Stray current found in return pump (About 1V AC)

[Scoot]

I noticed today when I reached into the tank to adjust a power head, a zap - not severe, but it stung. I noticed it was affected just on a small cut on my thumb, so I reached back in, and the sting returned.

Not sure if it was stray voltage, or the salt water, I put some tank water in a cup, and stuck my thumb in. Nothing.

Back to the tank. Sting.

I started unplugging equipment, one thing at a time.

Thumb in tank. Sting. Sting. Sting.

I ended up at my main return pump. Unplugged it.

No sting.

Plugged it back in. Zap.

So I immediately yanked a larger powerhead from the tank, put in the barbed hose adapter, and put it in my sump to work as a return pump. Meanwhile, there was a tad bit of overflow in the cabinet (working on that now).

So, I put the old pump in a bucket, covered it with water, and no zap. Coincidence? I don't know. I don't really want to play with it too much, in case the shock gets worse.

I'm one of those people that can feel a really slight electric current. Maybe I'm a superconductor. I don't know. But this was annoying.

How much stray current does it take to start hurting residents? I havent' notice any problems at all, but this had to be enough to start making them uncomfortable...

 

[melosu58]

You might have a problem with that pump as you should not be getting shocked everytime you put your fingers in. How are the fish acting? Do you have a ground probe? I believe you pump either needs cleaning or replacing.

 

[Scoot]

They were fine, except a couple of chromis had been a little jerky today.

No ground probe. I'm going to go find one today.

The pump, I noticed, has a bulge on one side that wasn't there when it was new. It does need cleaing, but that, I wouldn't think, would cause stray current.

And to clarify, I wasn't *really* getting, shocked, but a nice strong stinging senstation on a small cut. Didn't affect the rest of my hand/fingers/etc. But the sting was strong, and the first time I felt it, I jerked my hand so hard, I hit the reflector on my MH's, almost hitting the bulb.


UPDATE

Updated - realized I had a VOM from an earlier hobby.

Am showing, on that pump (in a separate bucket), about one volt of AC.

Is this enough to cause problems for inhabitants? I assume if *I* can feel it, they can too.

 

[melosu58]

They were fine, except a couple of chromis had been a little jerky today


It does need cleaing, but that, I wouldn't think, would cause stray current.

I assume if *I* can feel it, they can too.

Fish will tend to be jerky if current is in the tank. Also a dirty or obstructed pump will draw more power through it causing short or faulty operation causing current to be in tank.

 

[Scoot]

The pump wasn't in need of cleaing that bad, I actually clean them all weekly.

It just needed normal cleaning.

It looks like it overheated at some point, causing the big bulge on the side.

 

[melosu58]

There`s your problem.

 

[afishyonados]

Stray voltage can cause misinformation in the synapses of the brains of inhabitants. It has been shown to lower immune systems and disrupt the appropriate intake of vitamins and nutrients in specimens subjected to it.

The pump overheated, and probably expanded the epoxy enough to expose a wire. Discard and consider an external pump like Iwaki or Blueline. Much less possibility of stray voltage.

 

[Scoot]

Its already in the junk pile. Luckily, I had just received a new pump I was going to use for closed loop circulation. Took 15 seconds to swap it out.

I still feel a tiny bit of a "bite" when I stick that finger with the cut in the water, more troubleshooting to do. I unplugged nearly everything, I think it may be induced current from the MH and PC lights.

 

[roka64]

Go with the titanium probe, you can't go wrong! You are lucky, the current didn't kill your fish, or YOU!

 

[afishyonados]

Keep working on it, for everyone's sake.

 

[ddm_aet]

ground probes are good for protecting you, but all they do is complete the circuit and allow whatevers faulting a way to get to ground. There will still be current running through the tank. Its better to find out what piece of equipment failed and replace it or try to clean it to fix the problem

 

[afishyonados]

Brilliant!

http://www.madisonreef.com/forum/viewtopic.php?t=1416

This is a most eloquent presentation of what ddm_aet is discussing.

 

[melosu58]

Its better to find out what piece of equipment failed and replace it or try to clean it to fix the problem

I couldn`t agree more

 

[Scoot]

Turns out it wasn't the pump.

I was still getting voltage readings in the water.

I have some sort of grounding issue with my outlets - I have an electrician scheduled to come out, but for now I'm using two methods to ground.

One, a titanium grounding probe.

Two, I'm running another lead from the sump, to the carpet. Yes, to the carpet.

Apparently I've got a "loose" ground or something, because everything wants to ground to the floor. I get a reading of around 6V AC by testing from the tank or sump, with the other lead jammed into the carpet. There's nothing when the ground lead goes to a "real" ground, on my power strip or outlet. That means that ground isn't grounded

With my second grounding circuit going from the sump or tank, to the carpet (wedged under the lip of the tank stand), I get zero readings from the tank to any ground.

Yes, this is a mess. Hopefully the electrician will be able to fix.

It's not any one piece of gear. I've unplugged everything, then added stuff back one piece at a time - voltage from tank to ground rises a tiny bit with each piece of gear.

To test my theory:

I take my skimmer pump, put it in a bucket. Test for voltage from the water to the outlet ground - nothing. Test from the water to a damp spot on carpet - I get from 6 to 30V AC. Ouch.

Move this setup to another part of the house - nothing - no voltage detected anywhere.

So basically, I threw my old 575GPH pump away prematurely (even though it was swollen up on one side).