Shocking Tank

Jaco Schoeman

Jaco Schoeman

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Hey Guys

This morning when I fed my Nennie, I felt my water shocking me at the surface. At shocked myself untill my finger went numb just to make sure this is really happening. Basic physics says that if you are barefoot, you are earthed - thus with shoes there is no effect.

I then phoned my dad as he is a electrical expert, and he says that his tank does the same. He asked me if I have a cut on the hand that I used - which I had. He then said that when he puts his other (none cut hand) in the tank - nothing... So I tried again, and still got a shocking experience.

There are only two things electrical in my tank; two powerheads. Immediately after swithing them off, the shock stays, but if I wait a few moments the shock is gone. I then tried to determine which of the two it was.

It seems to be my Seio 820 (dad also has the exact same one?!?!?!?) I know that it has a magnet on the inside that spins. Can this be the cause?

My lifestock all seems 110% fine... Luckily. I am just a bit scared, as this is not really normal. And what if the tank earths on some whay... then bzzzzzzz... and gone are my lifestock.

Please help.
 
its stray voltage, u can use an earth to stop it, earth your stand and one can also earth the water with a stainless steel probe.
 
Thanks dallasg. Dont think its the stand, as there is no current available there. Also there is no cotact between the tank and the stand. Tank is on its polystyrine and then on top of a piece of superwood. Thus I recon it's the water. Does one get a commercial probe like this? Or do you make a DIY probe?
 
Jaco,

You need to find out what the cause of the leakage current is.
Are the plugs all earthed ?
All equipment used in and around the tank must be earthed. This is sometimes quite difficult since most powerheads or pumps use a 2 core supply lead with no earth connection. The main earth connection must be present on the plug/adapter .

Check the plug outlet , multiplug adapter (if you're using one) to ensure the earth connection is solid. It is very possible to get a floating voltage potential in an unearthed or badly earthed system.

Earthing the tank by means of an earth stud/probe will eliminate the schock potential.
However, if it is malfunctioning equipment which is causing the fault , you will still get a circulating current , which will damage the pumps / heaters etc. in the long run.

Hope this makes sense to you :p
 
Jaco Schoeman said:
My lifestock all seems 110% fine... Luckily. I am just a bit scared, as this is not really normal. And what if the tank earths on some whay... then bzzzzzzz... and gone are my lifestock.

Please help.
Click to expand...

Jaco,

In the interim , your livestock will not be affected by the stray voltage. Remember that your tank is isolated from the metal stand by means of polystyrene.

The only reason you got schocked is because you completed the earth path for the current. Current will always look for the fastest , least resistive path to ground.
 
How's your lighting attached to the tank? My nano used to shock me due to my T8 lighting I had in it was not very well insulated. Just a thought.
 
Thank you guys. I will check all of the above. Maybe it is the earth on my wall plug.
 
Apollo said:
Jaco,

All equipment used in and around the tank must be earthed. This is sometimes quite difficult since most powerheads or pumps use a 2 core supply lead with no earth connection. The main earth connection must be present on the plug/adapter .
Click to expand...

Is there a way to earth these appliances that only have live and neutral connections?
 
Mudshark said:
Is there a way to earth these appliances that only have live and neutral connections?
Click to expand...


Mudshark,

It is rather difficult to do unless the device /appliance itself has a metalised casing where you could attach an earth wire to. This would however mean that you need to open the appliance . Not a good idea.:nono:

Most pumps , powerheads etc. have a double insulated casing and electrical system and hence (the manufacturers claim) they don't need an earth wire.

Most of the problems I have picked up on these appliances is when there has been any water ingress into the stator windings . This sometimes happens as a result of wear and tear or manufacturing defects , where the casing is not 100% watertight , especially at the cable gland connection coming out of the pump/powerhead.

You could also have breaks in the cable/power cord , which will normally result in a phase to neutral fault. I't wont neccessarily trip the earth leakage on your main DB , but you will certainly feel the effects when touching the appliance or the water in this case.:p

To protect yourself , the best way is to ensure that the plug point/multi-plug adapter is properly earthed and your wall socket outlet is also properly earthed.
 
Hi guys,
I have found this problem on my tank as well, it is more evident in the sump but I have also found that if I mess any water behind the tank and If I touch this water while standing on the floor bare feet it also shocks me.My tank is an in wall tank so no metal stand.
Cheers
 
Hi Jaco - LOL - have you noticed how MOST cheaper pumps are 220 volt, and do NOT have an earth? Also - have you noticed that you fluorescents (T5's and T8's) do not have an earth wire on the plug?
Where you do think the earth leakage would go to? When the tank is isolation (the glass from the metal stand) - then - any stray voltage caused by the pumps/power-heads, and the fluorescent globes start units, WILL go through your body down to the earth - AND ONLY WHEN YOU ARE BAREFOOT.

This is part of keeping marines.

On the long run, some fish are scusceptible to getting lateral line disease, due to the stray electricity.

Best method to test - is to switch off all pumps and lighting, and then switch these on one-by-one, until you feel the shocking. You can also use a multimetre if you prefer, to test for the current. By earthing the black electrode, and placing the red electrode in the tank's water.
 
Thank you guys. Gheeeee, I didn't think I was the only unluckly sucker who had this issue... Scary thought that we all work with 220V around water, and so many of us get choked by it!!! And yes Jacques, why can't marine equipment manufacturers put earth wire in their products... I mean really... Water + electricity = BZZZZZZZZZ!!!

Anyway, I found MY problem (also after finger testing...:lol:) It was the 15W T8 light that hangs over my DSB / Sump area. I had to improvise quickly when I made it at first, so I basically tied it to a piece of persepcs with cable ties. Although nothing touched the water surface, it had plenty of salt packed around the connection part. The moment I took it away from the water surface... hey presto!!!

So I'm safe for now... Still should earth the tank maybe just to be safe...
 
Had the same problem with salt creep & electricity... and yes, almost shocked myself into another dimension when I modded the hood for the lights.. uhm... it's a wonder the house hasn't burnt down yet because of my electric engineering abilities! [NOT!]
 
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