Another stray voltage thread

[Claus84]

Hi all,

Apologies as I know there have been many threads on the topic but after reading through a lot of them i'm still trying to get my head around some things. I have noticed a slight tingling on a cut on my hand when putting my hand in one of my tanks so I decided to test the voltage and got a total reading of c.65 volts. I tested each bit of kit individually in situ and got the following readings:

Is it possible that a reading this high is just induced voltage? Is there a way to test whether the voltage is from a leak or induced, I'd read something re using an analog voltmeter instead of digi?

I though it might be an old pump running my UV but this only added a couple of volts in total. As a side note I originally wanted to test the kit individually in a bucket of tank water but I was getting crazy readings compared to the in-tank readings (70v for a pump that was giving off 5v when in the tank), could this be a false reading due to the proximity of the test probe to the pump? I have binned that pump anyway to be safe as it was fairly old.

I'm in the UK so its 240v over here and the circuits are protected by a 30mA RCD (which I believe is the same thing as the GFCI I have been reading so much about). The tanks are a 90g and 55g FOWLR with a shared sump and the fish aren't showing any symptoms or signs of distress.

I don't have a ground probe, for no reason other than I have never had cause to think about adding one until now, I can add one if needed but would also like to address the root of the issue (assuming the above is in fact an issue).

Thanks in advance

Nick

 

[fishguy242]

hi,i can only help you with yes ground probes !! 2nd would be check each piece of equip 1 by 1 see which one does not make your finger tingle,start with heaters

 

[Claus84]

hi,i can only help you with yes ground probes !! 2nd would be check each piece of equip 1 by 1 see which one does not make your finger tingle,start with heaters

Unfortunately no tingle now but I think that's because my tiny cut has healed!

 

[fishguy242]

can peel back cuticle will tingle,but lets not get shocked here ,wait for an expert @Brew12 #reefsquad

 

[Claus84]

can peel back cuticle will tingle,but lets not get shocked here ,wait for an expert @Brew12 #reefsquad

Haha yeah that seems like a wiser choice!

 

[thewire]

Get a multimeter and put the ground probe in your ground outlet and put the read in the aquarium. Your reading should be zero V. If there is reading, Then test each device individually to determine which device is faulty.

 

[Claus84]

Get a multimeter and put the ground probe in your ground outlet and put the read in the aquarium. Your reading should be zero V. If there is reading, Then test each device individually to determine which device is faulty.

That's what I did to get the readings in the first post

 

[ksed]

@Brew12 is the expert.

 

[Paul B]

Is it possible that a reading this high is just induced voltage?

Yes is is guaranteed. If it were real current it would read about 110 volts. (In the US, 240 where you live) Don't worry about it. Go out for dinner and have the linguine and clams. Have some merlot.

(master electrician 50 years)

 

[Brew12]

can peel back cuticle will tingle,but lets not get shocked here ,wait for an expert @Brew12 #reefsquad

@Brew12 is the expert.

Hey guys, thanks for the invite!

Is it possible that a reading this high is just induced voltage?

Yes, I suspect it is just induced voltage. Especially since no single piece of kit has a high reading.

Is there a way to test whether the voltage is from a leak or induced, I'd read something re using an analog voltmeter instead of digi?

You have read correctly, many wise electricians use analog voltmeters instead of digital to determine if a voltage is induced. Induced voltages normally have very low power available. Even the small amount of current through an analog meter causes the voltage to drop to near nothing. It's much like a ground probe with a moderate resistance. Digital meters draw almost no current so the voltage stays high even if induced.

I'm in the UK so its 240v over here and the circuits are protected by a 30mA RCD (which I believe is the same thing as the GFCI I have been reading so much about).

Yes, and RCD is the same as a GFCI. One of the big differences is that our GFCI's trip at 5mA instead of 30mA. Otherwise, they are very similar.

I don't have a ground probe, for no reason other than I have never had cause to think about adding one until now, I can add one if needed but would also like to address the root of the issue (assuming the above is in fact an issue).

This is going to be the easiest way for you to determine if it is induced. If you put in a ground probe and the RCD trips, it is a fault voltage. If you put in the ground probe and the RCD doesn't trip, it is induced. It should also stop the tingling when you have a small cut.

 

[Paul B]

You have read correctly, many wise electricians use analog voltmeters instead of digital to determine if a voltage is induced. Induced voltages normally have very low power available.

True, I am wise and old and thats what I do. Digital voltmeters are for Sissies.
Go to dinner.
Hi Brew

 

[Brew12]

True, I am wise and old and thats what I do. Digital voltmeters are for Sissies.
Go to dinner.
Hi Brew

Hi Paul! Always a pleasure seeing you help in these threads.

 

[Claus84]

Yes is is guaranteed. If it were real current it would read about 110 volts. (In the US, 240 where you live) Don't worry about it. Go out for dinner and have the linguine and clams. Have some merlot.

(master electrician 50 years)

Hey guys, thanks for the invite!

Yes, I suspect it is just induced voltage. Especially since no single piece of kit has a high reading.

You have read correctly, many wise electricians use analog voltmeters instead of digital to determine if a voltage is induced. Induced voltages normally have very low power available. Even the small amount of current through an analog meter causes the voltage to drop to near nothing. It's much like a ground probe with a moderate resistance. Digital meters draw almost no current so the voltage stays high even if induced.

Yes, and RCD is the same as a GFCI. One of the big differences is that our GFCI's trip at 5mA instead of 30mA. Otherwise, they are very similar.

This is going to be the easiest way for you to determine if it is induced. If you put in a ground probe and the RCD trips, it is a fault voltage. If you put in the ground probe and the RCD doesn't trip, it is induced. It should also stop the tingling when you have a small cut.

Awesome, I'll pick up a grounding probe and see if I can find an analog meter too, might come in handy in the future.

Thanks for your help and the quick responses, much appreciated.

 

[Claus84]

So my grounding probe is now installed and i'm waiting on my analogue meter turning up in the post.

So with probe installed I stuck my hand in the tank to feed today and got that tingle again in a small cut. This has me a little confused!

The tank is in my garage which is bare concrete and I have noticed that when i'm wearing my fairly old and worn pair of vans I feel the tingle but if i'm wearing thick soled boots I get nothing. Presumably my vans don't do a great job of insulating me but surely there would be more resistance through me than through a grounding probe (even with dodgy footwear)?

The probe is plugged into a 4 way extension lead and I also tried it directly plugged into the wall, I figured it wouldn't really matter either way and I got the zap both ways.

Does this sound normal?

THanks

Nick

 

[Paul B]

Yes it sounds normal. If you install a ground probe, like you should the same voltage, weather it be induced or anything else will still go through the probe, and your cut.

It is to complicated for here unless Brew wants to explain it but your finger and the ground probe makes a parallel circuit and the same voltage will go through both.

If it was real voltage, we wouldn't be having this discussion because you would have been thrown across the room into your bicycle.
As an electrician I have experienced full voltage going through me more times than I care to remember. What you have is nothing. Put a band aid on your cut and forget about it.

 

[Brew12]

So my grounding probe is now installed and i'm waiting on my analogue meter turning up in the post.

So with probe installed I stuck my hand in the tank to feed today and got that tingle again in a small cut. This has me a little confused!

The tank is in my garage which is bare concrete and I have noticed that when i'm wearing my fairly old and worn pair of vans I feel the tingle but if i'm wearing thick soled boots I get nothing. Presumably my vans don't do a great job of insulating me but surely there would be more resistance through me than through a grounding probe (even with dodgy footwear)?

The probe is plugged into a 4 way extension lead and I also tried it directly plugged into the wall, I figured it wouldn't really matter either way and I got the zap both ways.

Does this sound normal?

THanks

Nick

It doesn't take a whole lot to insulate someone from 120V or 240V. Look at the thin piece of plastic that goes around a wire then look at the size of the sole of your shoes.
Is the tingle persistent or does it only last a brief moment?
Something else to think about. The tank may not be the source of the voltage. It may be the path to ground that is allowing current flow.

If it was real voltage, we wouldn't be having this discussion because you would have been thrown across the room into your bicycle.

I generally agree with this, but if there is a high resistance fault it can have limited current. Granted, those current limited faults are pretty rare in the hobby.

 

[Claus84]

It doesn't take a whole lot to insulate someone from 120V or 240V. Look at the thin piece of plastic that goes around a wire then look at the size of the sole of your shoes.
Is the tingle persistent or does it only last a brief moment?
Something else to think about. The tank may not be the source of the voltage. It may be the path to ground that is allowing current flow.

I generally agree with this, but if there is a high resistance fault it can have limited current. Granted, those current limited faults are pretty rare in the hobby.

It seems fairly persistent but i'll double check when I have access to the tank tomorrow. There are no other electrics near the tank, except for the tank equipment itself but of the non-submerged kit I guess my EBAY LED's could be one of the most likely potential sources, I'll do a test with them on and off.

If its just something I have to put up with that's fine as the tingle doesn't really bother me, aside from making me concerned it might be indicative of a larger problem or may be having an impact on my fish.

Thanks

 

[Claus84]

My analog multimeter finally arrived, i'm getting a reading between 30-40v with or without the grounding probe plugged in. 0 amps though again with or without the grounding probe installed.

I understand that its induced voltage and nothing to be too concerned about but I've read a few threads suggesting that with a probe installed the volt reading should be at or near to zero, should that be the case if the probe is functioning correctly?

 

[Paul B]

It's fine, don't worry about it.

 

[Brew12]

My analog multimeter finally arrived, i'm getting a reading between 30-40v with or without the grounding probe plugged in. 0 amps though again with or without the grounding probe installed.

I understand that its induced voltage and nothing to be too concerned about but I've read a few threads suggesting that with a probe installed the volt reading should be at or near to zero, should that be the case if the probe is functioning correctly?

You have something interesting going on but I'm not sure what it is. The ground probe should reduce all voltage to zero, induced or fault.
With an analog meter, induced voltage should read some voltage for a fault and zero for an induced voltage regardless of what the ground probe is doing.
Where are you putting the meter probes when you are doing your measurements?