testing voltage at breaker panel


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Old 04-10-19, 03:44 AM
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testing voltage at breaker panel

Good day all.

I have recently retired from Europe (where I (re)wired some houses) to a "developing" nation which uses 220V and "American inspired" wiring (apart from the voltage). I was pretty good at at physics at school 50 years ago. I have no professional experience in electrical wiring anywhere.I was complimented on the quality of my work by government inspectors where local regulations required inspection.

I have a problem with the (single) wiring circuit in my new condominium. Since two professional electricians did some work during a fairly large renovation a number of lights no longer work and I can't get anybody else to trouble shoot.

I should add that the notion of colour coded cables does not seem to apply here. Many lights and sockets are wired with a single colour of wire so it is very hard to distinguish live from neutral. There is no earth/ground circuit in the condo. As I use UPS to protect my computers and TV I asked the electrician to set up earth connections to the metal socket boxes, and to the condo rebar where this was exposed.

So I have decided to attempt to fix the problem myself.

I use a fluke t90 voltmeter for testing.

My problem is I have a number of obscure voltages on my lighting circuit. 120V, 50V, 12V..... Some lights work. Some don't. My suspicion is that the electrician has wired the neutral of a different circuit to the wiring circuit by mistake.

A further difficulty I have is I am used to working with +220 and 0. However some people here who seem to know what they are talking about insist the local utility supplies +110/-110. Note however nobody uses 110V appliances here, everything is wired across the pins to get 220.

To test this I ran a single cable from a metal balcony railing (to act as ground) to the main circuit board light circuit. The result shows +220 on the live, and zero on the neutral which I think 100% proves I am at +220 and zero. Am I right?

Something that confuses me however is that the "continuity" light on the fluke comes on when I connect lighting circuit neutral on the breaker panel to the balcony railing. Does this sound normal? There is no wire connecting the balcony to an earth wire elsewhere.

Thanks in advance for any help. Please don't say find a competent electrician. There aren't any, as the many electrical fires attest.
 

Last edited by Pilot Dane; 04-10-19 at 05:32 AM. Reason: changed "circuit board" to "breaker panel"
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Old 04-10-19, 06:43 AM
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Hi, do you have a main service panel and meter? I would start there to determine what voltage you have there and test each circuit at a time, some pics of what you have there maybe helpful.
Geo
 
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Old 04-10-19, 06:46 AM
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If you need to use 220 volts, it does not matter whether it comes to you as "220 only" or as "0 and 220" or as "-110 and +110".

If/when you need to "ground" something you can take a single conductor bare or insulated wire, suggest #14 connected to the chassis of the equipment with the far end connected to the metal box of the breaker panel. String it any way/anywhere (route wise) you wish.

Whether or not you find that you get zero volts measured from the balcony rail to one of the two incoming current carrying conductors or you get zero volts from the panel enclosure to one of said conductors, do not connect those two items together (bond those two items) until you have learned the customs and codes of the country to find out whether such bonding is proper or required.

In the U.S. it is required to have two* 8 foot ground rods (at least 6 feet apart) installed near the panel where the power comes in and the rods are connected (using #6 copper wire) to the "neutral bus bar (terminal strip)" in turn electrically conected (bonded) to the metal panel enclosure.

* One under certain conditions.
 
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Old 04-10-19, 06:53 PM
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To test this I ran a single cable from a metal balcony railing (to act as ground) to the main circuit board light circuit. The result shows +220 on the live, and zero on the neutral which I think 100% proves I am at +220 and zero
Since you measured the correct voltage...... the metal railing must be grounded.

Something that confuses me however is that the "continuity" light on the fluke comes on when I connect lighting circuit neutral on the breaker panel to the balcony railing. Does this sound normal? There is no wire connecting the balcony to an earth wire elsewhere.
Read previous reply.

As far as I know...... the Philippines uses straight 220v...... no 110v at all.

However.... with a two wire service....It is possible to measure 110v from either the "hot" or "neutral" wire to ground based on the type of distribution transformer used. See in your case..... the "neutral" is not bonded to ground like it is here. That is also not a usable 110v. In your case.....you've already confirmed 220v to ground/neutral.
 
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Old 04-12-19, 09:05 AM
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The lower voltages you measure like 12V or 50V are very likely wires that are not connected to any hot or neutral, but are picking up an AC voltage from some hot lead by capacitive coupling. I suspect if you connected an incandescent light across such a wire and neutral, the voltage to neutral would go to zero
 
 

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