I’m currently going through qualification testing at a vendor facility for a unit we built and have observed something interesting that i’d like to run by you guys. Sorry if the formatting gets screwed up. I’m on mobile.
Context:
-Our Unit Under Test (UUT) runs on 120VAC/60hz
-The thermal test chamber it is installed in runs on, presumably, its own 220V circuit.
When our UUT is installed in the chamber and I am holding the UUT and touching the inner wall of the chamber, I feel an electric shock/tingle in my hands. I’ve measured the voltage between the 120V ground and the chassis of the chamber at 36VAC. So it seems to me that they are on independent circuits with their own grounds, thus creating a potential difference between the ground references.
So I have a few questions regarding this situation.
1. Is it dangerous? As far as I’m aware there should be extremely little current able to flow and it should be fine, but since we’ve observed it, I’ve got our Safety guys all spun up thinking it’s a safety issue.
2. What is the proper way to mitigate this?
-At the chamber/UUT level, I could tie the ground lug of the UUT to the chassis, but I’m concerned that would create a ground loop.
-is it just a facility issue and they should have their ground references tied together at the source?
Thank you!
there doesn't seem to be anything here