Voltage in the aquarium

[bjkramer]

I thought I felt a shock (but have neuropathy so it could just be my nerves) when I stuck my hand in my tank.

So I got out the meter, one end in the ground, the other in the tank.

With everything on measured 30-40 volts.

Turned off the powerheads (4 hydors) and it went down to about 10 volts.

With 1 item at a time, it never went below 3...most of the time 7 or 8 volts.

What do the results mean? What should I do?

 

[A.T.T.R]

could be induction.
could be a tiny crack in a wire

 

[Quinzico]

Hi,

that's residual electricity (from several sources). The best way to remove it is to buy a grounding probe. It's a titanium probe that you put on water (SUMP) and connect it the ground pin of any wall connector (ground pin).

 

[tmz]

I always get 2 or 3 volts when I use a volt meter. That's normal for an aquaium and has nothing to do with faulty appliances. The amount you are getting is high at 7 or 8 and may be residual from the appliance problems and would likely be lowered with a grounding probe.

However, a caveat is needed . A grounding probe without a gfci will turn any stray voltage(which is only potential current and as such harmless until it finds a ground) in your tank into current(amperes) which will pass through organisms in the tank harming them and you if you put your hand in there and are grounded. The only way to protect yourself and your tank inhabitants from stray current is is with a gfci. When more current goes out than returns through the gfci it trips effectively pulling the plug.
Stray voltage will disappear from the meter when a grounding probe is introduced but if there is still a leaky appliance the voltage will simply become amperage which doesn't show on a volt meter and is very harmful.

 

[lilmonster]

I had stray electrical once, killed all my fish, found that the seal had cracked on the heater and it was shorting into the water.

 

[Quinzico]

<a href=showthread.php?s=&postid=13467010#post13467010 target=_blank>Originally posted</a> by tmz
A grounding probe without a gfci will turn any stray voltage(which is only potential current and as such harmless until it finds a ground) in your tank into current(amperes) which will pass through organisms in the tank harming them and you if you put your hand in there and are grounded. The only way to protect yourself and your tank inhabitants from stray current is is with a gfci. When more current goes out than returns through the gfci it trips effectively pulling the plug.
Stray voltage will disappear from the meter when a grounding probe is introduced but if there is still a leaky appliance the voltage will simply become amperage which doesn't show on a volt meter and is very harmful.

It is correct, but all houses have a gfci, right?! In Portugal, every house is obliged to have one! If anything happens, the electricity is shutoff in the whole house.

 

[lilmonster]

Unfortunatly, most older houses here Don't have GFCI outlets, (my house was built in 1020)

 

[m2434]

Hey deja vu, I just posted this response in another thread
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1484100

The magnets in the pump are inducing electricity (you could think of this as generating electricity).

See here; due to the nature of salt water, you can think of salt water as the wire:
http://micro.magnet.fsu.edu/electromag/java/faraday2/

The electricity however has no where to go and there is no current, until you put your hand in or add a grounding probe.

Therefore it is highly unlikely that this is detrimental to your livestock, UNLESS you add a grounding probe. If a peice of equipment should fail, this would be bad. However this is a different scenario and a grounding probe may be helpful, but also, may just mask the problem.

Intresting reefkeeping article in HLLE from Reefkeeping mag - talks breifly about grounding probes:
http://reefkeeping.com/issues/2005-06/sp/index.php