Ground question

[MadFloyd]

I purchased a receptacle tester from Amazon recently and discovered that it reports an open ground on all the outlets feeding my equipment rack. However, these outlets are fed balanced power by Equi=tech transformers, so I'm wondering if the receptacle outlet just doesn't know how to read balanced power of if I truly have a ground issue.

One of the reasons I ask is that even now (in June) I have to discharge static before touching anything on my rack or Bad Things Happen.

As always, thanks in advance.

 

[amirm]

That's correct. The tester can't test this type of circuit. The ground on the output of the balanced power is floating halfway. It is +-60 volts from each lead. In a standard system, it is 120 volts from hot, and zero from the other.

 

[amirm]

Just to expand, this is how normal house wiring looks like:

Ground and neutral are at the same amplitude because inside the breaker panel, they tie together.

Balanced power does not have a shared point like that:

Now we have three distinct connection, with ground being the half-way point.

So a tester that looks to see if ground and neutral are similarly situated, would see the much elevated voltage between those two leads (roughly 60 volts) and thinks that the common connection between them has been lost. So it declares no ground.

 

[amirm]

BTW, this doesn't mean you have proper grounding. It just says that the tester can't be used for this task. You could carefully, if you know your way around high voltage, measure the voltage references to ground on the outlet and verify that it is 60 volts. Again, do not attempt this if you are not experienced with high voltage. You could risk your life or worse.

 

[MadFloyd]

BTW, this doesn't mean you have proper grounding. It just says that the tester can't be used for this task. You could carefully, if you know your way around high voltage, measure the voltage references to ground on the outlet and verify that it is 60 volts. Again, do not attempt this if you are not experienced with high voltage. You could risk your life or worse.

Thanks, maybe I'll get my electrician back to check it out. I've had nasty shocks that create loud pops just removing an LP from my turntable that shut down amps citing DC overload.

 

[amirm]

Thanks, maybe I'll get my electrician back to check it out. I've had nasty shocks that create loud pops just removing an LP from my turntable that shut down amps citing DC overload.

Ground in equipment is there for safety. It is designed to cause the breaker to open should the hot lead touch the chassis. It doesn't have an ability to remove static electricity unless you touch the chassis first. That is what I would do before touching the LP. That, and increasing humidity in the room .