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#3547 08/21/01 09:48 PM
Joined: Nov 2000
Posts: 2,236
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An estimate for a rewire turned into a troubleshooting call today... "Getting shocked by the tub" was the red flag...

Sure enough, (while in the middle of panic on another job to finish a rough-in...) the volt-tic was singing and flashing when touched to the drain... The Fluke read 35 Volts to the water pipe...

Dismantling the vanity light-medicine cabinet provided no answers, but it is on the same circuit...

So I go down in the basement to see if I can find any voltage readings that were equal or more than 35V to hopefully point me to the source... Testing with the volt-tic first, I found that it would readily sing even on the renovated PVC drain pipes connected to the tub and sink !!!

Running out of time and needing to get back to the jobsite (Allegheny Power had shown up to connect...) and after finding out that the tub had been recently reglazed and the customers were to not use the tub for another five days anyway, I begged them to allow me to return tomorrow, and to please not use the tub or sink until I say it's OK...

Anybody got a guess?

[Linked Image]


[This message has been edited by sparky66wv (edited 08-21-2001).]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
#3548 08/21/01 10:37 PM
A
Anonymous
Unregistered
My guess is that if you get "them" bonded, perhaps the OCPD might operate.

There must be a lot of iron in the water.

("them" be anything showing a potential difference starting in the basement.)

Why were they asking for a re-wire? Why wasn't the tub guy shocked?

#3549 08/22/01 04:47 AM
Joined: Oct 2000
Posts: 5,392
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Virgil;
when it rains it pours....
tape your volt-tic on & to the pipe, or position whatever meter you have to read the 35V, then start flippin' breakers. At least you may find the offending circuit , as it may be some rx simply making contact with a pipe anywhere. If your luck enough to make good on this, a point to point check on said circuit may be needed to reveal the culprit.

#3550 08/24/01 05:48 PM
Joined: Nov 2000
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[Linked Image from kellyelectric.electrical-contractor.net]

This picture shows my Volt-tic lit up... touching the PVC drain pipe...

[Linked Image from kellyelectric.electrical-contractor.net]

This picture shows the Volt-tic dead an inch away from the PVC to show that it isn't stray voltage making the whole area "hot"...

All the pressurized lines are 0 volts, the tub drain was 32.6V TRMS, the sink drain was 33.4V TRMS, the vent pipe in the attic was 44.2V TRMS.

Bonding the vent pipe would cure the sink, bonding the sink would cure the vent pipe, but the tub had to be bonded separately to show 0 volts.

The PVC in the pictures is between the tub and sink, retrofitted to old galvanized drain pipes in the walls, and the vent pipe in galvanized, but 90's into the chimney chase and and doesn't come back into view until up in the attic.

There are no obvious shorts, I even completely removed the medicine cabinet/ vanity lights...

Bonding seems to "fix" it but I'm afraid of creating a high resistance short that could worsen and cause a fire before it trips anything.

It's an old 60A fuse box...BTW...

I've searched everywhere but the chimney chase, and it would be very invasive to get there...

They want a total service change and rewire this Sept, so can I bond it for now or what?

[This message has been edited by sparky66wv (edited 09-04-2001).]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
#3551 08/24/01 07:22 PM
Joined: Mar 2001
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Possible a "false ground". This is when someone decides to replace a 2-wire receptacle with a 3-wire grounding type, and there is no ground in the box. They jumper the neutral to the ground terminal of the receptacle. Or, try disconnecting the individual branch ckt. neutrals at the box, then turning the breaker back on. If there is a change in your readings, or, if the circuit is still functional, this would point to a parallel neutral path.

#3552 08/25/01 12:29 AM
Joined: Aug 2001
Posts: 1
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Sparky,

Is this hot tub GFCI protected?

#3553 08/25/01 02:12 AM
Joined: Nov 2000
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I'm sorry, I haven't made myself clear... It's just a bathtub that is "hot"... a little play on words...Pardon the pun...

No "Jacuzzi" or Spa...

Just an old iron tub with about 35 volts on it!

Redsy... I'm suspicious that the house is absolutely full of "false grounded" recepts... Lots of Three-hole recepts with old two-wire NM feeding them... Haven't torn into any yet to see if they are (ahem) "bonded" to use the term loosely...

I'll make it a point to look tomorrow.

As far as bonding the pipes and "calling it good" until the rewire... Am I merely turning an electrocution hazard into a fire hazard?


[This message has been edited by sparky66wv (edited 08-25-2001).]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
#3554 08/25/01 05:43 AM
Joined: Oct 2000
Posts: 5,392
S
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Virgil,
the tub has become part of the circuit, you need to isolate which one...

#3555 08/25/01 09:05 AM
Joined: Mar 2001
Posts: 2,056
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I'm not too clear, visually on the bonding solution. However, if you do it, take an amp reading on the bond wire. That will tell you if there is now a fire hazard.

#3556 08/25/01 09:26 AM
Joined: Nov 2000
Posts: 2,236
Likes: 1
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I have isolated the circuit (#3 of 4 fuses), same one for the bath, and about one third of the recepts and lights in the house. Typical old service.

Yep, reading the current would be prudent, how much is acceptable? Only, say 0 to 1A?




[This message has been edited by sparky66wv (edited 08-25-2001).]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
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