?
Or because I am bonding the skin of the building to the service, would the skin be considered “metallic equipment that may become energized”, thus requiring the E-plane?
Since the metal corral fencing is not bolted together anywhere, do I need to bond each (any?) of these to the service?
You can see a couple of pictures of the project at Photobucket .
Thanks.
Rick Miell

Here it's more a matter of knowing what was 'intended,' as opposed to what was 'written.' It can seem laughable, but the short form of the equipotential issue can be summed up with:

"Do I have a milking machine?"

That's pretty much what got the whole issue started. You didn't want your cow to step from an energized slab to a non-energized slab, or for your horse to nibble on wires without tripping the GFI.

In more technical terms, an 'equipotential plane' is one way to help 'lost' electricity get back to the panel, where it can trip the breaker. So, a key part of the issue is: where would the 'lost' electricity come from, and how would it get back to the panel?

Let's just, for the sake of argument, imagine that you had a powered conveyor bringing feed from outside, over that slab, and into that stable. In that situation, one might see the benefit to having the slab nicely bonded to the service, because a fault at the far end of the conveyor just might try to travel through the slab.

The use you propose does not require an equipotential plane.

As a design note, though, I'd suggest replacing that single light bulb with a pair of fluorescent fixtures. It'll make both the horse and the stablehand happier. You also might want to have an outside disconnect for the building (the Fire Dept. will love that!)

If it comes under 547 & the code says SHALL be installed to comply do you have a choice??? 547.10 (A)

No, Yoopersup, I don't read it that way. 547 only requires it if there is electrical equipment and metal 'likely to become energized.' From his description, it sounds like this clearly agricultural site does not require an equipotential plane.

Wheres it say thatin 547??
547.1 Scope This article SHALL apply ectect whats to say Electrical equipment is not be added at a later date.

547,10(A) Where Required.
547.10(A)(1) Indoors. Equipotential planes shall be installed in confinement areas with concrete floors where metallic equipment is located that may become energised and is accessible to livestock.

Similar language applied in (2) for outdoor locations.

Absent the means of energizing the metal, you don't need an E.P.

What happens in the future is another thing entirely. Article 90 is pretty plain that the NEC is not intended to address future possibilities.

Looking at the pictures of the stable, I just don't see it being an issue.

547.10 (A) 1 & 2 ???
2005 NEC theres 547.10 (A)
547.10 (B)
My code book does not have 1 & 2 ????
Scope 547.1 Says provisions of this article SHALL apply If (A) or(B) apply .
??????????????????

Interesting. I was using the 2008 edition.

The 2005 reads, in part, "containing metallic equipment that may become energized, and is accessible to livestock." That's where the E.P. is required.

So, we're still on the point of: is the metal present likely to become energized? With an all-PVC wiring method, and not accessible to the animals, I can't say it's "likely" to become energized. Nor can I stretch "may" to cover every possibility, however far-fetched. Were we to do that, there would be no need for the qualifier at all.

Nor do I consider fences and buildings to be "metallic equipment." Again, as with swimming pools, had the code panel meant 'all metal,' they would have said so. I don't see ANY equipment in the building under discussion - and I can't extend 'equipment' to cover a hend-held trimmer on an extension cord either.

You got a point I gotta admit. Be interesting to get others involved. Since metal siding & building metal would be required to be bonded . You could have a different potiental to ground between Fence, concrete, & metal building which in fact could get engerized. Wisconsin has a VERY Strick code on this for farms because farmers have lost so many animals there. Interesting sparing with you.
Yoopersup

That's what makes forums fun! An honest conversation. I also welcome other viewpoints.

For a less formal setting, drop in on the chat room!

I was reading thru this details and I am not really famuir with the OP's state regulations realted to the livestock useage however in state of Wisconsin we do have pretty strict section realted to the livestock useage and for the cement we have to use the rebar plus { the fiber may be ok in some area } grounding conductor go back to EGC ground rod at the mainload centre.

The Univeristy of Wisconsin did do the reshearch related to the stray voltage and enopointal plane set up I will attach the link later IMO I think someone in this forum did have a link some time back but I doubt it otherwise you can goggle it
It have pretty good artcale realted to this.

Merci,Marc

Thanks for the inputs. I was already leaning towards the non-E-Plane, for the same reasons given. It is nice to get replies that agree with what you think is correct, both code-wise and real world-wise.

Thanks again.

Rick Miell

French and Yooper are both in Wisconsin, and believe that the EP is necessary. This underscores the importance of checking with your local authorities.

Yoopersup is in Upper Peninsula of Michigan, We have lotta farms & Cattle up here also.

The State of Michigan (upper and lower peninsula) do not have electrical inspections in agricultural buildings. In fact the State law has exempted Article 547 out of their electrical code. The only thing subject to the electrical code on a farm is the Service and the residential building.

Yes George but most up here inquire & want them built safetly & to the ladest codes. Dead animals don't do anyone any good.
Yoopersup

Talk to the owners find out what their future plans are. If it is not required, tell them it would be way more expensive to go back and replace it. Let them make the call. If Art. 547 does not apply, it does not mean you can not still use it providing it does not violate other requirements. Be sure to put in your quote that you discussed with them and they declined. Reason being, years down the road, they decide to put in electrical equipment and something go wrong. Someone gets hurt, the finger pointing will start and the finger will be pointed at you. Odds are, nothing will ever happened, by documenting it, C.Y.A. and it takes only a few seconds.

Ernie- I agree with your perspective on installing per code albeit inspecting it is optional in Michigan. None of the State inspectors are making inspections under 547 because they have to enforce State Code. I have/had a couple farms in my area and they wanted them inspected and I made the inspections knowing I could not write a violation. The other issue is, if we do make inspections and have them make "corrections" and something goes sour, you rhetorically speaking, are on the hook and will have to be in court all by yourself with no support from the AHJ.

George .,

That kinda suprised me here and I don't know if you are famuair with Wisconsin Comm codes if not Let me bring you up the speed real quick here in Wisconsin we did change the code to make it instering the homestead is treated as resdentail codes however any non attached building we treat them as commercal codes they were in enforece just started not too long ago almost a year ago to clear up too many loopholes { some farmer try to abuse the codes by doing some crazy stuff }

So by doing this the commercal side of code really enforce it and they make it clear for any AG useage we have to have rebar in the contrete for EP set up { for all building livestock or not it will enforce it unless it is not zoned as AG then the rules will go out of the window }

Merci,Marc

I carry licenses in Wisc, & Mich, also inspectors & instructors in both so I know what both states require.
Yoopersup

Still, it's good to explain. In this thread we see a great example of where local practices / rules differ from the NEC.

This emphasizes to the OP, and everyone else: check your local rules!

Yoopersup:

That is good to know and you can see both way how it work out.

It the same way with myself I am well verised with Wisconsin and French codes but I have to becarefull not to get both mixed up.

Merci,Marc