Aquariums and GFCI

[Binare]

I'm amazed at how tanks I've seen over the years and even in discussions in pm where people don't have a GFCI on there tanks. Some people don't think they need it becuase their tank x amount of feet from the receptacle. Others just simply don't know what it is or what it does. A Ground Fault Circuit Interrupter (like your bathroom receptacle) is not just for saving you if you get water in the receptacle, in fact that may or may not trip. Ill use an aquarium heater for example, it has two wires... A Hot and an ID, when your heater turns on it draws all its current from the Hot. That current HAS to go somewhere, it returns on the ID. Whatever current enters that has to leave, the ID carries just as much current as the hot, a lot of people don't know this. What a GFCI does is detect a difference between the Hot and the ID. Let's say your heater craps out, the glass breaks, cord frays from heat. A crab digs the epoxy out of the hole sealing it, you now could have the water in your tank part of the live circuit. A GFCI would trip in this case, it would sense a difference in current between what's being sent out to the tank... And what's returning. Without a GFCI, you could go stick your hand in there and boom... You now could be the path for that current to travel to ground instead of the ID. Electricity aint picky, it will use children and pets just as easily. Now that you know, is it worth the 25 bucks and couple minutes to install one?

[Leah]

Well put. I aggree 100% on GFIC and think it is a must have. I worked for a women who
ran a Aquarium service. She had set up a huge tank S.W. for a customer had it running
and fully stalked when I saw it no GFIC after spending thoasands of dollars on other
equipment. She had been in the business for years, I could hardly believe it. Oh and top
it off the plug was right below the tank. She didn't have a clue.

[fkshiu]

A GFCI has saved my ass from being eletrocuted before. It's worth its weight in gold as far as I'm concerned.

[lastlight]

I just bought a pack of 3 at Home Depot for $40. No-brainer.

[Delphinus]

+1. It's too bad GFCI breakers are so expensive. But the logical workaround is to use the bathroom plugins because any downstream plug is also GFCI'd then in a way.

One thing has always confused me though. I hear 50% "this" and 50% "that", where one camp says a GFCI senses an imbalance between the hot and neutral wires, and the other camp says a GFCI senses any kind of current on the ground wire. Is it a case of "both are true" or is it a case of "the other one is an arc fault" (and if not, what is an "arc fault")? The reason I'm not convinced is because I once touched an otherwise all-powered-down light reflector (which was grounded), there was a static zap, and the GFCI tripped. (Nothing else was on at the time). So the static spark must have travelled to ground? That suggests GFCIs or at least THAT particular GFCI I was using at the time would trip on "current on ground" ?

One thing about GFCI's is I get these random trips, at the rate of say once per year or so. I'm not really sure what's up with that. That's an exceedingly difficult thing to troubleshoot and diagnose because I'll go through the checklist (unplug everything, add it back one by one, using a multimeter to see if there's any current to ground) and seemingly nothing will be the chronic misbehaver. I don't know if this means the GFCI is just dodgy, or it's some kind of very infrequent fault that comes and goes, or if my checkout procedure itself is "faulty" (pun quasi-intended )

[Binare]

Originally Posted by Delphinus

+1. It's too bad GFCI breakers are so expensive. But the logical workaround is to use the bathroom plugins because any downstream plug is also GFCI'd then in a way.

One thing has always confused me though. I hear 50% "this" and 50% "that", where one camp says a GFCI senses an imbalance between the hot and neutral wires, and the other camp says a GFCI senses any kind of current on the ground wire. Is it a case of "both are true" or is it a case of "the other one is an arc fault" (and if not, what is an "arc fault")? The reason I'm not convinced is because I once touched an otherwise all-powered-down light reflector (which was grounded), there was a static zap, and the GFCI tripped. (Nothing else was on at the time). So the static spark must have travelled to ground? That suggests GFCIs or at least THAT particular GFCI I was using at the time would trip on "current on ground" ?

One thing about GFCI's is I get these random trips, at the rate of say once per year or so. I'm not really sure what's up with that. That's an exceedingly difficult thing to troubleshoot and diagnose because I'll go through the checklist (unplug everything, add it back one by one, using a multimeter to see if there's any current to ground) and seemingly nothing will be the chronic misbehaver. I don't know if this means the GFCI is just dodgy, or it's some kind of very infrequent fault that comes and goes, or if my checkout procedure itself is "faulty" (pun quasi-intended )

The camp that says "too ground" is correct as well to a certain extent, any current going to ground... Is NOT going to ID. A common work around for old houses where receptacles don't have grounds is to put all those circuits on GFCI. In fact, its required by code when doing a reno or any other changes to the wiring in those cases.

You certainly can get nuisance tripping on GFCIs. Ceiling fans for example, on startup it will draw more current then when running. For a brief moment that inrush current will oppose a change in current between hot and ID if its a large enough difference and for a long enough period, GFCI trips.

Arc fault is entirely different, its name is self explanatory, senses an arc, code says they have to be used in bedrooms... You push your bed or mattress up against the wall, bend the plug down causing an arc... That breaker will trip, without it, you potentially have a fire.

The logical choice is to NOT use the a plug on the LOAD side of the bathroom receptacles, what happens when you plug your 1200watt hair dryer in? You will overload that circuit with pretty much anything else running on that same circuit... And trip the breaker... Making nuisance tripping even worse.

[Delphinus]

I'm not sure I follow you on that last paragraph, sorry. Is that about arc faults still? Or the nuisance tripping? But nothing else in my house is plugged into the circuits I run my tanks off - they are solely for the tanks and associated paraphernalia..

So how come my GFCI tripped on the static discharge when nothing was on? (I touched the reflector which was grounded, there was a zot, and the GFCI tripped.) There wouldn't have been an imbalance between hot and neutral in that case?? Sorry I'm just trying to understand why it happened.

Oh, one more question .. what does "ID" stand for? I know you're referring to the neutral wire in this case but I've never heard it referred to as ID before, just curious what it stands for?

[wolf_bluejay]

Just to +1 the GFI thing. A while ago when I was building my 220, I had moved my existing 90 out of the way and off the GFI while The new tank was getting setup. While messing in the sump I had the heater glass explode IN MY HAND while live. And I mean the whole glass shield came off.
Now, that did give me quite the shock, electrically and mentally as the using was sparking and zapping as I held on to it.
Since then, I always have a GFI. Thankfully the wife was standing there and the power bar it was plugged into was withing her reach
Save so grief and drip loop power cords, install a GFI and don't be silly. 120V might not kill you but it will at least hurt -- a lot.

[Binare]

Originally Posted by Delphinus

I'm not sure I follow you on that last paragraph, sorry. Is that about arc faults still? Or the nuisance tripping? But nothing else in my house is plugged into the circuits I run my tanks off - they are solely for the tanks and associated paraphernalia..

So how come my GFCI tripped on the static discharge when nothing was on? (I touched the reflector which was grounded, there was a zot, and the GFCI tripped.) There wouldn't have been an imbalance between hot and neutral in that case?? Sorry I'm just trying to understand why it happened.

Oh, one more question .. what does "ID" stand for? I know you're referring to the neutral wire in this case but I've never heard it referred to as ID before, just curious what it stands for?

I was speaking of nuisance tripping in the last paragraph... I'm on a cellphone, hard to keep track of what saying on a tiny screen

The rest well... There's a reason electrician have to go to school a quick run down though:

Referring to that wire as the neutral is INCORRECT even though everybody and their dog does, in a 2 wire system it is the identified conductor, it carries full current. In a 3 wire system its called the identified neutral, it carries the difference of current. Between the two hot conductors. Ie. Your stove is a 3 wire system... Technically called 3 wire edison. Now this is gonna get your goat, what you call the ground is actually just a bond, bonds all metal and equipment, boxes etc together. The id and the neutral are considered the grounded conductors. Inside your panel the neutral (is the neutral in the panel) is jumpered to the metal case... This jumper is the Common Grounding Conductor (if I remember correctly) then goes to earth... Or "ground".

A ground fault interrupt does exactly as its name implies... A fault involving the grounded conductor (identified conductor).

Static can cause tripping, so can inductive loads (motors) static is very high voltage... Even as high as 25,000 volts and very very little current, if that small amount of current introduced is high enough to trip it, it will. Remember kids, volts don't kill, current does. A gfci might trip out at 5mA, it might only take 10mA to kill you. A GFCI does not protect you from shock, it shuts the circuit fast enough that hopefully it doesn't injure you seriously, where as the circuit breaker in your panel doesn't care, its looking for the amps its rated for, you could electricy running through you all day long, as long as the total draw aint reaching what that breakers rated for. Simply won't happen with a GFCI, or atleast shouldnt

[Gizmo]

I'll just quip in with this: while yes the gfi can protect you, it can also be a danger to your inhabitants. By that I mean, say you went on a holiday. And you had all your gear plugged into this trustful device, and pop it has a nuceince trip. Pumps are down heaters are down and your tank is toast. I say run your lighting and non mission critical systems on a gfi but keep at a min one powerhead and a heater off that gfi