MultiMeter Help!

Uh hum... Actually, you can have voltage without current. Potential or Standing Voltage. ;D

 

OK, prove it. I can prove otherwise using ohm's law:

Volts = amperes x ohms

With Zero amps, you have zero volts. In order to have a voltage potential, there must be some interaction between two electrical fields, and when this interaction exists, there is a flow of electrons, hence current. If there is no interaction between two electrical fields, all measurements are arbitrary and meaningless.

 

Ok...I placed the black in the ground and the red in the sump and the meter went to 2. I had the dial set to ACV 10

Is this bad? Also should I do it in the tank or is the sump good enough?

I am not really having any problems with my fish!

How do I correct it? I know I need to unplug things one at a time to find the one thing giving me the current, but will a ground probe solve this for me also? Just buy one and put it in and I'm all set?

Thanks!

 

Check the tank too!

2 Volts is not bad, really...

I would run a ground probe with a GFCI for many reasons, though including fish health, safety to you, your tank and your home.

A ground probe will not fix an electrical device that is leaking voltage when it shouldn't. If you have devices that are leaking too much voltage, they should be replaced.

Stray voltage, as in your case, 2V in your sump can exist when your devices are working fine, and is a reason to have a ground probe for your fish's health. This stray voltage can be induced by electrical fields created by the pumps, lights and heaters. It's normal, but the only way to get rid of it is to electrically connect the tank water to ground by using a ground probe. There is no reason not to have a ground probe. Just make sure you get one that is made of titanium for aquarium use.

 

Static electricity is what he's referring to. It is technically a potential voltage and not a "real" voltage by definition, though.

 

Actually, there are several ways to describe it.

Take a AA battery for instance. It has no current unless a load is applied. Yet it holds a potential of 1.5 Volts.

In the instance of a tank. You can have a potential voltage just waiting for you to give it a path to ground.


For the OP:

2V is not bad. I would not worry about it too much. I do run a ground probe though. Better safe than sorry.

 

You're thinking of electric charge. This is different than Volts. You're confusing the definition of voltage. Determining Voltage requires a static electrical field and a dynamic field between two points.

During ESD (electrostatic discharge) a voltage and current are produced. Up until that moment, there is no measurable voltage (only theoretical) between the two points.

 

There is current here because the battery has an internal resistance. Although, there is very little current, there is SOME.

Remember ohm's law? It can be used this way too:

I = V/R

or rather:

Current = Voltage/ Resistance.

You see, when a battery has internal resistance, it also has current flow across the resistive path.

What you're referring to is an actual measurable voltage in the circuit (in this case the tank and all of it's components are an electrical circuit), that as you become a conductor to ground, there will also be measurable current. When the tank water equals ground potential (when you use a ground probe), there is no current flow.

I'm entertaining your efforts, but I still believe in the laws of physics.

 

But there is current flow.... It is just flowing to ground. Such is the point of a ground probe.

Sorry if my terms are a little off, but it has be a dozen years or so since college.

Imagine this....

You have a piece of equipment that has a small amount of voltage able to leak from it into the water. You have no ground probe or any other path to ground. That voltage is just sitting there..... Damn if the term escapes me.... waiting to find that path.
This would still be measurable voltage, yet have no current except through the multi.

 

Actually, there is no current flow here. It's not "flowing" to ground if ground and the water have the same voltage potential.

Think of two buckets on level ground. One bucket is filled with water, the other is not. Now, connect a pipe between the buckets that is at the bottom of each bucket. The water will "flow" from one bucket to the next until they each hold the same amount of water. When they each have the same amount of water, there will no longer be flow. When this equilibrium is reached, think of this as the voltage potential between the aquarium water and ground. There is none. Therefore, no flow.

Ohm's law comes into play again.

I = V/R

Since there is no resistance and no voltage between the aquarium water and ground, there is no current.

This seems to be the most common misconception about ground probes, that "current" is still flowing from the water to ground. It's not. It's now one and the same.

I only completed a semester in college about 13 years ago. I found I didn't need it much after that.