Stray Voltage, ~54

Akadios · May 3, 2018

So I had a small cut on my thumb while doing a bit of tank maintenance and felt a slight sting. After a bit I figured out it was electricity. When I turn everything off (from the GFCI) it would immediately go away. However I was having trouble pinpointing what equipment it was.

I read a couple threads on the issue, got myself a multi-meter and a outlet tester. The outlets test fine, at the power strip the gfci adapter and the outlet itself. The GFCI was tripped by the outlet testers testing button in addition to its own.

The multimeter read the voltage at ~54 with everything on. The lights all being off yielded no change.

The heater being on/off yielded ~6
Each of my powerheads (4 of them on a wave maker so 2 on at a time) yield ~3.5 each
My Return Pump (Lifeguard 2200) yields ~16
My Media Reactor Pump (MJ1200) yields ~ 5
My Skimmer Eshopps x120 yields ~ 15

I am unsure how to approach this situation

GK3 · May 3, 2018

What units are using, volts, millivolts, gigawatts?

What mode is your multimeter in?

Where are the multimeter probes, the red one in the water and the black one is where?

miPapareef · May 4, 2018

Install a grounding probe.

https://www.bulkreefsupply.com/vertex-titanium-grounding-pole.html

Akadios · May 4, 2018

I'm measuring volts, black in a ground of outlet, red in tank.

What do you mean what mode is it in? It is in AC voltage measurement.

In reference to the grounding probe some people seemed to say they were a bad option. Is there any logic to that?

It doesnt seem like I have much choice without dropping the money for a bunch of DC pumps and such is the grounding probe the best option? Is the grounding probe itself bad for livestock or only if there is an actual short and the gfci doesnt trip?

Thanks for input

Akadios · May 4, 2018

I ordered some grounding probes it was a 2 pack on amazon any reason to use 1 in the sump and 1 in display or not?

I will have new GFCI put in next to the current outlet so the ground can be straight to the wall not though a strip. Any other concerns?

GK3 · May 4, 2018

If you are measuring 54 volts AC stray in your tank, I am not sure how your muscles aren’t seizing and your hair isn’t standing straight up. Using a grounding probe isn’t a great idea without figuring out where the voltage is coming from. Essentially all you are doing is giving it a path to ground. These are a safety tool such that any voltage in the tank will go to ground as opposed to using you as a ground, but you still need to figure out where the voltage is coming from. If that voltage increases, the next time you go to put your hand in your tank, it may jump to you as a ground and you’ll feel more than a tingle.

GK3 · May 4, 2018

Have you tried unplugging devices until that high voltage goes away? You’d then know the cause and he piece of equipment to fix/replace. I’d keep my hands out of the tank until you know the issue.

chipmunkofdoom2 · May 4, 2018

If you are not running a ground probe, some voltage is to be expected. Even properly-functioning equipment in our tanks will create induced voltage. Simply having AC current sources near conductors will generate voltage. A few good posts from @Brew12:

https://www.reef2reef.com/threads/stray-voltage-and-acceptable-levels.291622/page-2#post-3564906
https://www.reef2reef.com/threads/grounding-probes-worth-it.341687/#post-4254592

As to whether 54V is too much, I don't know. It sounds a bit high (20V - 30V seems to be a more common number). But, you also have a lot of equipment running in your tank, which could increase the induced voltage generated. Perhaps @Brew12 can weigh in.

siggy · May 4, 2018

for now until you get the probes just use any wire and plug into the ground prong hole and the other in the tank and see if it trips the gfi

redfishbluefish · May 4, 2018

Induced voltage?

@Brew12 should have some insight.

I'm sure he'll want to know about GFCI and grounding probes.

Brew12 · May 4, 2018

56V does seem a bit high but it is possible. The fact you have a functioning GFCI would tend to make me believe it is an induced voltage.

There are a few ways to check. Can I ask what type of meter you purchased?

Akadios · May 4, 2018

https://www.amazon.com/gp/product/B078JZHN3X/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

Akadios · May 4, 2018

I did each piece of equipment alone which led to the results in the original post. When everything is running together the results are slightly higher than each piece alone, unsure if that is normal.

I have had my hand in the tank and only a sting when i have a cut, much less than say the electric fence on the horse pasture when I was a kid... This leads me to believe that the actual amps are low.

CoralFan1776 · May 4, 2018

Akadios said:
I did each piece of equipment alone which led to the results in the original post. When everything is running together the results are slightly higher than each piece alone, unsure if that is normal.

I have had my hand in the tank and only a sting when i have a cut, much less than say the electric fence on the horse pasture when I was a kid... This leads me to believe that the actual amps are low.

The fact that you feel anything makes me worry that your GFCI isn't working. It should trip before you feel anything.
It's good to have a grounding probe even if you don't leave it in the tank so you have it for trouble shooting.
With the ground probe in the tank, there should be a path to ground for any device and if the device is plugged into the GFCI then it should trip.
The way a GFCI works is it compare the amount of current going through the hot wire to the amount going through the common wire and if they don't match with in some small tolerance, then it trips.
It there is much current at all going to ground (not through the common wire, like you to ground or the ground probe to ground) then it should trip.

Adele · May 4, 2018

This might be a silly question...is the culprit narrowed down to just what equipment is plugged in to the DT area where the appendage is getting zapped? Or are the pumps and heaters that are in the sump suspect too? I have a similar issue in my QT so I was curious if it was something operating just in the tank. You nailed it on the head with the description. I thought I had a cut on my finger where it 'stung'. ;Inpain

WVNed · May 4, 2018

Read the amps. Your meter has a uA range. Start with the A range first though and the red probe wire in the left port on the bottom of the meter. If it reads zero move the probe to the right port and try the mA and uA ranges. Note it says your meter is rated for 800mA max on the right port.

The last time a tank tingled me like that I found a bare wire on a heater where it passed over the rim into the sump.

I read my tank and it shows 32V and 19.2 uA to ground.
A GFI is supposed to trip at 4 to 6mA leakage to ground

Brew12 · May 4, 2018

WVNed said:
Read the amps. Your meter has a uA range. Start with the A range first though and the red probe wire in the left port on the bottom of the meter. If it reads zero move the probe to the right port and try the mA and uA ranges. Note it says your meter is rated for 800mA max on the right port.

The last time a tank tingled me like that I found a bare wire on a heater where it passed over the rim into the sump.

I read my tank and it shows 32V and 19.2 uA to ground.
A GFI is supposed to trip at 4 to 6mA leakage to ground

Agree with this.

Read the Amps from the tank water to ground. If it reads mA or higher, you have an issue with equipment but it will likely trip the GFCI. If you read uA and/or the GFCI does not trip, odds are it is induced.

Akadios · May 4, 2018

I am at work, when I get home I will check the current. I haven't used a multimeter since high school electronics class, So I am 100% okay with a detailed explanation of the use to get these readings you are suggesting.

It seems more likely to be the pumps in the sump, with everything in the sump turned off it reads only 11 volts with the heater and powerheads going which is all that is in the display. The lights including refuge light reads at zero. The pumps in the sump for skimmer and the return pump) both run it up about 16 to 18 volts when either is on. I will pull them out each and check there cords since it was mentioned the bare wire issue.

Thanks for the help

WVNed · May 4, 2018

Here are the directions for the meter you linked.
Read from water to ground

7-3 Measuring DC & AC Current
7-3-1 Connect the black test lead to COM jack and the red to the VΩmA jack for a maximum
600mA current , for a maximum 6A or 10A current, move the red lead to the 10A
jack.

Me
It is standard practice to measure unknown circuits from highest range to lowest range. This hopefully prevents you from smoking the meter and yourself.

7-3-2 Set the rotary switch at the desired “uA” & “mA” & “A” range position, it shows
symbol for testing DC current, if you want to test AC current, push “SELECT” button switch.
7-3-3 Connect test leads in series with the load under measurement.
7-3-4 You can get reading from LCD. The polarity of the red lead connection will be indicated
along with the DC current value.
NOTE:
1.
When the value scale to be measured is unknown beforehand, set the range selector at the
highest position.
2.
When only “OL” is displayed, it indicates over-range situation and the higher range has to be
selected.
3.“” means the socket mA’s maximum current
is 800mA and 10A’s maximum current is 10A,
over 800mA or 10A current can be
protected by the fast fuse.
4. On the 10A range, the measuring time should
be less than 10 seconds to prevent precision
from affecting by circuit heating.
https://images-na.ssl-images-amazon.com/images/I/71zjoMAfHBL.pdf