Is this voltage too high

[ross94]

Hi, I was doing some work for my grandparents which involved fitting a blank plate to an old spur unit which supplied an outside floodlight which was still live and they wanted it disconnected, easy enough I got the job done but I was a little concerned about the voltage level, when testing my meter read 256v! which I thought was a little high. I measured some other circuits in the house and got pretty much the same reading 256v or 257v!.

As far as I am aware they have never reported any problems with their appliances but I think this voltage is little high. There is substation at the top of the road which supplies the whole street and it is about 200m away from the house so I wouldn't say it is exactly close. However there recently two tower block council flats demolished at top of road which this substation also fed. Perhaps this could of effected the supply voltage due to major decrease in load at the substation. Does this sound likely? or could a loose connection somewhere in the house be causing this high voltage.
cheers sorry if it doesn't make much sense its late and I am tired.

 

[Taylortwocities]

The normal allowed maximum is 230v + 10% = 253VAC. But with what were you measuring the voltage, was it a calibrated voltmeter or a £5 multimeter from Aldi?
Suggest you make another reading with a different voltmeter, or use a calibrated instrument. If the voltage is over 253VAC then it may be something for the DNO to investigate.

PS
A loose connection would result in less voltage, under load, not higher.

 

[ross94]

Hi there the instrument I used was my di-log combivolt 2 voltage tester, sorry not a multimeter

 

[Taylortwocities]

OK. I'd make test with a second instrument and then ask the DNO to investigate if the supply voltage is too high.

Do they suffer from short-life lamps?

 

[ross94]

Morning, I will take another measurement with a different instrument when I get the chance then get back to you, cheers. with regards to the short life lamps not as far as I know but I will ask them.

 

[winston1]

They will probably say they do as no one knows how long they should last. Modern CFL lamps are not so affected by voltage anyway, within reason.

 

[Risteard]

Suggest you make another reading with a different voltmeter, or use a calibrated instrument.

Bear in mind owing to the measurement accuracy and variations in temperature and all sorts of factors that even a calibrated and correctly performing instrument is only going to give an accuracy within a few percent.

 

[JohnW2]

Bear in mind owing to the measurement accuracy and variations in temperature and all sorts of factors that even a calibrated and correctly performing instrument is only going to give an accuracy within a few percent.

Indeed. Even a decent, calibrated, meter with a 600V AC range with 0.1V resolution will commonly have an accuracy quoted as ±1.5% ±3 digits (at a specified temperature and humidity), which means that a true voltage of 253V could be displayed as anything between 248.9V and 257.1V (at the specified temperature and humidity). With temperature/humidity variations (and maybe other factors), the range could be greater than that.

Kind Regards, John

 

[securespark]

This makes it awkward when you get readings that are borderline.

They could actually be outside the range required, thus not complying with regs.