it seems this question is rather common. I live in a rented appartment built 70+ years ago. Back then, the building was built on a budget, and it was code-compliant to have ungrounded 1-phase 120VAC outlets (still visible in corridors), and apparently still is. It is NOT a split 240VAC. However, somewhere in its life, the original 2-prongs outlets were replaced with 3-prong versions, but still ungrounded. Most probably it was an easy way to plug in modern electric devices.
Since there's no requirement from code to upgrade older installations, there's no way I could convince the landlord to rewire everything.
On the other hand, as the electrical grid isn't exactly reliable, I want to upgrade my small UPS from a 500VA unit to a 1500VA unit. The problem is, every manufacturer write in big, bold letters "Do not operate without a ground present, hae an electrician perform the necessary job", ignoring what's still code-compliant and all those places that people don't own. Is that a simple safety warning as I read most of the time, or a real functionality requirement? Only two loads have a grounding pin (a monitor and a switching power supply that powers all low-voltage peripherals) So that's problem #1.
Problem #2: A previous 1500VA CyberPower UPS I had used so far failed after just over 3 years of life (so convenient, the warranty is only 3 years sharp…) in a rather frightening way: a minute the general breaker trips. The following, the UPS doesn't kick in (a completely dead battery after 3 years after rather light usage? Please. - I deliberately oversized the capacity since the load is less than 100W). Unplugging everything, I try to turn it back on, and get a series of loud pops, hisses and foul-smelling smoke. As it was out of warranty anyway, I disconnected the battery and opened the UPS without touching any metal part, and out of the 8 MOSFETs, 6 were burnt beyond recognition. Could this has anything to do with ungrounded outlets? Or just a low quality UPS? To this day, CyberPower customer's service fails to recognize the seriousness of a UPS failing destructively in the absence of a load or grid issue. Dead batteries don't make a UPS self-destruct.
Third problem: Between ground from the UPS side (not the wall outlet side) and the hot water radiator, there's anywhere between 40VAC and the full 120VAC. That's a real safety hazard, but I don't know how to find the source. Another set of measurements I made: I don't have a plug tester, but measured the following:
- Hot-to-radiator: 3VAC
- Neutral-to-radiator: 108VAC
- Ground-to-radiator: hovering around 55VAC
Would it mean that:
The hot and neutral wire are reversed in the outlet
The hot water radiator pipes are used as either a neutral or ground return path?
What else?
I know that COLD water pipes were sometimes used as ground, but it is forbidden now. Never heard about HOT water pipes being used for anything electrical. Same goes for neutral-as-ground as it isn't a true ground.
UPDATE
And, I finally bought a GFCI tester. As expected, all outlets show “open ground”.
Voltage measured from the receptacle:
- Line-to-cold water pipe: 106VAC approximately
- Neutral-to-cold water pipe:
- 0V Ground-to-cold water pipe: 0V, but probably meaningless since ground is unconnected.
But something curious also: Line-to-hot water pipe and Line-to-radiator is also 106VAC. More of a concern, actually, as the UPS and electronic equipment sits very close to the radiator (not worried about heat though, as it’s right up against the colder wall.). And no, there’s no other space for it, and especially not the proverbial “closet”. I realize these measurements are completely different from the first ones.
I wouldn’t bet on the pipes being all-metal to the street. The landlord consistently replaces leaking and clogged pipes by plastic ones.
Testing the replacement UPS yields some interesting result: only the red light turns on, a combination that’s not documented. Sometimes, I get the two first lights turned on, but that is still illogical as it would require a connected ground to light up. (Note: nevermind the two last ones, I traced it down to a likely fried MOV inside one of the power bars. I removed them and all plugs tested open ground afterwards, just doesn’t light up the switch, though)
As for problem #2, it has been solved in the meantime: Apparently someone at CyberPower took notice of the seriousness of a UPS going up in smoke and agreed to replace the UPS out-of-warranty. The UPS isn’t the business-expensive double conversion model, so currently only runs through the battery when an outage occurs (line interactive). According to the manufacturer, AVR is mostly done without battery power.At the time of the UPS failure, there was no spike. I still have an incandescent light and it didn’t burn nor change in intensity as it does when the microwave is turned on.
