A Gentle Reminder about Electricity and Marine Aquariums

[billdogg]

Consider this a PSA for ALL who keep glass boxes of water!

Saturday while doing water changes and general cleaning, I broke the impeller on the PH in my Frag tank, so I just swapped it out for another old "spare" and went about my business. No worries!

Last night, I went to the basement after my shower, barefoot, to get a water sample for testing. Imagine my surprise when I dipped the container into the water and got bounced back a few feet!!!

I suspected the replacement power head was the culprit, so I unplugged it and went about my water testing.

Today after work, I broke out my trusty multimeter and plugged the suspect back in. (Y'all DO have a multimeter don't you??? - $15 at HD/Lowes)

For those who are not aware, you set the MM to AC 200V, put the black probe into the ground hole in any outlet and put the tip of the red probe in the water. It is perfectly normal to have a reading of a few volts due to the electromagnetic currents produced by out equipment. That is nothing to worry about. When I did it, the reading was 105V with the PH plugged in, 3.2 with it unplugged.

Anybody wanna buy a slightly used PH????? CHEAP!!!

j/k - it's in the trash.

In retrospect, I made 2 mistakes that I knew better than to do, but carelessness/complacency bit me in, well this time, the right arm.

They were:
1. Not inspecting old equipment for issues. Had I looked beforehand, I'd have seen the cracking insulation on the cord at the base of the PH.

2. Standing on a cement floor barefoot and sticking my hand in the tank - thereby creating a path to ground for the leaking current. WEAR SHOES, preferably with rubber (insulating) soles


A grounding probe would have done nothing to prevent this, and at least IMO, create a false sense of security and should not be used. There are certainly those who won't run a tank without also, and I fully support their right to do so!

The circuit IS protected by a functioning GFCI - I tested it as well - I'm guessing that I jerked my hand back before it was able to trip.

HTH!!!

 

[Sugar Magnolia]

Sorry you had to find that out the hard way, but it is a teaching moment for sure! Thanks for sharing Bill.

 

[billdogg]

This wasn't the first time!

About 1990 or so, aPH stopped working, so I pulled it from the tank and took it to the kitchen to clean. When done, I put it in a bowl full of water and plugged it in to see if it would work. It still wouldn't start, so I reached in to give it a shake. Next thing I knew, I was about 10' away sitting on the floor with no clue how I got there. I spent the next hour or so wandering around the house telling my gf (and myself)- "yeah, I'm ok" By all rights, that one should have been the end of my aquarium keeping - and everything else for that matter. Shoulda gone to the ER, but since I worked there I just couldn't face my coworkers after having done such a stupid thing.

I guess putting the PH in a METAL bowl in a Metal sink in a house with ancient, ungrounded receptacles wasn't the best choice.

I KNOW BETTER! I just got careless this time. And lucky again.

 

[lapin]

Power head got me once. Salt mixing barrel. Ouch. Not as good as the time when I was a kid and had a lamp cord plug break off on the end of extension cord. Tried to pull that out with my teeth. Ouch.

 

[SAT]

I've had a few shocks of my own... For my first job I apprenticed at an aquarium shop which had three rows of stainless steel tanks, all touching, with a long (GFCI? What's a GFCI? This was 1973!) power strip above each row, often wet. As often as not, we would get a nasty buzz when touching a tank.

I doubt a grounding probe would have completely prevented a shock, but it should have reduced the severity and drawn enough current so that the GFCI would have tripped.

 

[Sugar Magnolia]

This wasn't the first time!

About 1990 or so, aPH stopped working, so I pulled it from the tank and took it to the kitchen to clean. When done, I put it in a bowl full of water and plugged it in to see if it would work. It still wouldn't start, so I reached in to give it a shake. Next thing I knew, I was about 10' away sitting on the floor with no clue how I got there. I spent the next hour or so wandering around the house telling my gf (and myself)- "yeah, I'm ok" By all rights, that one should have been the end of my aquarium keeping - and everything else for that matter. Shoulda gone to the ER, but since I worked there I just couldn't face my coworkers after having done such a stupid thing.

I guess putting the PH in a METAL bowl in a Metal sink in a house with ancient, ungrounded receptacles wasn't the best choice.

I KNOW BETTER! I just got careless this time. And lucky again.

Oh lordy! You sir, are a lucky man to have survived that launch.

 

[heathlindner25]

Oh lordy! You sir, are a lucky man to have survived that launch.

It only hurts the first 17 times.

 

[mcgyvr]

I doubt a grounding probe would have completely prevented a shock, but it should have reduced the severity and drawn enough current so that the GFCI would have tripped.

First.. glad you are ok there billdogg..

Now.. The ground probe would have caused the GFCI to trip the instant that a suitable fault was happening in the tank and not waited until he stuck his hand in..
So if there was a ground probe this minor shock wouldn't have even happened at all..
Thats the only reason I give for the acceptance of ground probes.
They cause the GFCI to trip the instant a fault develops vs waiting for you to trip it or feel that shock..

 

[Dmorty217]

First.. glad you are ok there billdogg..

Now.. The ground probe would have caused the GFCI to trip the instant that a suitable fault was happening in the tank and not waited until he stuck his hand in..
So if there was a ground probe this minor shock wouldn't have even happened at all..
Thats the only reason I give for the acceptance of ground probes.
They cause the GFCI to trip the instant a fault develops vs waiting for you to trip it or feel that shock..

I'm willing to bet most aquariums aren't plugged into a GFCI, but I agree with you.

 

[HBtank]

Had a similar scare with a mixing drum, but only had a slight sensation near the cord. Had me investigate and saw ~70 volts in the container. But after digging more, I realized it was almost all induced voltage and the amps were at .003, barely noticeable.

Still threw the equipment away, but just mentioning that only looking at voltage on a meter can be misleading.

It's hard to find these problems without actually getting shocked (the "stray voltage" rabbit hole is real). GFCIs everyone! And yeah, I heard it is well beyond the pain threshold to trigger a GFCI.

 

[LeJeune981]

My last waterchange... I was scrubbing the rocks in my fuge.. I've got 2 30 inch t5s on top of a 46 gallon fuge..

What ever reason.. I didn't unplug the lights this time.. just stacked them on top of eachother and moved to the back side of the tank..

I'm scrubbing away.. not thinking of anything.. a lost my grip on a big Rock and dropped it... went to catch it with both hands.. elbow or something bumped the lights.. and both flopped over.. dropping right in the tank..

Kicked me out of the tank... rock still in hand before it popped the main breaker...

Stupid is as stupid does..

But as a pipe welder by trade.. and 20 years experiance... I am not new to the feeling of amps corsing threw my body on a way too regular basis...

A little story...
took 500 amps once...well twice.
Carbon arching in the rain.. in a stone quary.. on a tiny island in Lake Erie at 3 am.. nearest hospital is a 30 minute helicopter ride by coast guard.. I was 18 then

First shock. Blew me off the catwalk and gave me a heart attack...(I think..the ticker wasn't ticking right at all) second shock was my boss reviving me..


Thanks for the multimeter tip... I'm gonna check that tomorrow.. just to see lol

Sent from my SM-S907VL using Tapatalk

 

[mcgyvr]

I'm willing to bet most aquariums aren't plugged into a GFCI, but I agree with you.

well.. I hope you are wrong..
All line powered submerged equipment should be protected by GFCI..(RCD in other countries)

One big benefit of all of these DC powered pumps,etc... is the added safety of that low voltage DC.. No real shock hazards with those unless you drop the power brick into the tank

 

[cincyjim]

So from what I have read, watched on videos, etc, there is an acceptable range of stray voltage (a norm) you will have in the tank but no one is really saying what that is. In one video a guy stated stray voltage up to 50 is the ceiling at which point you need to start investigating where it's coming from. My question is, is there such a thing as a normal/acceptable range and a ceiling range? Thanks!

 

[SAT]

If the tank is ungrounded, voltage by itself doesn't tell you very much. To understand if there is a problem, you need to establish that the voltage can be sustained in the presence of some electrical current. If the tank is grounded and you still can measure significant voltage then you have a problem.

 

[SAT]

well.. I hope you are wrong..
All line powered submerged equipment should be protected by GFCI..(RCD in other countries)

One big benefit of all of these DC powered pumps,etc... is the added safety of that low voltage DC.. No real shock hazards with those unless you drop the power brick into the tank

+1. Saltwater, AC electrical devices, and no GFCI is a very dangerous combination. Children under 90 should not attempt.

 

[cincyjim]

Okay, so if I use a multimeter to establish a base stray voltage on a grounded tank (with a grounding probe installed) and then if I start to see the voltage creep up then I know I have a problem... right?

 

[Rover88]

Okay, so if I use a multimeter to establish a base stray voltage on a grounded tank (with a grounding probe installed) and then if I start to see the voltage creep up then I know I have a problem... right?

If you have a grounding rod installed, your voltage should not be creeping up. Your 'base' point at any point in the tank should be the same as ground, if your grounding rod is grounded.

 

[SAT]

Okay, so if I use a multimeter to establish a base stray voltage on a grounded tank (with a grounding probe installed) and then if I start to see the voltage creep up then I know I have a problem... right?

Yes, but in practice the voltmeter isn't much use unless you always check it before touching the water.

 

[mcgyvr]

Okay, so if I use a multimeter to establish a base stray voltage on a grounded tank (with a grounding probe installed) and then if I start to see the voltage creep up then I know I have a problem... right?

There is no need to put a multimeter in your tank to measure ever..
Simply ensure all line powered submerged equipment is protected by a GFCI that is routinely tested for proper operation and never look back.. Don't do that and well you are risking shock and possible electrocution and may win the Darwin award and probably shouldn't reproduce either .. (That comment is not directed at anyone in particular so relax mods... no need for an infraction..)

You can pick up a GFCI device for under $20 and they are available as power strips or outlets or even the breaker for the whole circuit..

If you don't know what to buy please contact me and I will happily send you a link to them.... In fact here..https://www.homedepot.com/p/Tower-M...gclsrc=aw.ds&dclid=CLKjjtj9hNgCFXjI4wcdbmgLaw
There are many more..

The advice to use a meter has caused more confusion than anything else IMO..
The impedance of todays meters is all over the place and they act as fantastic antenna that will register voltage just walking around your house holding them up in the air..

 

[cincyjim]

My outlets are GFCI protected and the OP stated theirs was as well but it didn't trip. I guess what I was looking to do was conduct a random check on the tank for stray voltage (a sign of something going bad) based upon a normal/base/known operating stray voltage.