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#77342 05/23/01 09:43 PM
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Glenn;
i can sense the point you pose in the posts there , but short of the ROP's , that BB has the ear of Batterymarch Park.

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#77343 05/23/01 10:00 PM
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In their defense, with the new thread I received some useful answers.

I'm with Mike on the 100A Feeder thing though! Guess I'll use #2 SER Al on 'em until I tick off an AHJ!


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
#77344 05/23/01 10:46 PM
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You guys must remember, the IAEI forum is hosted by the Michigan Chapter, not the International Office. I e-mailed Phil Cox a question about the IAEI membership bonus point program, and he replied back to me. He had not heard of that forum. So, it's up to us to make sure that our replies are factual, and give article & section numbers when required.

Rick Miell

#77345 05/23/01 11:14 PM
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Uhhh..2 out of 3 posters are ECN members...
They already knew me... (Thanks Steve and Don... Rick too) JD Dewitt the only non-ECN poster, that I know of...

Steve, you're the Bonding and Grounding guru anyway; may as well have the thread here amongst buddies as to talk between us over there... I'll suggest the Ufer in the entrance ramp idea,... What is a voltage gradient ramp? I kinda know what it is for, but no idea otherwise... Details...I need details! [Linked Image]

-Virgil


-Virgil
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5 Star Inspections
Member IAEI
#77346 05/24/01 06:08 AM
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If anything else, the depth and detail of the responses are worth reading in the IAEI BB. Many lead me to investigate the current ROP's , where said issues may be in the process of being addressed. This is testimonial to the 'chat level' there, so i understand why it's a 'take no prisoners' room. [Linked Image]

So Virgil,
I've been struggling with 250 for some time, ask a lot of Q's, that's all. what's 'voltage gradient', i suppose the term implies that stray voltage could not exist in different readings given the amount of bonding.
note the same term is applied to pools in 680-22 and the intent of it being an isolated entity.
Consider also the theory, in that only energized equipment can constitute a return path, the point being that the bonding of such items, and/or it's direct line of sight back to the power source would be what is most pertinent to bond. Note rop # 3720 mentions Mich State U as having done studies on the topic, that would be good info if we could access it.

The pad being poured, i would simply make the best of the situation here. There is no harm in running a #2cu around the pad, loop it thru as many G-rods as you can, maybe a bag or 2 of bentonite, and hit at least all 4 corners of the pad's rebar via J-hammer at points where the sill plate will hide the damage. Note the article does not go into detail on HOW this bonding is done....

Note 250-32(e) is for a reason, probably to exclude any opportunity for parrallel paths.

hope this helps, maybe others will comment on the fix for this, i call this the NEC's "field of dreams" mentality, assuming other trades ( or manufacturers)will acknowledge their wishes.
It would seem this requirement would be just as easy as requiring cows to sing the national anthem on sunrise.. [Linked Image]

have you ever said "equpotential plane" to a farmer? most would probably tell you to land it elsewhere....

[Linked Image]






[This message has been edited by sparky (edited 05-24-2001).]

#77347 05/24/01 09:44 AM
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Sparky,
The connection to ground is not what is important here. The bonding of everyting together to make sure there is no voltage between anything that the cows can contact is what needs to be done. That means the concrete must be bonded to the electrical system. Cows are very sensitive to small amounts of voltage and it will cause loss of milk output.

Virgil,
The voltage gradient ramp is a system to reduce any stray earth voltage between the inside and outside of the barn to a level that the coew can't detect. It is often accomplished by installing conductive rods bonded to the building bonding system on a 30° to 45° angle into the earth at the entrances to the building. The deep end is away from the building. This should reduce any voltage gradient to a level that the cows won't feel. Remember that the step potentional for a cow is between front and back feet.
Don(resqcapt19)


Don(resqcapt19)
#77348 05/24/01 01:31 PM
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Don,

Quote
Remember that the step potentional for a cow is between front and back feet
That's a good point to bring up as We 2 legged creatures might not think of that. The whole 'Bird on a Wire' question (as discussed many moons ago) may have a completely different answer if it was 'Cow on a Wire' [Linked Image]

'66

I'll take a look around and see what I come up with. I think I remember a short Article on it in EC Magazine a ways back and it was a topic of prolonged (sometimes Humorous) discussion in one of the Safety Listserves I subscribe to.

[Linked Image]
Bill


Bill
#77349 05/24/01 02:56 PM
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Bill,
that might be useful
Don,
I stand corrected, thank you.
All;
perhaps some of the 'fixes' that would accomodate an existing dairy farm would apply here?

[Linked Image]

#77350 05/24/01 05:56 PM
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Bill
#77351 05/24/01 07:36 PM
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Good links Bill!
Note the peak load readings on one link were all N to G, water bowl to flr, feed bin to flr, etc.
There seems to be much focus on N to G , and metal objects. So would the effect be lessened by substituting composites for conductables , and running all on 220V ?

[Linked Image]

[This message has been edited by sparky (edited 05-24-2001).]

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