How bad is my electrical situation?

[thatmanMIKEson]

And another to add and repeat. If you don't have at least a GFCI of some type and do not want one I recommend getting a titanium grounding probe.

why a grounding probe?

I don't want to get into another debate but since this thread is all opinions: I wouldn't use a grounding probe without a gfci receptacle, this would alow stray voltage or faulty equipment that is leaking voltage to flow current to ground. it would be a good addition to a gfci though and probably cause the gfci to trip quicker and possibly more frequent if there is faulty equipment. does that make it safer? I guess it depends on what the "dangerous" situation is.

 

[jason2459]

Yes, everything I post is of my opinion.

A grounding probe can certainly aid a GFCI. Again, I'd rather a failure of this type to result in power being turned off. A GFCI is not required to use a grounding probe however and will help provide some protection.

An article from here posted a while back is a good overview.

Using Ground Probes in Aquariums

Why your saltwater aquarium needs a ground probe (or several). The piece is written by an expert electrician.

www.reef2reef.com

 

[Simon_M]

On the subject of electric shocks, using a ground probe and electric voltages in the aquarium, I have just done some investigation using an Oscilloscope.

I was adding extra equipment and noticed that I now get an electric shock if I touch the saltwater in the Sump. To resolve the problem I moved a Controller from above the Sump Area to the Chiller Area.

The Sump is humid and from time to time my Skimmer reacts and spits out saltwater everywhere. In the Chiller Area I have all my other electrical equipment and plugs/sockets etc. and it is dry.

I can use an earth grounded Titanium Heater or a two pin glass one that isn't earthed. UK voltage is higher at 230 volts AC. The electric shock is given when I don't have the earth grounded Heater. I also only get it when the Controller is in the Sump Area.

In both grounded and ungrounded cases I see a voltage in the tank of over 200 volts AC. As the previous link listed, this is by induction. With the Oscilloscope you can see the AC voltage and when it is earthed by a hand in the Sump or Aquarium, the voltage collapses to a lower level and the electric shock is only for an instant.

It is easier to trigger the Oscilloscope with an increasing voltage, so to get a picture of voltage vs time it can be triggered by a low voltage - hand is in the water to a high voltage when the hand is removed. So you can look at it in reverse of adding e.g. removing the hand. I might try to use a current probe to trigger on the instant the hand goes into the water.

With a Multimeter the current that is earthed can be measured. In my case it is about 0.2mA. That is about two orders of magnitude lower than that will trigger the House RCD (ground fault).

The grounded Heater does three things (other than heat the aquarium):

1. Grounds voltages induced in the Sump (so also the DT);
2. Masks any potential problems (adding new equipment - wrongly);
3. Triggers RCD (ground faults) if something powered electrical dropped in the aquarium (electric fan etc.).

So on balance it's a good thing. It is also worth remembering that your hands in an aquarium make a good earth, so it's best not to drop an electric fan etc. into the water if you didn't have a ground and RCD (GFCI). If the RCD (GFCI) happened to be faulty you also don't get much protection - so more than just a little zap.