Refrigerator display units with 4 wires. Blue, Brown, Yellow/green and Black.
The Black wire has been cut away at the plug end and not connected. The others are terminated conventially.
What is the purpose of the black wire and is the unit safe to use without it.?
No real help from the internet. One suggestion is that the unit is a 2 phase 110v appliance.
We have no other information (manuals etc).