Getting electrocuted when touching metallic parts when a UPS is connected to the supply

Hello folks,

Stumbled upon this post while searching the internet for a similar issue that I was facing, and thanks to @PhilCorso 's suggestion, I've attempted to elaborate on the problem, provide various scenarios and its behaviors, and conclusion (including a very recent one I've come to) including the next steps I plan to take. Though I "think" I've found a way to eliminate the most dangerous problem of getting shocked (disconnected earth), I still have a few questions-
  1. Is it normal for the UPS to output half of the phase-neutral voltage to the phase-earth and neutral-earth when running on the battery? Or is it something I should be concerned about? The voltage measured in scenarios 2, 3, and 6 is what I'm talking about. The UPS in question is APC BR1000G-IN (India specific) (also known as Back-UPS Pro 1000 I guess)
  2. What would typically happen when appliances not requiring earth are connected between phase and earth instead of phase and neutral? Though I plan to check the same with the appliances connected in the problematic section, does anybody know for sure that this could be the reason why the post-earthed (to the faulty room) voltage on the earth pin raised from 1-3V to 6V?
    1. How I plan to check that is by testing the continuity between neutral at a socket and the non-phase lead connected to an appliance (when the phase to the appliance is turned OFF). Do I have to disconnect the power to avoid frying my multimeter?
    2. This may sound stupid, but I may have done this for a ceiling fan unknowingly while installing it due to a lot of wires that were there at the fan's hang point and I connected the supply based on a previously taped wire where the potential difference of 230V was present and now I remember that there were more than just 2 wires that were taped.
  3. Is the assumption that the Phase-Earth voltage would be the sum of the Phase-Neutral voltage and the Neutral-Earth voltage correct? Could it be that it is not measured by a regular multimeter? Earlier I had crazy low values (Phase-earth showed like 18v or something when my UPS technician showed it to be over 180V using the probes of his (more expensive) clamp meter) being shown by my multimeter, but today, the values seem reasonable (absolutely have no idea why).

Apologies in advance for the long post- but I believe the details will help you to help me better. Hopefully "Safety" is the right category for this post. :)Slide1.PNG
Liked the very graphic bits! Going slowly, disconnect all except the Power Service-Panel
1. Is the panel metal?
2. Are there 3 power service wires: Red, Blk, Wht?
3. Are Red, Blk called the ungrounded service wires?
4. Is there 240-Vac between them?
5. Is the Wht wire called the Neutral-Grounded Service Wire?
6. Does the Wht wire have 120-Vac between it and each of the Red & Blk wires?
7. Are the Red, Blk wires properly connected to the Circuit Breaker terminals?
8. Is the Wht wire properly connected to Neutral block terminals?
9. Are there Grn wires, called the Bonding-Jumper, within the Panel?
Next Step, UPS details: Mfg, Nameplate Data, and terminals identified!
I pray that your non-reply stance doesn't mean you've been electrocuted!
The following instruction will help reveal the problem!
1) Open all breakers in power-panel. 2) Close one powering the closest receptacle to the panel. 3) Plug-in the UPS (and Load)! Repeat for next receptacle and so-on, until you find the cause!

I recall a true story in my first job as an EE... The Plant's electrical system was 3-ph, ungrounded, 480 Vac. An electrician was directed to open a 3-pole, 3,000 Amp knife-blade switch located 10' off the floor! Using a safety pole, he opened the 3-blades, but with difficulty! So he climbed a ladder to exam the switch. He grasped the closest blade with one hand, then grabbed a 2nd blade with his other hand. The switch wiring was wrong, i.e., power into the bottom, instead of the top! Fortunately, although he had 480 Vac directly across the chest, he was knocked off the ladder, but he survived spending a few days in the hospital!
Now "The rest of the story"!
Nine months later, his wife had a baby... It took great deal of effort on my part to prevent other electricians wanting to do the same thing!
To all, Stay well !!!!
Phil Corso