Brew12
Electrical Gru
I realize this is a very old thread, but I wanted to comment on it since it is still being referred to. I'm going to copy my post from that thread in the interest of saving time.
Let me see if I can set some things straight without getting too technical. We deal with 2 voltage sources in our tanks. One is induced and the other is fault.
And induced voltage occurs because alternating current is flowing through the tank (And yes, even DC pumps actually us AC current). The creates both an inductive and capacitive affect which allows voltage to be generated in the aquarium. This is very similar to how a transformer works. Unlike a transformer, there is a very high impedance between the electrical equipment and the water. If you add a ground probe to a the system it shunts current to ground. With the high impendence, it only takes a few milliamps of current to drop all of the voltage to zero.
Fault voltages are a different story. These occur when the insulation of an electrical device fails exposing an energized conductor to the water. This conductor is most likely copper. A copper conductor, carrying electricity and exposed to salt water, will corrode very quickly. This copper can adversely impact any corals and inverts in your tank. It can also cure Ich!
If you have a ground probe installed and using a GFCI it will trip the GFCI and de-energize the device. Not only are you more likely to notice the trip so you can investigate, but by de-energizing the fault it reduces the rate copper is released into the system
If you use a ground probe without a GFCI and the fault is bad enough, you will likely trip the breaker feeding the tank. There is a very low range of resistances where a ground probe can make this condition worse. Odds of it happening? Very slim, but technically possible. Since this condition is also more likely to speed up the failure mode it isn't likely to last long before tripping the breaker.
This is why I recommend running everything that gets wet on a GFCI with a ground probe. I do not recommend running everything on one GFCI for reliability reasons. It can be accomplished many ways. In your case, keep the MP40's off of a GFCI so if you lose your return pump it won't cause you to lose all flow. Your tank will be fine for hours this way.
Some other questions I have seen... If your titanium heater has a 3 prong plug you do not need a separate ground probe. You can plug in your ground probe anywhere. Even your neighbors house. It will still work. It doesn't matter where you install the ground probe. The water is conductive, as long as your return pump is running the entire tank is protected.
And finally, current won't flow through fish. They are less conductive than the water around them. This is why you can only electrofish in fresh water, not salt water.
Hope that helps!
Let me see if I can set some things straight without getting too technical. We deal with 2 voltage sources in our tanks. One is induced and the other is fault.
And induced voltage occurs because alternating current is flowing through the tank (And yes, even DC pumps actually us AC current). The creates both an inductive and capacitive affect which allows voltage to be generated in the aquarium. This is very similar to how a transformer works. Unlike a transformer, there is a very high impedance between the electrical equipment and the water. If you add a ground probe to a the system it shunts current to ground. With the high impendence, it only takes a few milliamps of current to drop all of the voltage to zero.
Fault voltages are a different story. These occur when the insulation of an electrical device fails exposing an energized conductor to the water. This conductor is most likely copper. A copper conductor, carrying electricity and exposed to salt water, will corrode very quickly. This copper can adversely impact any corals and inverts in your tank. It can also cure Ich!
If you have a ground probe installed and using a GFCI it will trip the GFCI and de-energize the device. Not only are you more likely to notice the trip so you can investigate, but by de-energizing the fault it reduces the rate copper is released into the system
If you use a ground probe without a GFCI and the fault is bad enough, you will likely trip the breaker feeding the tank. There is a very low range of resistances where a ground probe can make this condition worse. Odds of it happening? Very slim, but technically possible. Since this condition is also more likely to speed up the failure mode it isn't likely to last long before tripping the breaker.
This is why I recommend running everything that gets wet on a GFCI with a ground probe. I do not recommend running everything on one GFCI for reliability reasons. It can be accomplished many ways. In your case, keep the MP40's off of a GFCI so if you lose your return pump it won't cause you to lose all flow. Your tank will be fine for hours this way.
Some other questions I have seen... If your titanium heater has a 3 prong plug you do not need a separate ground probe. You can plug in your ground probe anywhere. Even your neighbors house. It will still work. It doesn't matter where you install the ground probe. The water is conductive, as long as your return pump is running the entire tank is protected.
And finally, current won't flow through fish. They are less conductive than the water around them. This is why you can only electrofish in fresh water, not salt water.
Hope that helps!
