Electricity in the Tank!

Nitroq2

Nitroq2

New member
Ok folks was just sitting back and relaxing when I heard an alarm from my tank. I jumped up ran in there to find that my sump flood alarm was going off. So then I noticed that my sump lights was out and finally realized that my GFCI Wall outlet was tripped. Humm that should do that so I plugged it back up in 30 seconds it tripped again. Then thinking back to our recent discussion I grabbed my meter and checked it with all off. Got a reading of like .3v then I plugged it back up to get a reading of over 20v wow quickly I unplugged the power heads and that dropped it to 18.7. Then unplugged a heater and it went down to down to 17 unplugged the backup heater and then it went to like 3.7 volts. I unplugged my skimmer now its down to like 1.7 then the main pump and I was back to like .3 again.
Removed the heater and turned every thing back on and I still get about 7.8v. But my GFCI doesn't trip any more, so I am guessing the heater must have dumped more electricity to the tank when it came on and that was tripping the breaker. I guess my question is how much is acceptable? It looks as if every pump or underwater device plugged in bleeds about 1.5 - 2 volts. Also you guys with a meter if you dont mind see what your tank reads and tell me how many devices are under water.
I just used the common ground on one of my wall outlets as the ground. I also tried to ground to a screw in my stand and that gave me half the voltage. I am far from an electrician so don't get technical with me, or you will lose me. As for our question about whether the electricity would travel from the sump to the tank the answer is yes. Even with the pumps off and the overflow drained to the sump, it was still reaching the tank. I am guessing it was traveling the return line which would maintain water.
The good news is I did have a CFCI plug in place or it might not have been good for me or my fishes. Unfortunately the lights are off so all the fish are outta sight, so I wont know until the morning if any livestock was damaged. Another question for you guys and gals especially the ones with the grounding probes. If your tank is reading 0 volts now please disconnect the grounding rod and check it without it. I am curious as to whether that would essentially kill the 8 volts in my tank.
Thanks for your help in advance, and for folks that don't have GFCI get it on your tank you never know when a heater or pump is going to leak electricity in the tank, and without it the damage could be your life.
 
Well one system shows 4.5volts and the other shows 5.7 with my heaters (ground Probes) unplugged. I knew there was always some stray voltage.. Every time I've tested a tank that shocks you it always had over 11 volts. So not sure were exactly the normal mark is.. But I'm pretty sure 20 is bad lol

Interesting.. So by adding a Ground probe you could be causing a path for the current in the tank and cause a problem.. So testing the Voltage in a tank doesn't do that much inless you test it between two points under water and even then it might not be a true reading lol. I still think a ground probe keeps the person a little safer even if it might cause problems with some fish.

On the other hand. I have always been worried about a Ground probe Hiding a leaking powerhead and one day I'd unplug my heater and get Zapped lol. I wonder if a gfci would trip if you had a short and a ground probe in the tank? I might have to test this ;)
 
Gotta love reefing there is never a definitive. LOL Will be watching for your tests, I enjoyed the heat one and this one should be great as well. My question is how do you measure the voltage of two points under water? LOL

Also if you were grounded to a surge strip connected to the GFCI you would think it would trip either the surge strip or GFCI for sure.
 
That Little Tingle

That Little Tingle

I got a real wake up call a couple of weeks back when I got "bit" when I stuck my hand into the tank. (I get bit often but usually by my Tomato Clown).

I plugged and unplugged cords trying to find the source of the "tingle".

I thought it was in one of my pumps but it was in my 3 year old power strip. It had accumulated a real "patina"of salt and was conducting current on the power cord surface(also laden with salt) of one of my submerged pumps.

After cleaning the cord and replacing the strip, everything is working great. Note: the new power strip is outside the cabinet where the humidity is lower.

Goose
 
Well I've did some more reading, and thinking for that matter.. Doesn't matter if its current or just voltage. It seems either cause fish and coral just as much stress. Not to mention if you have Voltage you need to have a ground probe just to make sure you dont become the Ground..Sure the voltage going through the tank to the Ground probe causes Current, But I don't see anyother way to fix the stray voltage. The magnetic feild from heaters power heads ECT cause stray voltage..So you don't need a leaking powerhead or bad heater.. The devices them selfs cause a small voltage in the water. Even lights seem to be able to cause some stray voltage in a tank.. Basicly you can't fix the cause in most cases and the only way to fix the problem is a ground probe..

As far as tripping a GFCI, My guess is it doesn't trip because the voltage is low and is probably only a few mA. If you increased the Voltage or the Amperage like say a faulty power head the GFCI would trip. They never said you can't get shocked with one. Just you shouldn't get a shock strong enough to kill you :eek2:

Will
 
so that i understand:

1) cant fix the cause
2) can mitigate the causes, check your appliances for leaks
3) use the grounding rod
4) put it close to the heater/pump/etc so that if there is stray current, it takes a small path away from fish

above all, it all has to be on a gfci.

yes?
 
Pretty much except you can't really cut down on the path.. If you give the voltage a Ground there will be current in the tank. Really no way around it. Since you have Current in the water the entire tank will have current not just point to point.

For sure above all have a GFCI. Or even better have two and split your pumps up one each. So if one trips for no reason your tank still has waterflow!

Will
 
lol well I ment to say "Split your pumps up on each".. But what I think and what I type are almost never the same :eek2:
 
HEY WILL...

when are we going to go to lunch? i owe you for drilling my tank. come look at my tank in my office, then we'll go to lunch one day this week. when is good?

tim
 
<a href=showthread.php?s=&postid=10584776#post10584776 target=_blank>Originally posted</a> by 8BALL_99
Pretty much except you can't really cut down on the path.. If you give the voltage a Ground there will be current in the tank. Really no way around it. Since you have Current in the water the entire tank will have current not just point to point.

For sure above all have a GFCI. Or even better have two and split your pumps up one each. So if one trips for no reason your tank still has waterflow!

Will
Click to expand...

I had a breaker trip the other day, dont know why it did. I do have two separate breakers running my setup as well. The breaker that trip runs the sump works and lights, and my other runs the power heads in the tank. Both circuits have GFCI on them. A GFCI works as separating the Natural Ground from the AC Negative which is also a ground. In a normal system the Negative is ground and when you have a three prong devise it is just double grounded. The GFCI separates the two all the way to the breaker or plug-in devise. So anytime the Actual Ground touches the Negative (ground) it will trip, but only in that circuit with the GFCI. IF you touch a ground to a Negative anywhere else in the breaker box nothing happens because they are the same thing. You can see for youself that the grounding strip is already connected to the Negative strip inthe breaker box. The GFCI monitors both the Hot AND the Neutral not just the Hot like a standard breaker.

The GFCI just separates the two so if any amps get sent to the Actual Ground (any ground including you) it will trip. You might say that it will only work with a grounding probe in the water. Well that would help but you dont need one for it to work because it is electronic and monitors the amps in the system and if there is anything out of the ordinary it will also trip. (remember the CGFI monitors both side of the circuit HOT and NEUTRAL) For example, a powerhead doesn't run very good out of the water, if you hook it up to a GFCI it should trip 9times out of ten because the powerhead is having trouble running and the circuit can sense this. (I've done this numerous times)

Now wether or not voltage or current causes stress on the fish, Im not sure which would do it but the current is what will shock you. Ground probe or not if you aren't using a GFCI and you have a problem you WILL BECOME THE GROUND! For a little extra safety always wear wear nice insulated shoes when working with the tank. Even when working with the little amount of voltage in a phone line will shock you if you aren't wearing shoes. (done this too :) ) If there is no ground probe in the tank and there is a problem (ie Short that has not already tripped the GFCI) you would not get shocked if you are wearing good shoes because you are really just touching a Hot wire and with out a ground you can do this. You can take off an outlet cover and can touch the black wire ONLY if you are not grounded!!! But not a smart idea, always touch the neutral and hot together first to make sure the breaker is tripped.

If there is a ground probe then you will get shocked even if you are wearing shoes because the circuit has already been closed.

For me, it would be better not to have a ground circuit in terms of my own safety. I come before my fish.


Here is a quote on how a GFCI works:

"A GFCI monitors the amount of current flowing from hot to neutral. If there is any imbalance, it trips the circuit. It is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second.

So let's say you are outside with your power drill and it is raining. You are standing on the ground, and since the drill is wet there is a path from the hot wire inside the drill through you to ground. If electricity flows from hot to ground through you, it could be fatal. The GFCI can sense the current flowing through you because not all of the current is flowing from hot to neutral as it expects -- some of it is flowing through you to ground. As soon as the GFCI senses that, it trips the circuit and cuts off the electricity."
 
Last edited:
Another example of a GFCI working with only a two prong plug is a hair drier. This is why the electrical code is having a GFCI in all bathrooms and kitchen. If there is any current that is not going straight from hot to neutral it will trip. Like a hair drier dropping in water, there is no ground in the sink of water but the current now runs through the water too and the GFCI sense the current change and trips. Just another example why a ground probe is not needed in the system.
 
But the thing is even with a GFCI you have stray voltage. So you still need a ground probe to take care of it. Also if you didnt' have a GFCI your still safer with a probe then without one.. Yes you probably will become ground with one ,but Eletricity looks for the path of less resistance. A metal probe conected to a good ground is almost always going to give less ressitance then a person.. You might get shocked in a bad short, But most of the current should run through the probe to ground insted of through you to ground..

Yes if you have a GFCI a ground probe is much less of an issue.. If you have a pump leaking much juice at all your GFCI will trip with or without a probe.. The idea for the probe is just to give the current a better ground then you.. Like you said the biggest bother with them is false tripping.. Mine seem to do pretty good with this.. I've got 6 ballasts connected to mine including god knows how many other things and mine have never tripped. This is with 3 circuits all on GFCI's..

will
 
This is just a thought, isn't saltwater going to give off a little voltage anyway even if nothing is in it? With all that Alkalinity and PH balance you would think it is like a lemon. I have never tested it, but I know a lemon has volts.
 
If I remember right the lemon trick only works if you put two differen't metals in the lemon.. Like a steel nail and a copper penny. But yeah saltwater is acidic so it would probably do the same trick. I don't think it would be very much at all though.
 
What Will said.
From dictionary*com: "...A typical battery, such as a car battery, is composed of an arrangement of galvanic cells. Each cell contains two metal electrodes, separate from each other, immersed within an electrolyte containing both positive and negative ions..."
So the Lemon doesn't have voltage. The acid is an electolyte which when two dissimilar metals are introduced seperate from each other,
"A chemical reaction between the electrodes and the electrolyte, similar to that found in electroplating, takes place, and the metals dissolve in the electrolyte, leaving electrons behind on the electrodes. However, the metals dissolve at different rates, so a greater number of electrons accumulate at one electrode (creating the negative electrode) than at the other electrode (which becomes the positive electrode). This gives rise to an electric potential between the electrodes,..."
The lemon becomes a battery.
So that is why Allen's bucket of Saltwater showed no voltage, no dissimilar metals.
I was gonna check my tank, but I can't find my meter.
As to the rest of the discussion, I'm still on the fence. I have a ground probe in one of my tanks, but I haven't gotten one for the other one yet. Placing the ground probe close to powerheads or heaters may help you notice a problem sooner in that there is a shorter path to ground which means less resistance-more current. So perhaps a lower voltage leak would trip a GFCI if it has a lower resistance path to ground. But how would you get a ground probe close to all of the equipment in your tank?LOL
I shut up now, starting to ramble.
disclaimer: I am not a licensed electrician. These are merely my opinions do not try this at home. :)
 
GFCI's trip only when current drops to a certain degree thus indicating a ground fault (current flowing to ground rather than along the regular path, hence ground fault interrupt). This makes them less effective with non grounded items.

Most likely you've got either a few current leaking items (I'd check the heater) as well as a nice coating of salt creep on some of your cords.

On the topic of distance from ground probe to whatever item you think is leaking, it may be futile. Salt water is much more conductive than freshwater and thus the resistance of a few centimeters verses a few inches probably wont make much of a difference.

And then we can get into ground potential rise wherein if whatever your outlet is grounded to has a rise in potential (something else grounding to it). This is typically the problem at fault when GFCI's trip for seemingly no reason at all. If your circuit shares a common ground (which it should) and another outlet somewhere else in the building experiences a current flow to ground the buildings common ground will experience a rise in potential (hence Ground Potential Rise). Given that your getting readings from your tank, this is most likely NOT the culprit.

I'd suspect an item such as the heater is leaking current along with a mixture of other items possibly leaking current or drawing current up via salt creep.

Those drip loops are a great idea eh?
 
You must log in or register to reply here.

Similar threads

T
Stray Voltage - GFCI Question
Replies
12
Views
670
Cruzersmith
C
C
Two Red Legged Hermit Crabs One Shell
Replies
3
Views
349
griss
griss
C
Thoughts anyone?
Replies
7
Views
365
Cool Fish
Cool Fish
Itchy Trigger
Heaters for Sump and for Storage Tanks
Replies
2
Views
340
aquaman67
aquaman67
Reefing102
My UPS - Do you have a UPS back up?
Replies
7
Views
543
Guygettnby
Guygettnby
Back
Top