Supply Voltage High

[petercsea]

Following recommendations from the people here I was earthing the shower units and the ceiling lights. Cut the power did the job and reconnected. Used a multimeter to check voltages etc. Supply volatge 354 Volts from Active to Neutral and Earth to Neutral on three power points two circuits. I don't think that it should ever get this high or should it? Never seen it before.

[Crossy]

OK, is that a typo, THREE HUNDRED and something volts?

If it were 250V I'd say it's high but manageable.

Record the voltages L-N, L-E, N-E and let's see what we can do

Should be roughly:-

L-N = 220V

L-E = 220V

N-E = 0V (can be a small voltage with no problems)

Edited May 7, 2008 by Crossy

[Jingjok]

I agree with Crossy.

At 300+ volts it's either a typo, a dodgy multimeter or you have done something supremely odd and arranged to have two phases present at a normal (2 or 3 pin) power socket. Mind your fingers, and your appliances! I mean it, please be careful, a trans-cardiac shock across phases is lethal.

Here in Phuket I today have 229V phase to neutral, and 398V across the phases.

BTW, 220V sounds low to me. Where are you Crossy? I think Thailand is supposed to be 230V. But the voltage here does go up and down like the proverbial whore's drawers

And, Peter, you don't really mean you have full mains voltage measured neutral to earth (ground) do you? Taken what you have typed literally, the only explanation I can think of is you have measured at a three-phase socket, with no neutral or earth present. Like one might plug a motor into in a factory.

FYI, on an American socket, as are used here in Thailand, the slightly wider pin is the neutral, connected to the white wire; the narrower pin is Phase(Live), connected to the black wire.

Old-skool Electrical Brits (like me) absolutely hate these colours. For example, being forced to connect a red flex core to earth is the stuff of nightmares

[petercsea]

OK, is that a typo, THREE HUNDRED and something volts?

If it were 250V I'd say it's high but manageable.

Record the voltages L-N, L-E, N-E and let's see what we can do

Should be roughly:-

L-N = 220V

L-E = 220V

N-E = 0V (can be a small voltage with no problems)

Not a typo Crossy. Reading it again right now:

L-N = 345V

L-E = 346V

n-E = 0 V

Using Digital Clamp Meter with leads. No facility on meter to calibrate. Haven't had any probs previously. Normally 230 V

[Tywais]

BTW, 220V sounds low to me. Where are you Crossy? I think Thailand is supposed to be 230V.

220VAC is standard for Thailand > http://www.kropla.com/electric2.htm

However this link indicates both 220 and 230 are correct > http://www.m-i-link.com/outstation/voltFreq.asp

.

[Crossy]

Are your lights working OK, ie not incredibly bright like being inside a lighthouse (before they go off with a pop that is)?

Assuming they are I suggest a new battery in the multimeter as a first stop, some do give odd readings when the batt gets low

Edited May 7, 2008 by Crossy

[longball53098]

OK, is that a typo, THREE HUNDRED and something volts?

If it were 250V I'd say it's high but manageable.

Record the voltages L-N, L-E, N-E and let's see what we can do

Should be roughly:-

L-N = 220V

L-E = 220V

N-E = 0V (can be a small voltage with no problems)

Not a typo Crossy. Reading it again right now:

L-N = 345V

L-E = 346V

n-E = 0 V

Using Digital Clamp Meter with leads. No facility on meter to calibrate. Haven't had any probs previously. Normally 230 V

Sorry,,can someone explain what a "Digital Clamp Meter with leads" is? Is this a type of clamp on amp meter and multimeter? Any link to the product I can see a photo and spec?

Thanks

[Crossy]

Sorry,,can someone explain what a "Digital Clamp Meter with leads" is? Is this a type of clamp on amp meter and multimeter? Any link to the product I can see a photo and spec?

I'm assuming he means something like this http://www.directindustry.com/prod/b-k-pre...583-350577.html clamp on ammeter that has DMM functions too, or is it a DMM with a built-in current clamp?

Obviously I could be wrong.

Edited May 7, 2008 by Crossy

[soundman]

House 216V- 224V (offthe street)

Factory 234V - 239V / 388 - 420V (my own 22kV-380V)

354V would be between the phases on a slightly under 220V standard supply. If you had two of the main phases, instead of a neutral connected to your supply, and not earthed, it is possible, however, at that point a fair amount of your appliances are going to start meltdown.

300+ Volts - Something is wired up in an odd arangement for a domestic supply. Cheap transformer?

Soundman.

[petercsea]

Are your lights working OK, ie not incredibly bright like being inside a lighthouse (before they go off with a pop that is)?

Assuming they are I suggest a new battery in the multimeter as a first stop, some do give odd readings when the batt gets low

Thanks Jingjok and Crossy,

Immediately switched off power. Headed into town to your favourite shop and purchased another "thru Mae Sai" special. There most definitely isn't 2 phases connected and the house is the 7th of 10 from the transformer and no houses were flaming!

came back and re-measured:

L to N =231 V

L to E = 230 V

N to E = 0V

Then put a new set of batteries into the old and yes it was the old batteries.

Mea culpa!

[Crossy]

came back and re-measured:

L to N =231 V

L to E = 230 V

N to E = 0V

Then put a new set of batteries into the old and yes it was the old batteries.

Mea culpa!

Looks like it's wired OK

Glad it was a meter problem not something more serious. Been there, got the T-shirt.

Edited May 7, 2008 by Crossy

[Jingjok]

Well done for sorting it. I've done this before - put too much trust in instruments over common sense and intuition.

Nothing to be shy about: the same thing has caused pilots to deliberately crash perfectly good aircraft!

[dotcom]

If your ground is working properly you should be able to read some value between neutral & earth. Put your multi meter to the lowest setting for AC voltage & try again. On mine it will fluctuate wildly at around the 4 volt level. BKK.

[147SAG]

If they took the wrong tap off the transformer in stead of 208 volts could be 600 volts that would be 347 volts from one phase to ground. But then you would have blown the lights in the house and alot of other things as well.