Backyard Aquaponics
A place to discuss aquaponics

How would I go about checking to see if my pump is trying to kill me?
My house has an RCD (?) so I'd assumed it would trip if there was a problem. Now I think it would only trip if the current is earthed well, through something like my body...
I finished work early today and decided to check out the system (as you do).
When I put my hand into the FT to pick up the pump to clean the intake, a small cut on a finger tingled in a suspicious way.
So I looked for more scrapes on my hands and had a healing abrasion on a knuckle so I gingerly dipped it in too and now I'm pretty certain the pump has an electrical leakage problem.
Any ideas on how I can confirm this?
Maybe it's just salt on a cut but I've been in Moreton Bay a few times lately and had no such problems.
I really need to find out what the go is here, before I set up the system I was thinking I should shut the pump down before I fiddle with anything in the FT. Now that seems like a good idea again. Also concerned the cage might become live. Not a good scene at all. It's one thing to accidentally get killed myself but I have nephews and nieces to worry about too.
Really need to confirm if this is a problem quickly.

When I bought the system it had been decommissioned for some time and the pump was home to quite a few ants, I'm now thinking they may have chewed through some electrical insulation?
This is a hassle I don't really need, had too many short days at work to buy another bloody pump.

Oh well, in the bin it goes.
sigh

Better to be safe than dead, a small discharge now could be a major one in a short time.

Yeah that's what I reckon too.
Was pretty fool hardy of me to test it a second time when I started to suspect what was going on.

A volt meter/multimeter will tell you what sort of voltage there is- just measure between water and ground. With a bit of salt in the water, you'd only need 12V or less to be able to feel it in a wound. Ground any metal objects near the water to be safe- the RCD will protect you if the current is leaking to earth.

RCDs will not protect you if you grab active and neutral, and you're not earthed.

If you can dismantle the pump you may be able to locate the problem, if not, then throwing it away as you did, is the best move.

Thanks for your thoughts Gunagulla, I think I might add an earth strap or two between the GB and the FT cages and I'm pretty sure the house earth spike is near the system so I'll either attach to that or hammer another one into the ground beside the system to be sure. Probably unnecessary but worth the peace of mind for the small cost.
Off to buy a replacement pump now.
Pretty annoying, I had a spare pump for backup that came with the system but since it was also an ant nest it'll have to be binned too.
I called a sparky to see if it was worth trying to change the power cord or try to salvage it and he said it wasn't worth the risk since they are a sealed unit. Probably be cheaper to replace it than to attempt a repair anyway.
And I shouldn't complain since I'm still breathing.

Ive had this happen to me before, also have read of others on the forum. In my case, I was sometimes getting similar tingles in cuts when in the shower so put it down to bad house earthing.

A friend's garden tap did the same thing, his father worked for SEQEB (now energex) and he didn't care but it was disturbing anyway.
The new pump is in and the tingling has stopped so I'll definitely blame the pump and throw it in the bin. I'll assume the backup pump is in the same condition, since it was also an ant farm and turf it too. At least the new one is identical to my old 'backup' one so I can keep the impeller as a future spare part.
Really hate throwing away things that work but since it's probably now dangerous it'll have to go.
Interestingly the instructions that came with the new pump do say to unplug it before going near the pond.
I'm sure it's only a disclaimer 'just in case' but I might just do that. Probably forget to turn it back on one day too and lose all the fish. One more thing to forget although if I hang the power cord on the back door handle I should be reminded to turn it back on.

Don't ditch the pump necessarily....

This has come up many times before. You really need to get an electrician to come and check your house wiring, for memory it's something to do with poor earthing within the house wiring. I asked electrician friends about it years ago and their suggestion was to GET A SPARKY, and that the pump wasn;t the cause of the problem, but rather a symptom...

Someone here had the same problem with one of our pumps in his system, I tried it in our systems, no problems at all... From memory the new pump we gave him did the same thing, a different brand of pump didn't do it. I think someone may have said it was perhaps because some pumps had earth wires back to the socket while others didn't..

I'll follow your advice EB and get a sparky I know from site work to check the place out but it has given me another thought.
Since I can screw in a fitting and use the pumps outside the FT (sucking water through a pipe - not submerged) I'll keep them as emergency backup pumps.
The way I see it, since they are magnetic driven and no water actually contacts the electrical side unless they are submerged and have faulty insulation then it should be safe to use them that way.
The motor side of the pump has to have some kind of water leak I'm sure but I don't see how that can be an issue if the impeller and pump side is the only thing getting wet. Short term emergency use only, and I'll use the one with the known issue as a last resort only. A backup to the backup so to speak.
Hoarder that I am...

(Just to qualify my thoughts - I'll see what Old Mate Sparky thinks about it, just to be safe.
Also thinking that I can test the 'pump' side for any unlikely leaks by screwing in the fittings and putting something like a blown up balloon on each one to see if any pressurised air leaks out through a crack in the housing into the motor side? Perhaps that is a bit more dodgy than bodgey but I'll give it a go and again get old mate's opinion on it. Pretty sure he'll look at me like I'm a loon though...)

Had the exact same thing happen to me yesterday Bodgy, dipped the pool vacuum net into the AP sump and got a surprising light sting on a cut on my finger. Thanks for the all the info guys!!!

Hello Bodgy, I too had to fix the same problem.

The reason for the tingle is using AC with an extention cord to an ungrounded tank.

AC current induces a voltage not only into the rottor but into the motor casing as well.
The ground wire will bleed off this voltage well enough to satisfy the circuit breaker.

But the breaker is there to protect the wire,, not you.

What I did was to bury a ground wire all the way around my system and especially
where I stand while cleaning filters. Then I hung a 2ft square stainless plate inside the tank
and grounded all metal to this grid.

I have a 1000 gal plastic FT with four pumps for this and that. two of them are two wire
submersables The manufacturer says they are safe; but I was raised by an electriction father
and worked in the trade 40 years. Been zapped many, many times inspite of all my training
and experience. So, even with my ground grid, I still disconnect all power before I clean filters.

So, thank you for posting this topic; it is an issue that I have delt with often.


May all you fish get fat..... Daucie

I remember you mentioning that in a thread from quite a while ago, now that you mention it Daucie Rose.
The ground wire that you used, is it just an uninsulated copper wire? I'm pretty keen to follow your lead (pun unintended...) and earth the hell out of the system now.
Thanks for all the advice everyone, I did ask a couple of young sparkies at work today what they thought and they said the original pump should be alright to use outside the FT. So I'm not too concerned keeping them as backups in case of future pump failures. I'll be slightly sus of them but only use them short term in emergencies and switch off before touching anything.
I hope to get a few years out of the new pump and have the spare impeller now so it shouldn't be an issue anyway. (touch wood...)

Just make sure it isn't wet and connected to the active wire