Winery bonding

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George Stolz

George Stolz

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Hospital Master Electrician
The following was originally posted by sparky_magoo in another thread:
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I have been working in wineries lately. CA central coast wineries are growing exponentially. I have been hooking up new fermentation tanks. The only power on the stainless steel tanks is 24 VAC for the refrigeration control system. I bond the tank with the drain wire from the 18/2 which feeds the temperature control module. It seems to me that these huge steel tanks should have serious bond wires. They have no bond wires at all. Before I connected any of my wires, I metered from each tank to a hot wire on my drop light. My Fluke always registered 115+ volts to ground. The only ground I could see was the six legs touching the concrete. When I performed the test, the concrete floor was wet. They were pumping wine out of existing tanks and hosing down the floors.

Is contact with the concrete floor an adequate bond? Why did my Fluke register 115 VAC ?

In order to pump wine in or out of the tanks, we use cord connected 480 VAC motors mounted on four wheel carriages which resemble push mowers. If one of these hoses connected to the fermentation tanks had a fault, couldn't someone fry. Yes the hoses are non-metallic, but couldn't the tank somehow become energized? We do work in most of the wineries around here and they are all the same.
 
Re: Winery bonding

I thought it was off topic, and deserved it's own. :)

It seems to me that these huge steel tanks should have serious bond wires. They have no bond wires at all.
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What is going to energize the tank?

Before I connected any of my wires, I metered from each tank to a hot wire on my drop light. My Fluke always registered 115+ volts to ground.
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That is interesting, but not conclusive. Your meter doesn't pull any amps. Without a load, a incidental ground fault current path could look very good, under load it could open - you have no idea about how the circuit is completed through the tank. :)

The only ground I could see was the six legs touching the concrete. When I performed the test, the concrete floor was wet. They were pumping wine out of existing tanks and hosing down the floors.

Is contact with the concrete floor an adequate bond? Why did my Fluke register 115 VAC ?
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I presume the tanks are bolted to the floor with j-bolts or anchors of some kind. Whether these bolts are properly bonded to the Ufer beneath them or making incidental contact is open to question. I imagine this is the reason it completes a circuit to ground.

In order to pump wine in or out of the tanks, we use cord connected 480 VAC motors mounted on four wheel carriages which resemble push mowers. If one of these hoses connected to the fermentation tanks had a fault, couldn't someone fry.
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Not if the receptacles, the cords, and all the metallic components that come into contact with that 480V motor are properly bonded, and a grounded conductor is bonded to the service disconnecting means. If this is an ungrounded 480V system, then a ground fault will not open an OCPD. It would take a second fault to do so (to create a phase-to-phase fault).
Yes the hoses are non-metallic, but couldn't the tank somehow become energized? We do work in most of the wineries around here and they are all the same.
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Well, in the real world, the wine would act as a conductor, IMO. But so long as the circuit serving the pump and the pump itself is properly bonded, that is irrelevant. If there is a short to the case of the 'lawn mower', then that should open an OCPD. The tank becoming energized really isn't an issue.

IMO. :)

[ October 14, 2005, 08:00 AM: Message edited by: georgestolz ]
 
Re: Winery bonding

The tanks aren't bolted to the floor. The head winemaker feels he is better off letting the tanks float during an earthquake. There is no ufer for the tanks.

It is a grounded 480 VAC system. The 24 VAC control system is supplied by a 120 VAC primary x-frmr. The drain wire in the LV power cable bonds a brass solenoid which is isolated from the tank by PVC pipe. The drain wire also lands on a terminal strip for the plastic encased microprocesser temp. controller. The drain wire doesn't bond to the tank.

I used the Fluke to check the tank to hot voltage because the leads on my Wiggy are to short to reach. It was after hours, on my time, and I needed to get home. The wife gets POed when I stay late at work w/out OT. BTW, I was sampling their product while playing with the networked temp control system. The owners can access the temp network via internet from anywhere. Pretty cool.

I'm not sure anything is likely to energize the tanks. The 480 VAC pump is isolated by the hose.
It just seems to me a huge stainless tank ought to be bonded to the electrical system. The winemaker
argues nothing will energize his tanks. He has just enough electrical knowledge to make him dangerous.

Other wineries I have worked for bolt their tanks to the concrete pad and bond the.
 
Re: Winery bonding

Originally posted by Johnny Gooch:
Is she properly bonded?
Johnny
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Not any more. We cashed in all of our bonds and blew the money at an incredible havest festival put on by this winery Friday night. 95 of the 188 wineries here participated in the annual event. I spent a weeks pay on two cases of the finest wine we have ever tasted. At least she'll be happy for a while. I will try not to drink and post.
;)
 
Re: Winery bonding

Why do you hate wine? I just came back from another incredible party. We just came back from a harvest party at the only winery better than the one I worked at last week. He is also a long time customer. If any of you on this forum want to do a CA central winery tour, PM me and I will make sure you have an ultimate experience.
 
Re: Winery bonding

George, have you ever tried the finest wines in the world? You don't have to drink to get drunk. The taste of a really fine wine is incredible. There is nothing like it. :p

edited to correct spelling

[ October 17, 2005, 12:51 AM: Message edited by: sparky_magoo ]
 
Re: Winery bonding

Originally posted by sparky_magoo:
George, have you ever tried the finest wines in the world?
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Maybe not, but I've tasted stuff that other people had said, "Mmm, this is good wine." I didn't much care for it. :D
 
Re: Winery bonding

"Hello, I must be going. I cannot stay, I came to say I must be going . . .
"I'm glad I came but just the same I must be going, la-la . . ." - Groucho Marx in Animal Crackers
 
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