Electrical expert needed...

[SalmonAlley]

Okay,
I've just spent the last two hours checking my tank with a multitester meter, and reading the threads on stray current in the tank.
Yesterday I felt a tingling when I put my hand into the tank...didn't like it very much.

Today I purchased a multitester and tried to isolate where the stray current was coming from.

First off, this thing is a 'Sperry SP-10A' .
Second, it's got several settings, I assumed I wanted the 'ACV' setting (others were DCA, DCV, OHM and B.TEST).

I placed the NEG probe into the ground in a receptacle, and the POS probe into the tank. My initial reading was: 1.4 AC V I then started unplugging equipment. I started with powerheads first, then heaters, then Calc reactor pumps, and main pumps. As I unplugged each piece, the reading climbed. At this point, all that was still running was the lighting. When I shut down the lighting, the levels dropped back to 1 AC V (with nothing at all plugged in).
To be sure I restarted the lights. First the IceCap 660...reading spikes to 4 AC V.
Then Metal Halides (2-250W and 1-400W all on E-ballasts) with the IceCap and reading drops to 3.4 AC V
Finally MH alone- back to 2 AC V.

So...what the heck does this mean? and how do I fix it?

 

[reefNewbie]

Multimeters are usually really jumpy with there readings. I would bet the spikes you are seeing are do to the neg probe connected to the ground wall outlet, where your lights go through. As for why it is reading 1Vac, that may have something to do with the way its grounded as well. If you felt a tingle there is no doubt something is leaking current into your tank. I would take out each piece of equiptment and isolate it in a bucket with water and test each that way.

 

[LA-Lawman]

Yup,

Tony's got it nailed. Isolate each piece in a bucket of water and then test. then buy a ground probe for the tank. I take it your current setup doesnt ahve a GFCI attached.

Let us know what you nailed it down to. Be sure you talk to the manufacter also. they might replace it or offer some assistance with the product.....

 

[deano]

I'm not electrical expert. But here is what is going on. Your lighting is allowing the stray volage into the tank. This happens due to the fact that fluorescent lights produce alot of inductive current across the bulbs. This current can pass to your tank water though salt creep on the wires or if the bulbs ar sitting on a glass top the salt creep builds up and make a good path from the lights to the tank water. Even a small water spill on the glass can cause this.

Now for why it increased as you unpluged things. My guess is these items were allowing a path for electrical current to go to ground which will cancel out the stray voltage. As you unpluged them the ground was taken away increasing the voltage.

How to fix the problem. Clean all electrical wires and connections of salt creep. Remove fluorescent bulbs from sockets and clean the bulbs end to end and the sockets they plug into. Install a ground probe into the tank water and make sure all devices are pluged into a GFCI.

 

[SalmonAlley]

Wow!
Quick and helpful responses! Thanks to everyone who took a moment to do this.

I'd like to add some additional information:
1- All the electical devices (except the Metal Halides) are on GFCI receptacles. In most cases, a power strip is plugged into the GFCI which then feeds 3 or 4 things.

2- My MH are plugged into a 'regular' outlet on a separate circuit temporarily, while I am rewiring. (the rewire hasn't reached the panel box, so I don't think it's a variable here)

3- My MH and Fluorescent bulbs are suspended from the ceiling, the bulbs themselves are about 8" off the water. I don't see any visible salt creep on or near the bulbs or wiring. (not saying it's not there, just that I don't see it)

4- I assume when I test each pump, etc. separately I should NOT use the ground from an outlet on the same circuit as my NEG probe?

Thanks again!
Jeff

 

[steve F]

Hi Everyone,

Yes so far good advice. clean everything up, isolate each peice and try to find out what is causing it.

I for one will not use GCFI's on my system(except my lights). I have installed 5-20A dedicated lines for my new 300g(coming Feb 1st).

Ground Fault Curcuit Interupters will break the power when there is power leaking to the ground. 1-4V will probably not be detected. Most GFCI's are made cheap, I know i've installed hundreds.

GFIC are great for the lights because just in case they fell in. I will use a 20Amp GFCI breaker in the panel and not the recepticale kind. But other than that I don't see a need to have them, because they fail and pop alot more then I'm willing to risk my system with.

Steve

 

[Anonymous]

GFIC are great for the lights because just in case they fell in. But other than that I don't see a need to have them, because they fail and pop alot more then I'm willing to risk my system with.

This is the absolutely the worst advise I have ever seen posted on this board. GFCI saves lives! Plain and simple. If yours are tripping and popping all of the time it is because you have a ground fault. You need to find out what is wrong and fix it! FWIW, my GFCI's have never tripped a single time in the two plus years I have been in this hobby.

Louey

 

[steve F]

Thats not what is was saying.

Once they get older they have a greater possibility of failing. I did not say that they are poping all the time or even at all.

I was saying in general.

Yes they are great for bathrooms or sinks just in case you drop something in.

But put a GFCI on a refrigerator, chiller or freezer or a garage opener once and see what happens. And yes not all the time, but they do fail.

Thats all I was saying

 

[Anonymous]

Ok, I understand where you are coming from. And to clarify my position: Anything that is in the tank, sump, skimmer, etc. or is in reach of the tank, should definatley be on a GFCI. Also, water conducts electricity, so anything plumbed into your system should have GFCI protection. I have never had to use a chiller, so I don't know what kind of problems you may run into with plugging one into a GFCI. The start-up current of the motor may trip a 15 or 20 amp GFCI.

What do folks with chiller do for GFCI protection? I sure I'll need one on my next tank, so I might as well go ahead and find out the solution now.

If your GFCI's are tripping because they are old, replace them. You do need the protection!

Louey