How do you test for stray voltage?

[SallyWho]

What kind of tool/device/magic wand do I need to test for stray voltage in my tank? For about a week any time I touch the water, it feels like a wasp sting. I thought it was just the saltwater getting into in hangnails and nicks from yard work, until I had done a water change and touched the waste water in a bucket. No zing from the bucket water! So maybe there's something electrical going on in the tank? My tank IS on a GFCI outlet and on its own dedicated circuit. The fish seem fine, some of the corals are struggling but I figured it was because I fell behind on water changes. Could stray voltage irritate coral? I don't have time today, but is the common method just to unplug one thing at a time until I don't get the zing anymore? Thanks!

 

[KrisReef]

That "Wasp sting" is the only way I know how to test. When you feel it, there is stray voltage present.

Unplug things one by one, until the zing stops, the last thing that is unplugged and stops the zing, usually is the problem. Leave it unplugged, replug the others (if there were some) and if they don't restart the zing, you have isolated the offender.

I don't know how to use a voltage meter, but for goodness sake be careful cause these things kill people.

 

[SallyWho]

That "Wasp sting" is the only way I know how to test. When you feel it, there is stray voltage present.

Unplug things one by one, until the zing stops, the last thing that is unplugged and stops the zing, usually is the problem. Leave it unplugged, replug the others (if there were some) and if they don't restart the zing, you have isolated the offender.

I don't know how to use a voltage meter, but for goodness sake be careful cause these things kill people.

....it can WHAT. I know things like shorted circuits, non-GFCI outlets that get wet, or standing in water while plugging things in can electrocute someone, but just some stray voltage?? For what it's worth, it's only a "jerk my hand back" level sting and there's no pain/tingling/bad feelings as soon as I'm no longer in contact.

 

[helmsreef]

Use a multimeter on AC and test

 

[Privateye]

Your finger is enough of a test - the precise voltage won't tell you anything useful.

It's time to start looking for the culprit. Heaters are a common offender, and salt creep on a light fixture is one I've encountered a few times too. I've seen it less-often with pumps, but depending on the style those could be possibilities too.

Usually if it's the UV sterilizer you will know it. I once stuck my hand in a sump where (apparently) the UV seals had been compromised. The next thing I knew I was lying on my back. Those transformers tend to boost the voltage to nearly 400V.

 

[KrisReef]

AI Overview



While voltage is often the most noticeable factor, the danger of an electrical shock is determined by the amount of current that passes through the body. Water is a highly effective conductor of electricity, especially saltwater, which means that even relatively low levels of stray voltage in an aquarium can present a serious risk of injury or electrocution if a person becomes part of the electrical circuit.

Stray voltage typically occurs when submerged equipment, such as heaters or powerheads, develops a crack or seal failure. A dangerous situation can arise if a person's hand is in the water while another part of their body is in contact with a grounded surface, such as a concrete floor or metal stand, allowing electricity to flow through the body to reach the ground.

 

[Mark Goode]

The stray voltage is not usually a short circuit or current leak - it's induced voltage in the water from the changing magnetic field generated by the pumps.

 

[Reefer Matt]

Use a multumeter or voltmeter set to ac voltage. Stick the negative probe into a ground receptacle in a nearby electrical outlet, and the red probe tip in the tank water surface. Read the voltage. If the voltage is the same as house current, that is a short and very dangerous. Unplug things one at a time until voltage on the meter drops. Then replace the equipment, which is usually the heater or other a/c equipment that doesn’t have a controller.

 

[KrisReef]

Use a multumeter or voltmeter set to ac voltage. Stick the negative probe into a ground receptacle in a nearby electrical outlet, and the red probe tip in the tank water surface. Read the voltage. If the voltage is the same as house current, that is a short and very dangerous. Unplug things one at a time until voltage on the meter drops. Then replace the equipment, which is usually the heater or other a/c equipment that doesn’t have a controller.

This is the safe way to use a meter instead of your body, with the plus that it gives you a number instead of a shock.

 

[SallyWho]

Okay, so I went to Harbor Freight and got a little multimeter. Obsessively read the directions and google to make sure I didn't accidentally killyself sticking probes in things....and zero volts detected. Black probe was in the ground hole of a nearby outlet and red probe was in the tank. I stuck my hand in the water and there was no zap! I'll check again at feeding time- the scientist in me says I must test it at the same time of day I've been zapped for the past week- but this was not what I was expecting! Neato little mystery!

 

[KrisReef]

What do you have on a timer?
or default to the heater (they power on and off!)

 

[commod0re]

heater should always be the first suspect, it’s the most likely offender

 

[SallyWho]

What do you have on a timer?
or default to the heater (they power on and off!)

The lights are programmed, and the heaters are on my old Apex. Not much use for the heaters currently, since it's hotter than a dragon's armpit outside, and my electric company just jacked up the rates again so my thermostat stays at 76⁰. The lights are suspended from the ceiling and have no contact with the tank though, so I doubt they're the problem? In a couple of hours, I'll dip my hand in again at feeding time and see what happens!

 

[SallyWho]

Nothing happened at feeding time! No zaps or nothin'! This is the equivalent of taking my car to the shop and it refusing to make the scary noise for the mechanic. Thanks for all the advice, guys! If the zaps return, I have a better idea what to do about it!

 

[KrisReef]

Nothing happened at feeding time! No zaps or nothin'! This is the equivalent of taking my car to the shop and it refusing to make the scary noise for the mechanic. Thanks for all the advice, guys! If the zaps return, I have a better idea what to do about it!

I would encourage you to exercise voltaic caution whenever you are working around your tank that has power cords in and around it. Keep your body isolated from ground and gently enter the water using the back of your hand to check for voltage leaks (reflexes will knock you back) or the new meter.

I am glad to read this thread, and to not be reading about another reefer that can’t post anything anymore, after a mishap.