[rlong]

Hi,
A couple of day ago I went down into my bacement to do a water change on a Discus tank. I have a 30 gallon barrell where I prepare water. a couple of hours earlier I turned on my mixing pump and heater that I had laying ing the bottom of the barrell to bring the temp up to about 80^. So I was down there in my stocking feet and put my have in the water and received quite a suprise.

From the remains of the heater it looks like the ceramic core exploded. It was in about 20 pieces. Of corse the glass was broken also.

I figure it must have over heated big time.

 

[Green Leaf Aquariums]

Crap. sound lucky to be alive.

 

[AnneRiceBowl]

ohhhh....note to self on this one. I also make my water in a seperate container with a powerhead and a heater.

 

[rlong]

So,
I went out and bought a new creep heater (I'm money chalenged). Then went to Home Depot and bought a piece of 3" pvc, 2 end caps and a 1/2" hose fitting. Drill a 7/8" hole in one end cap, 3 1/2" holes close to the same end as the previous end cap. Then a hole for the hose fitting close to the other end cap.

So now when the heater is on for longer times heating up water from 65^ to 82^ there is a strong flow of water flowing past to keep the heat exchange working.

Oh - THe whole thing heater included was about $28.

 

[ruki]

I read similar stories from time to time on all the forums. Decided the stories made a good case to replace my aquarium outlets with GFCIs. I also put up a junction box with multiple GFCIs so if one component goes bad it won't shut down everything. This isn't absolutely necessary unless you have kids that might play with your tanks with bare feet...

It's a good idea to wear rubber soled shoes when doing maintenance on your aquariums. Wet bare feet can provide a low impedence connection to ground, and the neutral wire is connected to ground in your circuit box, so there it the potential for wet bare feet providing quite a good return path to complete an open electrical circuit.

 

[crazy loaches]

Glad you werent actually electrocuted (that would mean you'd have died!) but instead just recieved an electrical shock. Were you by chance on a concrete floor? Concrete can actually conduct electricity well enough. Did you maybe drop the heater in (maybe it shattered when it hit the bottom) or perhaps the heater was still running after the water level dropped below it and it overheated?

 

[rlong]

Hi,
yes, to say that I was electrocuted was a bit of an stretch and yes I was standing on concrete.

No, I didn't drop the heater, it had been laying in the bottom for quite a while. I'm not sure the a GFCI would have been triggered, the power cord was not hot, so I don't think that it was drawing more than normal.

 

[tropicalfish]

A short would have triggered the GFCI... Happened when I accidentally dropped an extension cable into the pond :O

EDIT: Correction to myself, shorts from hot to ground would have tripped the GFCI. See my post further down.

 

[crazy loaches]

GFCI should have triggered, as it triggers off the difference in current between the neutral and hot line (if there is a difference that means electricity is finding another way to get to ground other than through your outlet). It has nothing to do with the cord getting hot (you may be thinking of a regular circuit breaker which would trip with too high of a current flow which might heat up wires if it rises slowly that the breaker doesn’t immediately trip).

A GFCI will not trip with a normal short between hot and neutral, at least that’s not what its designed for, a normal breaker would trip in that case. But nowadays they combine GFCI and overcurrent breakers in one for some applications.

 

[ruki]

My guess is that if this was hooked up to a GFCI, it would have tripped when you reached into the tank.

The heater had an electrical conductor exposed to the water. The aquarium is made out of glass, which isn't a bad insulator. The water was acting like a capacitor which was partially discharged when you reached in. The ground was very possibly provided through your feet.

 

[essabee]

In my aquariums I have 2 carbon rods('D' cell battery rods from exhausted cells) one each at the upper rear corner soldered to the earth wire. The electric supply is 220V AC, and recently one of my heaters had cracked unnoticed and when I put my hand into the water I felt a tingling only, so I looked for electrical leaks and found the cracked heater.

 

[LS6 Tommy]

A GFCI will not trip with a normal short between hot and neutral, at least that’s not what its designed for...

Correct. GFCI's are commonly misunderstood. Here's a really good article about how they work and what they're supposed to do.

http://www.codecheck.com/gfci_principal.htm


Tommy <9))>>{

 

[vidiots]

GFCI outlets can fail in a way where they still appear to work correctly however the protection they offer is nolonger working as it should. This is why any that I have ever seen are equiped with a test button which should be checked periodically to make sure that it is still functioning as it should.

 

[ruki]

Also,

Sometimes power surges (lightning strikes, power glitches) can cause a false positive or even fry the GFCI unit. But, that sort of thing doesn't happen to frequently.

 

[tropicalfish]

Shorts don't trip the GFCI. Shorts trip the circuit breaker, but may kill the GFCI. Happened to one in our garage, waiting for my dad to fix it after finding out which circuit breaker switch leads to it.

 

[ruki]

Shorts don't trip the GFCI. Shorts trip the circuit breaker, but may kill the GFCI. Happened to one in our garage, waiting for my dad to fix it after finding out which circuit breaker switch leads to it.

Specifically...

(1) Shorts between hot and neutral don't trip the GFCI. Shorts between hot and ground do trip the GFCI.

(2) Loads greater than allowed for the breaker will trip the circuit breaker. Of the many ways to generate too great a load, directly connecting hot and neutral through a sufficient low resistance conductor, i.e. wire-to-wire short, may do it if the short has sufficient conductive capacity.

(3) If a hot-to-neutral short has borderline conductive capacity, it could act as a heating element and start a fire without tripping the breaker.