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Old 08/06/2018, 11:29 AM   #1
Aquavaj
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Stray voltage?

Got zapped pretty good last night when I was standing on damp carpet (made a ATO booboo) and brushed against the metal light hangers. Felt like touching the spark plug on a running lawn mower. Doesn't happen if I stand on dry carpet.

The hangers are screwed onto the wooden backboard of the stand so I don't know how electricity is flowing into them. If I use a volt meter and test it across the hanger and tank water I get 12v AC. Things in the tank that are on AC is the return pump, heater and skimmer pump.


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Old 08/06/2018, 12:59 PM   #2
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Heater is the most likely culprit, but it could be anything. Unplug each one while testing to see which device to replace.

GFCIs are a great invention, by the way.


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Old 08/06/2018, 01:30 PM   #3
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Pumps or heater. It might be a shocking experience but you can pull one out at a time and see if you get zapped.


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Old 08/07/2018, 05:43 AM   #4
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Quote:
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It might be a shocking experience but you can pull one out at a time and see if you get zapped.



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Old 08/07/2018, 06:44 AM   #5
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Use a GFCI receptacle and Grounding probe to find the culprit.


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Old 08/07/2018, 10:11 AM   #6
Aquavaj
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Quote:
Originally Posted by nereefpat View Post
Heater is the most likely culprit, but it could be anything. Unplug each one while testing to see which device to replace.

GFCIs are a great invention, by the way.
It's probably either the return pump or skimmer pump. The heater is on the Apex and was not on at the time. Haven't had a chance to test to determine which one but I'm looking into getting a grounding probe and replacing the outlet with a GFCI.


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Old 08/07/2018, 11:31 AM   #7
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Note: Do NOT use a ground probe without a GFCI..
And make sure that all submerged line powered equipment is on that GFCI..

With many devices being DC now the need for GFCI isn't what it was before..
There is no need to put DC powerheads or return pumps on GFCI..
Only direct line powered (120VAC/220VAC) devices need to be on the GFCI..

But it doesn't hurt to put them all on it.. Just not needed..


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Old 08/07/2018, 02:24 PM   #8
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There is no reason to have stray voltage in your tank. Something is leaking voltage and you need to determine what it is and replace it.

I test periodically with a volt meter just to be sure.


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180 gallon, 40 gallon sump, 8 ATI T5's, MTC MVX 36 Skimmer, Apex controller Reef Octopus CaRx

Current Tank Info: 2 Barred Rabbitfish, Red Head, Yellow/Purple, Hoevans, Possum, 2 Leopard Wrasses, Kole, Purple & Atlantic Blue Tangs, Matted Filefish, 2 Percula Clown, 4 PJ Cardinals, Swallowtail Angel
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Old 08/07/2018, 03:25 PM   #9
Aquavaj
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Quote:
Originally Posted by mcgyvr View Post
Note: Do NOT use a ground probe without a GFCI..
And make sure that all submerged line powered equipment is on that GFCI..

With many devices being DC now the need for GFCI isn't what it was before..
There is no need to put DC powerheads or return pumps on GFCI..
Only direct line powered (120VAC/220VAC) devices need to be on the GFCI..

But it doesn't hurt to put them all on it.. Just not needed..
Why is a gfci required with a ground probe? Also, are inline gfci ok or the outlet type is better suited?


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Old 08/07/2018, 03:29 PM   #10
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There is no reason to have stray voltage in your tank. Something is leaking voltage and you need to determine what it is and replace it.

I test periodically with a volt meter just to be sure.
I am wondering where the voltage is coming from too when the hangers have no direct contact with the water.


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Old 08/07/2018, 03:38 PM   #11
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I am wondering where the voltage is coming from too when the hangers have no direct contact with the water.
I messed up. I thought you got zapped from touching water in the tank. What are the hangers used for? Lights? If so, what type?


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180 gallon, 40 gallon sump, 8 ATI T5's, MTC MVX 36 Skimmer, Apex controller Reef Octopus CaRx

Current Tank Info: 2 Barred Rabbitfish, Red Head, Yellow/Purple, Hoevans, Possum, 2 Leopard Wrasses, Kole, Purple & Atlantic Blue Tangs, Matted Filefish, 2 Percula Clown, 4 PJ Cardinals, Swallowtail Angel
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Old 08/07/2018, 04:44 PM   #12
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T5/MH fixture. There's 2 brackets that slide on and hung by plastic shielded metal wires. Light fixture casing looks to be powdered coated as well as the brackets but not really sure how thick the powder coating is. All plugs are 3 prong.

I'm going to do some more testing tonight with a volt meter. I was showing 12v when I tested across the hanger and tank water after I got shocked.


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Old 08/08/2018, 06:02 AM   #13
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Why is a gfci required with a ground probe? Also, are inline gfci ok or the outlet type is better suited?
GFCI receptacles require 4 to 6 milli-amps to operate. The grounding probe provides the grounding path, versus your body. Many times we are wearing shoes, standing on carpet, or our thick skin which provides some resistance and therefore may not get to 6 milli-amps, but maybe only 3 which is still a pretty good jolt but will not trip the gfci. Before using a grounding probe you will need to make sure your wiring is up to date and your receptacles are grounded with a ground wire. I have gone to a friends home where someone changed all the receptacles to 3 wire grounding, even thought there was no grounding wire. His stealth heaters provided plenty of punch of current because his grounding probe was worthless. And last but not least Voltage Has No Power, it is the current that is shocking you so change the name to stray current. The best way to describe this is a water pump is voltage, and current is the water. You can have all the voltage in the world, but without current it is worthless. AC pumps spinning in water create stray voltage, so do open lamps to water, but without current it is worthless and not harmful to humans. I have tested a system with only two volts, but the current was over the top and the shock was painful.
In this case like many others, the light fixture / support wires just provided a great grounding path to complete the circuit.


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Old 08/08/2018, 09:41 AM   #14
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Quote:
Originally Posted by Aquavaj View Post
T5/MH fixture. There's 2 brackets that slide on and hung by plastic shielded metal wires. Light fixture casing looks to be powdered coated as well as the brackets but not really sure how thick the powder coating is. All plugs are 3 prong.

I'm going to do some more testing tonight with a volt meter. I was showing 12v when I tested across the hanger and tank water after I got shocked.
You completed a circuit between the metal in the lamp enclosure and the ground. If the enclosure had been grounded (vs isolated by wood) you would not have been shocked, but the GFCI the lights are plugged in to would have tripped.

This is a classic example of why metal enclosures are supposed to be grounded - so when there's a fault with the equipment inside them, current flows to ground instead of potentially flowing through a grounded human who happens to touch the enclosure. You aren't getting shocked when the carpet is dry because there's no path to ground then. Measuring voltage between the tank water and the light enclosure is essentially meaningless, by the way.

In summary: your lights are faulty. And not properly grounded. And they should be on GFCI if they aren't.


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Old 08/08/2018, 03:20 PM   #15
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In summary: your lights are faulty. And not properly grounded. And they should be on GFCI if they aren't.
Thats an assumption that I wouldn't make just yet..
The carpet could have been the higher potential and the light the ground..


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Old 08/08/2018, 03:31 PM   #16
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Okay, fine. Check the wiring in your carpet for any damage or frayed insulation. If you find nothing wrong, THEN check the light fixture.


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Old 08/08/2018, 05:57 PM   #17
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I usually only lurk around here anymore, but this made me physically laugh out loud. Thank you for that.


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Okay, fine. Check the wiring in your carpet for any damage or frayed insulation. If you find nothing wrong, THEN check the light fixture.



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Old 08/09/2018, 05:54 AM   #18
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Okay, fine. Check the wiring in your carpet for any damage or frayed insulation. If you find nothing wrong, THEN check the light fixture.
It wasn't clear if the ato failure was exposing the carpet to tank water at the time they were standing on it..
I envision them having ato water poured on them and freaking out hitting the light and voila..
Could just be the ato pump is the faulty equipment..

The 12V potential measured between light and tank is probably just radiated from either the bulbs or pumps or whatever and not indicative of a fault..

A simple check from light enclosure to outlet ground will confirm any potential fault there..


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Old 08/09/2018, 01:54 PM   #19
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The interesting parts of this for me are the reference to a spark plug and the mechanics of whatís going on.

Referring to a spark plug, makes me think it was the ballast leads that did the shocking and not the 120 feeding the fixture? Iím fortunate enough to have been hit by those three sources. 120 feels very different, much slower and a deeper feeling.

The other part, is. Standing on carpet means a wood or concrete substrate Which, last time I checked doesnít conduct electricity. So with it being wet.....where is that connecting to ground allowing the current to flow? They stated they can touch the fixture on dry carpet no problem.


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Old 08/09/2018, 03:37 PM   #20
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It is amazing how many emails or post I have answered that started with my "Light is Shocking Me", when after investigation the light was only providing a grounding point of the circuit. And in this case where the sump had run over and now the carpet was wet, the current in the tank had the potential to make its way to the wet carpet with the padding still proving insulation. When the member touched the light it provided the ground he needed to get shocked. No different than if their hand was in the tank or sump when they touched the light. Hopefully we can get an update?


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