Too high a voltage

[STI]

I know this is only just above the acceptable but it is above.

What can be done if a domestic single phase supply is reading too high. I went to a house today and the voltage was reading 255v.

Meter is calibrated

I checked at several sockets and light points all the same reading within 1v.

She is getting through ordinary bayonet lamps like there is no tomorrow.
Circuits all check out no problems with the IR or continuity so i am guessing its something to do with the high voltage.

Thanks for any help

 

[londonboy]

Erm DNO?

 

[STI]

Erm DNO?

Thought that but was interested in knowing what they can and do do

 

[londonboy]

Not much, not much.

 

[pjcomp]

Has she got a substation at the bottom of the garden?

There's been advertising lately for a system that claims to reduce the incoming voltage and thereby reduce usage (and thus electricity bills) - the name escapes me, but I'm sure I've seen it advertised in Professional Electrician and discussed on other forums, though damned if I can find it ... How good it is at reducing bills is anyone's guess (snake oil anyone?) but if it really does reduce the voltage it could be just what your customer needs.

Anyone else recognise what I'm talking about? If I can find it I'll post back here with the info.

PJ

 

[pjcomp]

Well I've found somehting like it, called PowerPerfector (www.powerperfector.co.uk) - though this isn't the one I was thinking of .. This is commercially targetted and needs a 3-phase, 400V input. The one I mentioned earlier was definitely aimed at the domestic market.

PJ

 

[toasty]

There is a way of reducing incoming voltage in a house by using a high current but relatively low voltage transformer (say 5-10volts) with the primary connected over the mains supply and the secondary in series with the supply, but wired such that the 5-10v from the transformer secondary is subtracted (not added to the mains voltage)

If you think about it, it's a simple and obvious solution, but not one I've ever seen in practice I should add.

5v 100amp transformer is only 500VA so nothing massive really.
I suspect this is what the product you describe has inside it.

 

[pjcomp]

Now I've found it - it's called vphase, website at http://www.vphase.co.uk/default.aspx. Claims to optimise voltage use and reduce it to 220V incoming.

PJ

 

[flameport]

That vphase effort has been discussed here before. It won't save 10% or anything even near that.

It doesn't work with heating loads (i.e. all of the high use appliances), it cannot possibly work with switch mode power supplies (that will be 99% of all electronic equipment) and the alleged savings conveniently forget to mention the £1k or more it will cost to have the device installed.

 

[STI]

Thanks all for the replies.

The place is an apartment in an old converted house. Its the middle one of three one on each flooor. I am going to measure one of the neighbours voltages to see if they have the same. No sub station at the bottom of the garden (in fact no garden).

Is it worth telling the DNO also could this be the reason why the lamps are blowing so frequently. I am told a least one a week and there are only 12 in the whole apartment.

 

[efiste2]

Checking neighbours volts is a good move mate, If they too have the same problem ring the DNO.
A lot of local 11000/415 Transformers have Tap changers inside to adjust output, and perhaps the local one to you has been raised, or could be lowered. When we energise a new local transformer, before connecting to the local LV network we check the output volts, and if it was pushing 255 Volts we would tap it down. Usually 248 Volts we would connect as local load would fetch it down. But 255 is very high!!!

 

[STI]

Checking neighbours volts is a good move mate, If they too have the same problem ring the DNO.
A lot of local 11000/415 Transformers have Tap changers inside to adjust output, and perhaps the local one to you has been raised, or could be lowered. When we energise a new local transformer, before connecting to the local LV network we check the output volts, and if it was pushing 255 Volts we would tap it down. Usually 248 Volts we would connect as local load would fetch it down. But 255 is very high!!!

Thanks Efiste2 a great help. Ill check the neighbours and see if a call to the DNO is needed. 255V was the peak i had a couple of points hovering between 253 and 255 but still right on the limit.

 

[crunchynut]

STI,

I posted similar recently: //www.diynot.com/forums/viewtopic.php?t=243505

Hope it helps.

 

[STI]

Crunchynut thanks. I thought i had read something in the recent past but i searched on too high voltage and didnt get to your post.

I guess you haven't been back yet to see if any changes. Did the DNO do anything or didnt you get in touch.

 

[plugwash]

There is a way of reducing incoming voltage in a house by using a high current but relatively low voltage transformer (say 5-10volts) with the primary connected over the mains supply and the secondary in series with the supply, but wired such that the 5-10v from the transformer secondary is subtracted (not added to the mains voltage)
.

Be VERY careful if you build something like this. Should the primary of the transformer become disconnected the voltage on it could in theory rise to 10KV or so (though in practice it is likely to destroy the transformer before it gets that far) because of this you absoloutely don't want any fuses between the primary side of the transformer and the point where the secondry/load tee off.

To protect against faults in the transformer you probablly would want a thermal cutout mounted on the transformer and connected so it disconnects the whole arrangement from the mains.

I also think the whole think should be mounted in an earthed metal case with appropriate warnings on the cover.