Electrical Safety and Your Tank

[staindsoul]

I just wanted to offer up a quick guide to electricity and our tanks to help out people with little to no experience on the subject. I do NOT claim to know it all, there are far more intelligent people on this site with more accolades than me. I am a electrician working primarily in industrial controls and power for 10 years now. I have gotten a ton of info on this site, and have become addicted to this hobby. I can't offer a lot on reefs yet, but I wanted to help out on what I can.

Safety Measures You can take:

GFCI's

A gfci operates by measuring the current between the ungrounded ("hot") conductor and the grounded conductor (neutral). If it becomes unbalanced it will trip and turn off the circuit. Meaning, if the circuit is pulling 5 amps, and .005 amps strays to anything other than the return path of the neutral, ie the grounding conductor or you, it will trip.

A gfci is primarily to protect you. It will also protect the tank, but it is there to keep you alive. It is HIGHLY RECOMMENDED!! It can come in a power strip, recptacle or breaker. They all work the same, one may last longer than the other.

Surge Protector's

These typically come in power strips that are cheap and come in power strips. They inhibit a voltage spike to protect equipment that it is supplying power for. They do not offer any protection for you.

A surge protector may be a hazardous piece of equipment, that a gfci, afci, or circuit breaker may not (highly probable) stop from causing a fire or damage. Please, please do a ALOT OF RESEARCH before you decide to use this or not. There is a risk to using them that IMO doesn't outweigh the benefits of protecting my tank equipment. Thanks to Westom for schooling me on the danger of these here
-->http://reefcentral.com/forums/showthread.php?t=2217431&highlight=surge+protector

Some more threads that a surge protector didn't go well:
http://www.atlantareefclub.org/forums/showthread.php?t=55174
http://www.reefsanctuary.com/forums/equipment/78437-my-110-tall-had-fire-over-weekend.html
http://www.esdjournal.com/techpapr/Pharr/INVESTIGATING SURGE SUPPRESSOR FIRES.doc

Ground Probes

A ground probe should be used in your tank. It is used for stray voltages. (see bottom for stray voltages). A ground probe will put your tank at the same potential as your grounding conductor in your electrical system. IMO, you should use it with a gfci. The probe will put the tank at the same potential as your grounding conductor for tripping your circuit breaker. However during the time it takes to clear your breaker, your tank will be experiencing high current levels. If a gfci is used in conjunction with a ground probe, it will trip the circuit before the current reaches higher levels and may not even trip the circuit breaker.

Afci Breakers

Afci breakers are newer. The NEC is starting to require these breakers in many new locations in residential homes. A afci stands for arc fault circuit interrupter. A afci does not replace a gfci! A afci monitors the circuit for any arcing on ungrounded to grounded or ungrounded to grounding conductor faults. They use a circuit board to monitor the current sine wave, recognizing a short circuit fault and opening the circuit. They are not cheap, but can be used as a great safety feature. They compliment a gfci recptacle. I am not using one yet, but will be shortly. In theory you could have water splash and produce a arc fault from ungrounded to grounded and never trip a gfi.

A link:
http://www.pfeiffereng.com/The Arc Fault Circuit Interrupter.pdf

Stray Voltages:

Many people grab a meter and think they have a stray voltage in their tank. When in reality they don't. The BEST way to ensure you don't have any stray voltage is a gfci and ground probe in your tank. Stray voltage readings are meaningless without current readings.

To properly test your tank: take one probe on your meter while set on VAC to the grounding conductor and one probe to water surface of your tank. If you do not have a grounding probe you WILL read a voltage.

When I did my results were 24vac to the grounding conductor. When I did it to the grounded (nuetral) conductor I got 39 volts, and to the ungrounded conductor I got 69 volts. My current readings were 0 amps. These voltage readings are harmless. They are shown because of induction and difference of potential of two separate conductors. Stray voltage should be a concern when it gets closer to 105 vac or more, but a gfci and ground probe WILL alleviate any of those concerns of having stray voltage and not knowing it. If a gfci trips, you can troubleshoot from there.

After a ground probe is installed my tank the readings were the following:

Tank to ground conductor- 0 volts
Tank to neutral conductor- .112 volts (the difference would be the distance to the panel bonding conductor, it is of no concern)
Tank to hot conductor-123 volts

I will say it one more time, if you believe you are having stray voltage issues, and do not have a gfci at minimum on the tank power supply, GET A GFCI RECPTACLE OR POWER STRIP. It is not a cover all solution, but it does cover a majority.

Tips:

Heat is a great warning sign for any electrical problem. Check your cords, power strips,and power supplies by hand for any warm or warmer than normal spots, while checking for frays, knicks, cuts, etc. Do this monthly or more.

A gfci does not last forever, consider changing it yearly or every 2 years. Use the push to test once a month to make sure it is still functioning.

IMO, the perfect setup is a gfci recptacle, non surge suppressor dj power strip, and a tank ground probe. But check multiple sources before you make your decision.

 

[sleepydoc]

It was never clear to me what the purpose of a grounding probe was on top of a GFCI. In general, voltage isn't the issue, current is. As you indicated, you had 69 volts, but that voltage was unable to generate a current. If you have a GFCI and it generates more than 5 mA, it should trip, right?

As far as the fish in the tank go, as long as the voltage is static and uniform (which it should be in a conductive fluid,) they shouldn't know the difference. Voltage is a potential which has to be measured relative to something else. By convention, we arbitrarily define ground as '0,' but if you're sitting in the tank and have no clue what ground is, it shouldn't matter.

+1 the comments on GFCIs. Get an outlet or a GFCI extension cord before you find out why you need them!

 

[staindsoul]

Yep a gfci trips on a 5ma imbalance between hot and nuetral. The ground probe puts the tank at same point of reference, which is what the nec tries to do in all locations, that are not meant to carry current, to trip the source breaker. If you run a ground probe without a gfi and do have a fault, your gonna fry your inhabitants. If you don't run a ground probe or gfi and have a fault or true stray voltage your inhabitants should be ok, think squirrel on a high voltage line or bird on the same, but you are going to shock or electrocute yourself when you put your hand in the tank. If your body is grounded when you stick your hand in the tank, YOU will become the ground probe.

It was never clear to me what the purpose of a grounding probe was on top of a GFCI. In general, voltage isn't the issue, current is. As you indicated, you had 69 volts, but that voltage was unable to generate a current. If you have a GFCI and it generates more than 5 mA, it should trip, right?

As far as the fish in the tank go, as long as the voltage is static and uniform (which it should be in a conductive fluid,) they shouldn't know the difference. Voltage is a potential which has to be measured relative to something else. By convention, we arbitrarily define ground as '0,' but if you're sitting in the tank and have no clue what ground is, it shouldn't matter.

+1 the comments on GFCIs. Get an outlet or a GFCI extension cord before you find out why you need them!

 

[lwillis22]

So where can we get a grounding probe? I am not sure what these are.

 

[mcgyvr]

There is really nothing wrong with surge protectors or power strips when used properly.

Most of you like to "hide" your ugly outlets/cords in the stand under the tank with the sump which places them in a "damp location" which can lead to excessive corrosion or water intrusion.. This is more than likely the problem.. Not a surge protector itself.
Its always a good idea to #1 include drip loops in all cords when the piece of equipment is located higher than the outlet and #2 don't put power strips in a damp location at all.

 

[SaltyWenStirred]

I also put a clear, outdoor, plastic outlet cover over my outlet to protect it from salt creep or saltwater.

 

[staindsoul]

mcgyver, check into metal oxide varistors that heat up after excessive voltage spikes or long term use. there is a risk there. like you said, if used properly. which means you better be checking it for excess heat and replacing it often, but you cant pin a time frame, because how frequent are your voltage spikes. every system varies. thanks on the drip loop, forgot to mention that.

There is really nothing wrong with surge protectors or power strips when used properly.

Most of you like to "hide" your ugly outlets/cords in the stand under the tank with the sump which places them in a "damp location" which can lead to excessive corrosion or water intrusion.. This is more than likely the problem.. Not a surge protector itself.
Its always a good idea to #1 include drip loops in all cords when the piece of equipment is located higher than the outlet and #2 don't put power strips in a damp location at all.

willis, any of the online aquarium vendors carry them. marine depot etc.

So where can we get a grounding probe? I am not sure what these are.

nice.

I also put a clear, outdoor, plastic outlet cover over my outlet to protect it from salt creep or saltwater.

 

[jerpa]

I wouldn't use half the surge protectors they sell on a lamp let alone my tank. The problem with most, besides the construction of the outlets themselves, is that they are contained in plastic boxes that melt, smolder, and sometimes burn when those components fail. Here is a good article on the various power strips available and the design flaws in many.

Outlet Strips

Ground Probes

A ground probe should be used in your tank. It is used for stray voltages. (see bottom for stray voltages). A ground probe will put your tank at the same potential as your grounding conductor in your electrical system. IMO, you should use it with a gfci. The probe will put the tank at the same potential as your grounding conductor for tripping your circuit breaker. However during the time it takes to clear your breaker, your tank will be experiencing high current levels. If a gfci is used in conjunction with a ground probe, it will trip the circuit before the current reaches higher levels and may not even trip the circuit breaker.

I don't want to debate the necessity of the ground probe but I would argue that a GFCI MUST be used if a ground probe will be connected to the tank. I consider a GFCI mandatory anyway but using a ground probe without a GFCI introduces many potentially deadly scenarios that did not exist before.

 

[mcgyvr]

mcgyver, check into metal oxide varistors that heat up after excessive voltage spikes or long term use.

MOV's were a serious problem YEARS ago (like in the 70's) because the epoxy used to encase them was highly flammable. Standards have changed quite a bit since then and now all MOV's used in surge strips are required to have a flammability rating of UL94V-0 or greater.

 

[mcgyvr]

As to grounding probes..
First..yes you must use a GFCI outlet in combination with a ground probe..

The use of a ground probe is highly debated here.. Some (like myself) use one for my own personal protection and could care less if the increased potential to conduct current could be detrimental to the inhabitants of the tank.
Others don't use a ground probe simply because they feel this potential is damaging. But to date there is NO proof that a ground probe is bad for the tanks inhabitants and in fact there are cases that the introduction of a ground probe into a tank has cleared up head and lateral line disease in fish.

Pump motors,etc.. can create this "static stray voltage". If a ground probe is used that static voltage now has a path to ground and current "can" flow. But all I care about is that if the waterproof seal on my heater or pump or whatever decides to not do its job anymore that the ground probe will protect me when I place my hands into the tank.

 

[knight2255]

Thanks, just picked up a ground probe.....didn't really understand the need until this thread.

 

[staindsoul]

I agree with you and mcgyver, but I didnt want to command this and other items, because sure enough someone will come in and get all upset. Tried to stay nuetral, and just give my opinion. Not thou shalt.

I don't want to debate the necessity of the ground probe but I would argue that a GFCI MUST be used if a ground probe will be connected to the tank. I consider a GFCI mandatory anyway but using a ground probe without a GFCI introduces many potentially deadly scenarios that did not exist before.

Your welcome.

Thanks, just picked up a ground probe.....didn't really understand the need until this thread.

 

[sleepydoc]

Still not clear on the need for a ground probe; assuming you have a GFCI, if there's a voltage capable of driving a current, the GFCI will trip, regardless of the presence or absence of a ground probe. (if you have a ground probe in the tank and current flows, it should trip as well.) If it is a voltage that can't drive a current, then there should be no concern.

I don't know the data on head/lateral line disease and grounding probes, so if it prevents it, that may be reason enough, regardless of theoretical safety issues.

 

[staindsoul]

i believe that is the line where the debate starts about using a ground probe or not. the only scenario i dont like is, what if the gfi shunt trip has failure and wont trip. if i put my hand in there and i become the ground probe. not good. the ground probe would complete the circuit draw a high current and trip the breaker. it would harm the tank, but better them than me. this is thinking outside the ground probe putting the tank at the same potential as the grounding conductor and eliminating that potential voltage with no current. which in theory shouldnt be harmful to the inhabitants, but like mcgyvr said putting a probe in has cleared up some peoples issues.

i like it for my safety, as a backup to a gfi.

Still not clear on the need for a ground probe; assuming you have a GFCI, if there's a voltage capable of driving a current, the GFCI will trip, regardless of the presence or absence of a ground probe. (if you have a ground probe in the tank and current flows, it should trip as well.) If it is a voltage that can't drive a current, then there should be no concern.

I don't know the data on head/lateral line disease and grounding probes, so if it prevents it, that may be reason enough, regardless of theoretical safety issues.

 

[sleepydoc]

...but better them than me.

No disagreement on that point!

like mcgyvr said putting a probe in has cleared up some peoples issues.

It'd be interesting to see if there's any data on that. I'm imagining not, but I'll have to see. Another possibility - it could be that the probe contributes trace amounts of titanium to the tank, or acts as some sort of scavenger and that clears up the disease, rather than the actual grounding itself. Absolutely no proof or data on that, but just a theory. :idea:

 

[staindsoul]

It'd be interesting to see if there's any data on that. I'm imagining not, but I'll have to see. Another possibility - it could be that the probe contributes trace amounts of titanium to the tank, or acts as some sort of scavenger and that clears up the disease, rather than the actual grounding itself. Absolutely no proof or data on that, but just a theory. :idea:

like you said, i dont think there is any clear data. Mcgyvr mentioned it also. I would be inclined to think in those cases there was just enough of a current draw (in the low milliamps) that it affected the fish over time. my theory. Like the farmers that have stray voltage with cows being born with 5 legs and no butt. :spin2:

 

[mcgyvr]

yeah there is no scientific data as the causes of HLLE is really still up in the air.. carbon/stray voltage,etc..

I have just read a few posts where HLLE issues went away after the introduction of a ground probe with no stated/known other changes.

I haven't seen a single post where a ground probe is proven to cause an issue though.

 

[WillM]

I recently set up a tank and have had it running for about 2 months. I have tried putting some small soft coral as a sort of "canary in the coal mine". The zoas have fried looking skirts (looks like they get if you have an alk spike). All the parameters are normal otherwise (Nitrates are close to 0, alk 9, calcium 420, mag 1300).

The reason I'm posting here is that I can feel a small tingle when I place my hand in the tank, generally around cuts on my hands. This is not the way normal SW feels on my hands, I know what that is. This is definitely electrical. I don't have a voltmeter or any electrical know how beyond the basics. I unplugged everything and then started plugging it back in one at a time until I felt the tingle again. It is my lights, which aren't even immersed in the water (they are not the cheap crap aquatraders lights either, they are a little older, but made by coralife).

So, the question is, can the flourescent lights induce a current? My house is old so although the light fixture has a grounding prong, it isn't grounded. It's running on a timer that is not grounded. Grounding my house isn't really an option without rewiring everything and I just bought the house, so $3000 to rewire it isn't in the budget right now.

Then the follow up question, if I can feel this tingle, is that what is frying the zoas tips?

 

[staindsoul]

how is your light mounted and how is everything plugged in (all one power strip, into one receptacle or gfi?)?

w/o a meter to actually see if have current flowing in the tank, this will be hard. i cant answer if the possible current is affecting the zoa tips, i havent personally seen the affect on corals.

 

[Bike2k]

Can anyone recommend the b est way to install a ground probe?