A/C inside Blower unit and ouside condenser grounding
My house is 20+ years old. While working in the main electrical panel, I've noticed the A/C wiring for the inside and outside units have their ground wire cut off at the entry to
The main panel, and therefore not connected to the ground bar. After further examining
The inside and outside units, I found that the ground wire was cut off at the entry
To the unit and not connected. The power to these units are 240v, therefore they
Have HOT: Red&Black, Neutral: White wires. I shut the power to these units,
And measured the resistance from the white wire to the chassis, it reads close to zero.
At this point I can only assume that since 20 years ago, there was no code for
Grounding the 240v units, the white wire is doing the job of both Neutral & Ground.
Question: By code Neutral & Ground are bonded together in the main panel. If
I try to add a ground wire from the main panel to these A/C units, how do I
Wire it in so that, there would be no bonding between Neutral & Ground
At the unit?
I am assuming that bonding Neutral & Ground any place other than main panel is
Against code, am right?
At this point I am not clear how these A/C units are wired internally for the
Neutral wire. Any idea how 240v A/C units are wired to handle the ground
And Neutral wire so that they won't be bonded together at the unit. Can I
Rewire the inside of these units to fix the Neutral & Ground issue
Or is this a task for the manufacturer of these units
And they should a have provided terminals for the Red, Black, White, Green.
These units are 20+ years old, and NEC was different back then.