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#25332 - 05/05/03 10:29 AM Grounding issue: Blue tarnishing in shower
Electric-Ian Offline
Registered: 12/12/01
Posts: 19
Loc: Mazomanie, WI, USA
Hi everyone,

Got a call to check out a situation where this new house (3 years old) has one shower that has a blue ring on the bottom of the tub and the faucet/drain are tarnished blue. There are five bathrooms in this house and only one bathroom has this problem. It is also the last bathroom on the water pipeline (yes, all copper).

From what the owner has told me, he has called one plumber and two electricians before me and the problem still has not been solved (I don't know what has been done yet). The plumber told him that this bathroom was receiving some stray voltage that reacts with the copper piping, thus turning the particular minerals in his water blue. I have not been to the house yet to inspect the main panelboard or any of the bonding techniques, but am going over there tonight.

Have any of you run into this? From what I understand, a grounding ring was suggested, but this house has two large cement driveways and a large underground network of irrigation piping which would make this solution quite labor-intensive. Any help would be greatly appreciated. Thanks!

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#25333 - 05/06/03 02:04 AM Re: Grounding issue: Blue tarnishing in shower
Trumpy Offline

Registered: 07/05/02
Posts: 8560
Loc: SI,New Zealand
Is it the lowest tap in the house?.
It sounds like Galvanic corrosion, I once had a bathroom tap that had this problem, but I'll be blowed if I can remember how I fixed it, either!.
Let's face it, these days if you're not young, you're old - Red Green grin
#25334 - 05/06/03 06:48 AM Re: Grounding issue: Blue tarnishing in shower
Electric-Ian Offline
Registered: 12/12/01
Posts: 19
Loc: Mazomanie, WI, USA

Thanks for your response. It is not the lowest tap in the house, quite strange. I did go over there last night to scope it out. The prior electrician did a great job making sure the pipes were well grounded throughout the house. The only little thing that stuck out to me was some of the grounding clamps that bonded the grounding conductor from the main panel to the main water pipe were copper, and some were another sort of metal that I have not seen or used before (they looked like galvanized metal). The reason I say this is that all those clamps that were not copper were very corroded against the copper pipes and didn't look like there was a solid bond between that and the pipe. And according to the owner these clamps were installed not even two years ago. I'm not giving up yet, but am pretty stumped!



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