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I need the input from you electro-wizards. I'm in the Philippines, the power is 220v, 60Hz. In most places there is an absence of a ground line.

Lots of people in our area have issues of getting "zapped & bitten" when touching metal parts of table lamps, etc., and even resting on the palmrest of my (aluminum cased) laptop I get the occasional "bite"

To me it is bizarre, but if I connect ONLY the + lead of the voltage tester to the live line I get a power reading , usually between 40 - 60 volts.

I am at loss as to why I get a voltage reading when I connect only to the live line. If I test between the line and neutral I get the expect 230v.

We've ordered up a ground rod and will be driving this in next week to ground the neutral line and another one will be driven into the ground to act as a true electrical ground.

It isn't causing any great problems (yet), but I am trying to figure best how to resolve these issues.

Cheers, Tim

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  • \$\begingroup\$ Regarding the part of your question "ONLY the + lead of the voltage tester to the live line I get a power reading , usually between 40 - 60 volts.", are you saying the -ve lead of your voltage tester is not touching anything? Also is your meter measuring AC or DC? \$\endgroup\$ – Trevor Dec 12 '15 at 9:46
  • \$\begingroup\$ That's correct, the -ve is sitting on the counter not touching or connected to anything. It's measuring AC. \$\endgroup\$ – Tim Dec 12 '15 at 11:03
  • \$\begingroup\$ Copper plated fencing makes for a lower resistance ground grid, if buried near or bellow the water line. Hopefully the power provider has the generator frame grounded or isolated. \$\endgroup\$ – Optionparty Dec 12 '15 at 14:58
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You get voltage reading because it's AC, so it passes through air as through a capacitor, it means nothing. As for grounding, be careful, don't kill anyone with that neutral wire. Ground the cases and enclosures of your equipment and use earth leakage circuit breaker. Neutral may hold voltage by itself (referenced to earth).

Edit: it's residual current circuit breaker, apparently.

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  • \$\begingroup\$ Thanks. That's the path we've already begun to implement. \$\endgroup\$ – Tim Dec 12 '15 at 11:09
  • \$\begingroup\$ Forgot to mention, we've tested and compared the voltage difference between the neutral and earth/dirt (we've tested against a short Cu rod driven straight into the earth, rebar in the construction, and a few other points) and it always comes up 0v \$\endgroup\$ – Tim Dec 12 '15 at 11:19
  • \$\begingroup\$ The question is, is it actually always, guaranteed by something, or it's possible that one day under certain conditions someone will die. \$\endgroup\$ – Gregory Kornblum Dec 12 '15 at 11:21
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The DMM reading of voltage with one lead floating has no significance. You say that in your country there is absence of neutral and you will put a rod and connect to neutral. This can be dangerous, as you didn't described well the rules of your country. If the neutral exists, then it is grounded, if it doesn't exist you can have two lives instead (aka two phase system) or other circuit that doesn't allow a ground connection to one of the wires.
But let's say that you have a live + neutral: There is a must to have a grounded rod connection between neutral and rod. Extra you separate neutral and protection earth (PE) in one single point (in electrical cabinet near power meter) and you pull a third wire (PE, green-US, green/yellow-EU) to all sockets and appliances.

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ FYI: Philippines is a 220V and neutral. It's not two live 110's, or 2 phase. \$\endgroup\$ – Trevor Dec 12 '15 at 9:53
  • \$\begingroup\$ @Trevor, that's correct. \$\endgroup\$ – Tim Dec 12 '15 at 11:03
  • \$\begingroup\$ Marko, typical of the power companies here, they'll run a live and neutral and even if you don't have an earthed ground, they'll still sign off on the electrical permit. The house we are in has NO ground. It has live and neutral, nothing more. None of appliances are grounded as you cannot ground a single plug or appliance in the house the way it is wired. We're planning to run a ground wire into every power box and provide an external means to provide a ground (PS, I'm from Canada and used to using "normal" three wire wiring). \$\endgroup\$ – Tim Dec 12 '15 at 11:09
  • \$\begingroup\$ Let's suppose that you have all 3 wires already done in your house. The PE wire is connected to every metallic case when you plug the device. As you can see from my schematics, for example if the rod is ommited and if the neutral from distribution breaks (earthquake, flood,..) you will get the live on all metallic objects - this can be a death sentence. That's why is importnt to have your own ground - in some countries they just don't care if you don't have yours ground. \$\endgroup\$ – Marko Buršič Dec 12 '15 at 11:33
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I can't comment so I'll just leave an answer here:

There are two power delivery schemes in the Philippines:

  1. Single-phase (line + neutral), which is more common in the provinces (i.e. not Metro Manila)
  2. Split-phase (line + line + neutral), which is used by Meralco (Metro Manila).

I was confused by this too, honestly because I was expecting to measure 240 V between ground and line, however, I was getting 120 V for both line-to-ground measurements.

More info here: https://www.doe.gov.ph/sites/default/files/pdf/netmeter/manual-for-interconnection-of-rooftop-pv-v5.pdf (page 5, section 3.2)

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  • \$\begingroup\$ I live in a condo in Paranaque City, Metro Manila. my electrical outlets here reads 241VAC between two lines. it's 140VAC between the ground and one hot and 138VAC between ground and the other hot side. i rewired an extension cord wherein i cut and connect one of the wire to the ground male prong so that when i plug it into my 220 or 241 AC volt receptacle, i get 138-140VAC. i'm using it to power any of my 120VAC tools and appliances, so far so good. \$\endgroup\$ – renato reyna Dec 21 '17 at 12:07
  • \$\begingroup\$ @renatoreyna: That's an incredibly dangerous thing to do -- putting load current through a conductor that's intended to be used for protection only. You could be putting other people in your building at risk. \$\endgroup\$ – Dave Tweed Dec 21 '17 at 13:25

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