Ungrounded apartment - how does neutral to ground vs. neutral to load

Thread Starter

BangkokBob

Joined Jul 1, 2021
2
Greetings from Thailand - the land of only 2 wire electricity. My apartment is only wired with 2 wires; I added a third grounding wire that went to the buss on the panel board (which looks like it's connected to a water pipe). I get 233 VAC Load to Neutral, 183 VAC Load to Ground, 56 VAC Neutral to Ground. What is going on? The 2 grounding measurements equal 239 VAC (so that is in the ballpark); but isn't this strange. Can you ground (or earthing as it's called here) just one apartment in a building? With that much Voltage around, is it dangerous? My shower has an instant heater - probably a good place to get a shock. I do get various shocks and hums from various metal touched, especially at the split unit air conditioner. Thanks so much for the education, I read lots of search pages; but looking for someone with real experience. Thanks in advance.
 

Papabravo

Joined Feb 24, 2006
17,297
So Earth and Neutral are not at the same potential anywhere close by the building. AFAIK that means the Earth wire you added serves no useful function. In a 2-wire system you should be able to touch either Hot or Neutral without getting a shock, because there is no path to Neutral or to Earth.
 

nsaspook

Joined Aug 27, 2009
8,907
My experience from living in that part of the world was to buy transformers to isolate the two wire ungrounded grid power and form our own separately derived safety grounded neutral 240VAC system for inside. We used the isolated power for things (small appliances, hifi equipment, receivers, ...) we were likely to touch and maybe get shocked with a direct grid power connection. High power loads were still connected directly to grid power.
http://www.sacthailand.com/transformer_blitz.html
Transformer_BritzP-1.gifTransformer_BritzP-2.gif
 

Thread Starter

BangkokBob

Joined Jul 1, 2021
2
My experience from living in that part of the world was to buy transformers to isolate the two wire ungrounded grid power and form our own separately derived safety grounded neutral 240VAC system for inside. We used the isolated power for things (small appliances, hifi equipment, receivers, ...) we were likely to touch and maybe get shocked with a direct grid power connection. High power loads were still connected directly to grid power.
http://www.sacthailand.com/transformer_blitz.html
View attachment 242577View attachment 242578
Being from Thailand - you have the experience; and being a bit of an audiophile myself - your web site was very interesting. But I have gotten a 'buzz' from the split unit AC - and these transformers are more in line with audio equipment (from what I gathered). The AC technician came and took out the Safe-T-Cut (an added circuit breaker box) and now I'm getting 230 VAC and 95 VAC and 8 VAC between Load, Neutral and Ground. Those numbers are not adding up - are they? But a huge change from before. I will contact SAC Thailand direct for a transformer to isolate my stereo equipment.
 

nsaspook

Joined Aug 27, 2009
8,907
Being from Thailand - you have the experience; and being a bit of an audiophile myself - your web site was very interesting. But I have gotten a 'buzz' from the split unit AC - and these transformers are more in line with audio equipment (from what I gathered). The AC technician came and took out the Safe-T-Cut (an added circuit breaker box) and now I'm getting 230 VAC and 95 VAC and 8 VAC between Load, Neutral and Ground. Those numbers are not adding up - are they? But a huge change from before. I will contact SAC Thailand direct for a transformer to isolate my stereo equipment.
NewMosquitosTraveLodge-sm.jpg
We were in Pattaya City, on the gulf in 70's, 80's but the AC power was pretty much the same then, as now it seems.
 
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