Possibility of electrocution?

[aquaman3000]

Hopefully some electrical guru can help ease my mind. I am setting up a freshwater planted aquarium and intend to use heating cables submerged in the substrate. Is there any way whatsoever I could be harmed by the following.

The cables are powered by a step down isolation transformer with 115 VAC input and drawing 2.46 amps on the input side with a max load of 270 watts protected by a 4.0 amp super time - Lag TT fuse.

The transformer powers a heavy duty submerged silicone cable manufactured by Dupla at 48 volts and 6.43 amps on the output side.

The statistics I have read indicate the skin give between 2000-50000 ohms of resistance, but a inside the skin only provides 500 ohms. It seems to me that should the cable become cut and exposed, and I happened to stick my arm in with a cut, I would potentially be able to run 96 milliamps through my body (48 volts / 500 ohms)? I have heard that 30 milliamps through the heart can cause cardiac arrest. Does this seem like sound reasoning. The product in question guarantees absolute safety, but I would appreciate opinions by those with extensive electrical knowledge.

Finally, I do use a GFCI, but as I mentioned, this is an isolation transformer. I also will be using a titanium grounding probe.

 

[shavo]

hey, 48 volts aint so bad, I would trust it if it says it's safe and it is it's intended use, why not? now my heater on the other hand i just took out of the loop. It was my back up heater, everytime it kicked on I got it good. funny how fish don't look affected from electricity?? how come??

 

[Anonymous]

fish are not grounded.

If you could levitate you could grab a live wire with little problem. Same reason birds can perch on power lines.

 

[Anonymous]

as mentioned, 48 v is not that bad, if it is over 55v (somewhere in that neighborhood :?), it can harm you for sure.

 

[Anonymous]

Well if the cables are insulated, then should be no problem, however if there's any cracks in the insulation (or the wiring isn't meant to be submerged) I would definately think about other heating alternatives.

 

[t gallo]

Plug it into a gfci protected circuit only.

 

[das75]

If the unit is not certified (UL, CSA etc) for use in water, stay away. Wouldn't trust my life and others by running numbers through Ohms laws.

Could a mat be made and sit under the tank rather than in?

 

[aquaman3000]

Thank you for the responses. The product in question is specifically made to be submerged in the substrate of aquariums by a company from Germany. Their product marketing states that it is absolutely safe, however, this is an older model, and their newer replacement product is nearly identical, except that it only uses only 24 volts in the submerged cable. I also make a mistake in the original post, it is actually 42 volts in the submerged cable not 48. I would use the newer product, except that I am having a hard time getting it imported to the U.S. and it is very expensive and I already have this model. I have also been informed that an isolation transformer defeats the GFCI, which I already suspected.

Frankly, this product is no different than placing a glass heater into the tank, because if the glass breaks, it would actually be much more dangerous at 120 VAC @ 60 Hz. Instead, this product has a heavy duty silicone protected cable that is buried in the substrate and uses a safer 42 volts, but I can't put as much trust in the insulation of a submerged cable, nor could I see it as I could with a broken heater.

I think ultimately, based on responses I have received here and elsewhere, I will try to get the newer 24 volt cables before I consider making use of these.