Voltage problems?

[Heres_doe_]

I got shocked earlier and it was reading 25ish volts. I turned off things by things and found it to be the Nero 5. I turned everything off and still getting 9.5 volts. Is this normal and should I worry about the 9.5 volts. Will I have problems with the 25 volts as well? I will be removing the Nero for sure but not sure if it’s an issue to fish for the time being. They all look good and eating and no issues from what I see.

 

[betareef]

it was reading 25ish volts

What was reading this voltage, and what did you measure it with? Chances are it is a small induced voltage that will disappear if any load is present.

Do you use a safety protection device variously known as GFCI or ELCB - basically a device that trips if residual current to ground is detected? I would recommend this for any aquarium, and they are mandatory in many places in the world.

turned everything off and still getting 9.5 volts

Did you unplug everything?

not sure if it’s an issue to fish for the time being. They all look good and eating and no issues from what I see.

The fish are not grounded, so do not experience any voltage you measure with reference to ground.

 

[Heres_doe_]

Ok so starting with the highest volts of what’s giving off electricity is a few things. 2 wave makers and 2 heaters. And barely anything is the return pump which would be magnets working I think. I turned off wave maker and second highest volt is that. Turned another and then there it goes. Unplugged 1 heaters then that’s the volt. Unplugged the other. And lastly turned off return pump. Those are all numbers.

 

[betareef]

Ok so starting with the highest volts of what’s giving off electricity is a few things.

Yes but I meant, where are you actually sticking the probes to measure this? One in the tank water (or some conductor connected to the tank water) and one to electrical ground somewhere? If so, the fish will not experience this voltage as they are not grounded. In other words, what is the voltage reference, or what two points is it measured between? Voltage is a potential difference between two points of measurement, not an absolute. Additionally, if it is just stray inductance, grounding any metalwork in the aquarium setup, where you measure this voltage may make it all go away.

 

[Heres_doe_]

Yes but I meant, where are you actually sticking the probes to measure this? One in the tank water (or some conductor connected to the tank water) and one to electrical ground somewhere? If so, the fish will not experience this voltage as they are not grounded. In other words, what is the voltage reference, or what two points is it measured between? Voltage is a potential difference between two points of measurement, not an absolute. Additionally, if it is just stray inductance, grounding any metalwork in the aquarium setup, where you measure this voltage may make it all go away.

One probe in a ground and the other in the sump.

 

[betareef]

One probe in a ground and the other in the sump.

OK, If it were me, I would connect a test load between the sump water and the ground. Maybe use a old incandescent light bulb. Then measure the voltage again. It will probably have gone away. If not then perhaps you have a real electrical fault, but the way your readings change depending on what devices are turned on , is making me think is just stray induced voltage.

Unless the light bulb is glowing , replace it with a ground wire.

 

[apista]

Fish are above ground, your meter could read 240v and the fish still happy, put your hand in the tank a complete the circuit to earth and you will not be happy.

 

[DaJMasta]

If you actually got a shock from it, then it is probably worth dealing with the problem part (is it new enough to be under warranty?)

As for the voltage being present, not necessarily a problem. What's suggested above works fine (but who has an incandescent bulb these days?!), and the idea is to present that voltage in the tank (an electrically isolated system) with a lower resistance/impedance path to ground and then measuring again - if the voltage isn't reduced by much, the thing putting the water at potential can source a fair bit of current and definitely needs to be replaced (and as you have noticed, is a shock risk), but if connecting a load like that and remeasuring gives a very low or zero value, while the voltage is present, it's just induced from the cables and there's no real electrical path to transfer any meaningful current. When ungrounded, my tank often sits at a higher voltage than that even though there is no faulty equipment charging it up - it's more a factor of how many devices and how they're being driven.

If you have electronic parts handy, a similar experiment would be using a lowish value power resistor (maybe 500-10000 ohms or something) in series with the current measurement setting of the meter, one lead in the tank, one lead in ground. If it's reading more than a few tens of microamps (or a least significant digit on whatever range your meter can do), it has potential to be a problem and should be addressed. That would give you a more complete picture of what's going on electrically in your tank.

 

[betareef]

When ungrounded, my tank often sits at a higher voltage than that even though there is no faulty equipment charging it up

Heck, I've measured over a 90V on my own fingers when standing near an old fluorescent light tube