Who really trusts GFCI

[REEFKEEPA]

Just asking.
Do you really trust that a GFCI would trip if salt creep got into a power strip and created a bridge that could act as a semiconductor creating a balanced load between line and neutral that is undetectable by the GFCI?
What happens when the bridge gets dirty and becomes more resistant? Does it then become thermal? If so can't it draw the entire current limit of the CB before the breaker trips?:rolleye1:

[MiddletonMark]

Mine has come in handy when electrical devices have fallen into the tank - which is what mine's main purpose is IMO.

I'm still here to tell two stories of lights going into the tank [while my arm's in there, too].

[Runner]

It depends on what you mean by "trust" and what the alternatives to "trust" in would be. If you mean to imply that we should toss the GFCI because a salt bridge might happen where it would not trip until catastrophic failure of the power strip, then NO.

[REEFKEEPA]

Good point. That's what they are designed to do. Protect you.
However a lot of people think they will protect your equipment.

[Runner]

Their purpose it to protect people. If you want to protect equipment you get a GFEP breaker which will only trip at 50 ma (10x the 5 ma instantaneous trip setting of the GFCI breaker).

[REEFKEEPA]

There is a guy who is a moderator on another forum
who's GFI tripped while he was on vacation and he lost his entire 10 year old 300 gallon tank. He could not find any evidence of why it happened. Thats what I mean by Trust.

[Runner]

It happens. Mine used to trip on a power outage restart when both my tanks and all their lighits came on together. I fixed that by dedicating circuits to each tank.

I'd rather use one and have it be there with a chance of working when I stick my hand in the tank with faulty equipment. I wouldn't put a ground probe in without one, either. Then again, I wouldn't put in a ground probe...

You haven't offered an alternative yet.

[Fred_J]

I got shocked by my 55g tank. I unplugged several things and everything's OK. I have a multi meter, but how do I test all the sealed devices. I do not have a ground probe in this tank , If I use the probe from my other tank can I check the sump out by placing one probe in the water and the other on the ground?

[REEFKEEPA]

Why wouln't you put in a ground probe?
To me it creates the least path of resistance.
Being an electrician and actually working with live circuits I know what can happen. 277v is not forgiving. We learn to make certain we do not become a path to ground.
I would never touch a peice of energized equipment in a tank.
I'ts almost like asking for it.

[REEFKEEPA]

My alternative is to power down before you risk your life.

[REEFKEEPA]

Runner,
The Arc fault breakers that are required in bedrooms in dwellings by the NEC have major issues.
You can weld with them. They don't work.

[Fred_J]

REEFKEEPA Everything is powered down, except a filter and light. But how do I narrow down which piece of equipment in my sump is bad. I know I need another ground probe for this tank. I just need to find out what is causing the leak. If it tripped the GFCI I could plug them 1 at a time.
Please advise.

[sttroyiii]

Lol. Welding...that brings back memories. Ive seen a lot more faulty breakers than GFCIs. I completely melted the ends off of some diagonal cutters in a 277v exit sign one time.

I would have to compare this to seatbelt use. I have met some people who say they will not wear a seatbelt no matter what because someone told them a story of someone being 'saved' by being ejected from the car. I think it will help in more cases than hurt, so it should be done. Now I dont think there should be a LAW to make you use a GFCI/seatbelt , but thats another story. I think people should be able to make their own decisions until it affects someone else. GFCIs should be required in apartments, but not in houses where your stupidity wont kill anyone else. Just some random $.02 thoughts....

[REEFKEEPA]

I would get a digital multimeter. Any one will do and check the water with one lead and ground with the other.
Power up one piece of equipment at a time and note any changes.
Sometimes you will get some "tracking" from salt creep from your lights.
Time to do a thourough clean-up if that is the case.

[REEFKEEPA]

sttroyiii
Agreed,
It depends on the person.
Most people don't realize that when they stick their arm in a fish tank and grab a powerhead cord wit the other hand that they could be electrocuted.

[OnTheReef]

Power up the devices one at a time and test with a voltmeter. Put the ground from the voltmeter in the ground of an outlet, put the hot from the voltmeter in the water near the powered device. I have had to hunt for leaking devices like this twice now: once it was a powerhead and once it was a powered hang-on filter.

[RichConley]

<a href=showthread.php?s=&postid=7060289#post7060289 target=_blank>Originally posted</a> by sttroyiii
LNow I dont think there should be a LAW to make you use a GFCI/seatbelt , but thats another story. I think people should be able to make their own decisions until it affects someone else.

Everytime someone not wearing a seatbelt is thrown from a car, it raises my insurance premiums. Also, in certain situations, not having a seatbelt can cause people to lose control of a car (IE you slide in the seat). SO yeah, you not wearing a seatbelt does affect me.

As to the guy whos GFCI that tripped while he was on vacation.. thats why you have people check on your tank.

Also, who knows, maybe soemthing did happen. Water evaporates. Think of it this way, woudl he rather have had his tank die, or his house burn down.

[Runner]

@Fred_J: If it won't trip the GFCI, that makes it hard to find. Things to try are:

Check for salt creep up to the lights.

Put a ground probe in the tank where you wish to test the equipment and turn it on to see if the GFCI trips. Sounds like this one isn't working for you, though.

Pull equipment out and check resistance from the hot leg to ground and neutral and see if it is what is expected for that piece of equipment (the manufacturer would know for sure).


@REEFKEEPA: Neither is 480 VAC phase-to-phase forgiving when lock-out and testing techniquies aren't used. Been there, done that, had the nervous twitch for a while to prove it...

...but, I wouldn't have a ground probe because if you get a fault that doesn't draw enough current to trip the breaker you will fry your animals. You could even get a low flow of current (less than 5ma to trip a GFCI) and fry all your SPS and other sensitive corals. It just happened to a guy in my local reef club. Yes, a ground probe makes you the owner safer. Yes, it should always be used with a GFCI (because otherwise you'd have to put a large amount of current through your tank for 10 seconds to 5 minutes or so to trip the breaker). But I won't use it because I would worry about my livestock. Same thing now with the AFCI since somebody pointed out to me that there are nuisance trips caused in association with MH lighting and motors.

I've been thinking of making a pushbutton that will put the ground probe into the wall and trip the GFCI if a fault exists. That way if you do get a high-impedence insulation break-down, the current won't cook your critters until it gets big enough to trip the GFCI.


EDIT: OnTheReef had an excellent method (see above)...

[Runner]

<a href=showthread.php?s=&postid=7060135#post7060135 target=_blank>Originally posted</a> by REEFKEEPA
Runner,
The Arc fault breakers that are required in bedrooms in dwellings by the NEC have major issues.
You can weld with them. They don't work. I am aware of the issues with them from a while back. Mike Holt was on a rant about how they did not work properly. Looks like recent incarnations have made them better than what they first were: glorified GFCI breakers. I think they were just made so that electrical contractors could get an extra 18% O&P from installing the durn things... ;)

[aubee91]

<a href=showthread.php?s=&postid=7059968#post7059968 target=_blank>Originally posted</a> by MiddletonMark
Mine has come in handy when electrical devices have fallen into the tank - which is what mine's main purpose is IMO.

I'm still here to tell two stories of lights going into the tank [while my arm's in there, too].

My toddler knocking a light into my fuge is the main reason I installed a GFCI. And locks on the doors of my stand. Scared the heck out of me...

[flyhigh123]

i dont trust my gfci, so i removed it...

[REEFKEEPA]

In the pushbutton case, I think that is an excellent idea.
Why not take it a step further and install a built in digital ammeter. Ditto on the 480.
Thats why I went into electronics.
The arc created by 24v is a lot less than phase to phase 480.
Can you say it sounds like a sizzle instead of a bomb?

[REEFKEEPA]

I think they were just made so that electrical contractors could get an extra 18% O&P from installing the durn things...
I think they were looking at the manufacturers.:lol:

[cweder]

As often as they have gone off in the house on other appliances, usually for no good reason, even after inspection by a electrician. I put GFCI on some minor outlets. The crucial ones to keep the tank going I did not, ie. major circulation pumps. You cannot argue with there purpose however.

[REEFKEEPA]

As to the guy who's GFCI that tripped while he was on vacation.. that's why you have people check on your tank.
Have you ever had a power outage in your area?
It only takes a few hours to loose everything.
Cweder, That is exactly my point.
I want to see how many people trust their prized reefs to an unpredictable device that could ruin their investment.
As stated before, They are great in the bath, kitchen, basement and outside, but on your main circulation? Not me. If you were hooked up to a life support system, would you want it to be plugged into a GFCI?

[sjm817]

Mine seems to work well

I knocked my fuge light into the sump *click* GFCI tripped and nothing was harmed. I had a leak in my Kalk reactor topoff which soaked the stirbar motor. Same deal. It worked well.

I run my Tunze 6000 on a non GFCI outlet. If the GFCI trips, I still have circulation in the tank.

[REEFKEEPA]

Good deal,
That's what they are for. I think all lighting should be GFCI protected.
It is not a critical element of survival for the tank inhabitants.
If your light fixture had fallen into your sump while energized and your GFCI failed to trip you could have been hurt or worse.
They have their place.
IMHO just shut down for a few minutes when sticking your arms in the tank.

[REEFKEEPA]

bump

[xtrstangx]

Our whole house is either GFCI or AFI. Arc fault interrupters work like a GFCI, but trip when it arcs. I keep my tank all on GFCI. IMO, a powerstrip starting on fire isn't as important as my life.

[REEFKEEPA]

Ever test your Arc fault ? I hope they arent GE.

[REEFKEEPA]

bump

[Fred_J]

Thanks everyone, it turned out to be my return pump.

I started using the ground probe because some type of electrician or engineer said there was residual/background electricity in most tanks. This residual currant would cause false PH and ORP measurements and would also irritate the inhabitants. It is just one of those flimsy things you get at the LFS. In fact I was planning (whenever I sent in another online order to get one for the tank as well as the pump.

Are you saying the only purpose is to save the aquarist from shock(not that that's not an important issue).

I'm planning on leaveing next week to see my parents for two weeks, glad it happened now.

[Runner]

The only purpose of a ground probe is to save you from shock -- hopefully by tripping your GFCI long before you put your hands in your tank. The presense of a ground probe increases the chance of cooking your tank because it allows current to flow and irritates livestock. Only use it if you have a GFCI to take care of the current at low levels. Even then, be aware the current flow can be great enough to cook sensitive corals with reaching the 5ma threshhold to trip your GFCI.

And don't believe every electrical engineer or electrician you speak with -- we speak passionately whether or not we know for sure what we are talking about. :)

[wojo]

REEFKEEPA, i have everything running on GFCI and my worst fear is that one day i will come home from work and it will all be dead cuz it tripped for no reason.

Would you recommend leaving return pump and heater outside of GFCI and plug everything else into it? My heater is in my sump.

Thanks...

[Ddddrgnfly]

"Quietly lurking in the shadows"

[REEFKEEPA]

I can't recommend that you don't use GFCI on everything because I don't know you or your situation.
But I will never have my return pump plugged into one.
PS It is an EXTERNAL pump.

[wojo]

having just the pump running would not help me cuz the temp would drop too much without the heater. so i think i would need both, btw my heater is titanium made and my pump is mag9.5, they dont seem to have too many shocking stories behind them do they?

[Runner]

Ideally, you should have two seperate GFCI circuits and have at least one pump on each one. Of course, I don't do this myself but it is still a good idea. ;)

I have two GFCI receptacles for my tank -- one feeds the lights and fans and the other feeds everything else. I would divide the loads if I could, but the light receptacle is outside in my garage with my ballast box.

[wantahealthytank]

I had a few different breakers added, and had GFCI outlets put in where they would fit, and use GFCI power strips where they wouldn't.

I do have my pumps on GFCI, but they are on 2 different breakers. I was knocked to the ground by the tank before, and it scared the crap out of me. It took us a couple of hours (if that) to get everything done, and it didn't cost much either. I also have my canister filter and some power heads on seperate circuits. So even if both pumps fail their is still circulation in the tank.

The only time I've had one trip, was when I would have been shocked otherwise (something got wet and I didn't realize it until I went to touch it).

I would rather lose my tank, then my life or house.

Added to say:

THat I do not have all of my outlets in the same place, Some are in teh basement, some are under the floorboards, and some are hanging on the wall behind th tank, that way if there was some major leak some things would still be dry.

[Witchdoctor_h]

On the subject of ground probes, read this: http://avdil.gtri.gatech.edu/RCM/RCM/Aquarium/GroundingProbes.html

Good read.

[Runner]

Good analysis of the ground probe and the GFCI protection.

[xtrstangx]

<a href=showthread.php?s=&postid=7062778#post7062778 target=_blank>Originally posted</a> by REEFKEEPA
Ever test your Arc fault ? I hope they arent GE.

Not GE. SquareD just like the rest of our house. :D

[superfirefly]

<a href=showthread.php?s=&postid=7060333#post7060333 target=_blank>Originally posted</a> by REEFKEEPA
sttroyiii
Agreed,
It depends on the person.
Most people don't realize that when they stick their arm in a fish tank and grab a powerhead cord wit the other hand that they could be electrocuted.

I fall into the most people catagory, can you explain this further? Just the why and how. I had no idea that this could happen. You guys are making me scared to touch my tank now.

[REEFKEEPA]

Apparently this is one of those "personal preference" issues.
I would advise everyone who is not trained in electrical or electronics construction to protect themselves with GFCI receptacles or C/B. Personally, I know what it takes to be shocked/electrocuted and therefore treat my tank is if it were always "hot".:eek1:

[REEFKEEPA]

Superfirefly,
Use GFCI

[REEFKEEPA]

xtrstangx.
Good thing!

[superfirefly]

I have GFCI, I am just interested in the science behind this. I did not know that if I had one hand in the tank and took the dry hand and grabed an insulated power cord I ran the risk of electrocution.

[Runner]

Basically (very basic), a GFCI works as follows. When you look at a normal 120-volt outlet in the United States, there are two vertical slots and then a round hole centered below them. Assuming the round ground hole is down, the left slot is slightly larger than the right. The left slot is called "neutral," the right slot is called "hot" and the round hole below them is called "ground." If the load plugged into the GFCI (lights, heater, motor, etc.) is working properly, all electricity that item uses will flow from hot to neutral. 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 5 milliamps (mA) and it can react and trip as quickly as one-thirtieth of a second.

Somewhat less basic: The monitoring circuit basically works by running both the hot leg and the neutral leg through a current transformer (CT) with current flow going in opposite directions. If the same current is flowing in both hot and neutral, then the currrent transformer reads 0 mA and the world is good. If current "esacapes" through an insulation break-down or fault from the hot or neutral downstream of the GFCI, then the difference in current transfers through the CT and is magnified over to the trip circuit. When this current gets high enough, the circuit will trip the contact and de-energize the circuit.

The test switch works by introducing a resistor between hot and neutral with only the hot leg passing through the CT. The resistor is sized for 5ma current flow to verify that the GFCI works.

Here is a sketch to show how this all works:
http://home.earthlink.net/~aquariapics/reef_board/gfci_circuit_faulting.gif

Notice that 50 mA up to 0.2 Amps at 120 Volts and 60 Hz is about perfect for sending a human heart into ventricular fibrilation. Anything greater than that will burn tissue and organs over a prolonged exposure time.

That should about do it. Please feel free to ask questions or tear this apart if I made an error.

[REEFKEEPA]

You are always taking a risk when touching any power cord that is connected to a receptacle of any type.
There could be a crack in the insulation that you don't see.
If by chance you touch anything that is energized, If you touch "GROUND" or anything else that is grounded, the current will take the easiest path to ground. When you are talking saltwater, you might as well be made out of copper.
Your skin resistance will be reduced to near 0 and you WILL become a conductor. If by chance a mere 3/4 of 1A passes through your heart you will be electrocuted. Voltage does not matter in this case. 1 amp of flow through the heart will stop it.
The main point here is when in doubt SHUT IT DOWN!!

[REEFKEEPA]

Runner,
I love that diagram.
The basic is basic to trained personell but the average reefer is going to get blown away by the coils and such.
If you have access to some manufacturers examples and can post
that would help.
PS I can't find any.
I really appreciate your POV on this subject and respect your knowledge as an EE.
How about a schematic on the arc fault.

[superfirefly]

Thanks for the reply reefkeepa. After I posted my post I reallized that is probably what you meant but when I first read it I was imagining myself leaning up against a powerhead cable and getting zapped straight through the sheilding.

[REEFKEEPA]

superfly,
I don't want you to be worried about it but it can happen.
just remember to keep one hand out and a dry pair of tennis shoes.
never reach into a tank that is running with bare feet!
GFCI or not. Don't touch anything that can conduct with your body.
The safest way to work on a tank is to power it down.
use supplemental lighting if required.

[Scuba_Dave]

I have 5 circuits providing power to my system
If even 2 of the circuits kicked out (pumps & Tunze), my battery back-ups would kick in
We have someone check our tank & cat every day while we are away. If you don't you are asking for trouble

My outlets for the most part are not near the tank. That's what a 6' power cord is for.
The GFI's are ALL installed farther away - no reason they need to be near the tank
I also replaced/protected every outlet in my basement & 3 season porch with GFI

Square D had a recall on their Arc Fault breakers - check it out

I've wired hot before in my younger days, too lazy to go down to the basement from a triple decker. Only stung a few times. Now I'm old enough to know I want to live longer

I've heard about pumps not coming back on after a power failure due to the GFI kicking out. I've never had it happen, doesn't mean it can't

[REEFKEEPA]

I warned about those arc faults.
I have gotten reports from some of my electrician "employees",
that they are a joke.
These guys are trained and seasoned 20+ years in the trade.
I trust their observation/opinions.
They hate them and would never put them in their houses.
Nor would I
Scuba_Dave,
I am glad that you have had success with your power ap.
Remember though about the vacation thing.
3 hrs max. It could happen while your at work.
I am suggesting that skilled/experienced reefers run their EXTERNAL circulation pumps on a regular outlet. and to disconnect it during maintenance of their tanks.
I know this is controversial but it is a matter of how much trust you have in yourself or someone else that might stick their arms into your tank/sump.

[Runner]

I do not know how an AFCI breaker works (I know -- that's an oxymoron). I believe the real ones (the high $$$ ones that protect switchgear) work by some kind of waveform analysis.