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#11652 07/18/02 04:00 PM
Joined: Aug 2001
Posts: 58
K
ken m Offline OP
Member
anyone have any ideas regarding that voltage tingling when touching the metal ladder as you climb out of the water? boat docks around here (western SC)are typically wired from a house circuit that is run underground to a pole and terminated either in a single unit breaker box with a gfi or a gfi receptacle. from that point a cord and plug runs along the dock gang-walk in conduit and onto the dock which may feed a light, an outlet for a battery charger or a boat lift.
this "voltage" is felt with nothing connected.
electricans have tried using ground rods, running #4 bare wire around the dock but to no avail. any ideas? thx., ken m

#11653 07/18/02 05:53 PM
Joined: Oct 2000
Posts: 4,067
Likes: 3
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Ken,

Are you touching a boat when this happens, or just coming out of the water? Does this happen when the circuit is turned off in the House?

Bill


Bill
#11654 07/18/02 10:46 PM
Joined: Dec 2000
Posts: 4,289
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As well as your system you might check on the neighbors.
It could be you've got the best grounded boat dock in town!!

#11655 07/19/02 06:02 AM
Joined: Aug 2001
Posts: 58
K
ken m Offline OP
Member
i probably need to explain a bit further...yes bill, while in the water and you touch the metal ladder is when the sensation is felt. the docks are composed of wood planking over metal framework which sets on encapulated foam floats. then from each of the shore side corners are steel cables attached to a land based metal supports driven or cemented into the ground. some of the docks that have this problem have pumps mounted on them. (not submersible)ususlly 120v for washing boats or cleaning fish. also neighboring docks are at least 50' away.
one thing i did learn was the local power co. has lines running across the lake at various locations???? thanks for the comments, ken m

#11656 07/19/02 06:05 AM
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ken m Offline OP
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this situation is with power on only.

#11657 07/19/02 08:33 AM
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Ken,

If it is with power on only I was thinking there might be some 'leakage' in the wiring that comes from the House. (I figured if it was on the load side of the GFCI out there it would trip) Do you know anything about the wiring method coming from the house, and is it in good condition? Can you disconnect that wiring and try feeding the dock another way temporarily to see if the problem goes away?

Bill


Bill
#11658 07/20/02 05:52 AM
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Ken,

Is it possible for you to disconnect the underground feeder at both ends and do a megger test on it?

#11659 07/20/02 10:17 AM
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I'm wondering if the 'leakage' could be detected with the circuit on and everything being off out at the Dock (or disconnected at that end) by using a milliAmmeter?

Bill


Bill
#11660 07/20/02 04:09 PM
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Bill,

The only problem I see with that is that by using AC you're going to read some current due to the capacitance of the cable (e.g. with 0.1uF you would expect to see about 4.5mA anyway) and that would mask any leakage due to bad insulation.

With a DC insulation test, the capacitance won't be a problem.


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