If national grid ignore voltage being out of spec and it damages equipment are they liable?

Chrysalis

Ectophile said:

The difference between 253V and 259V is only 2.3%.  So you'd need a meter more accurate than that to be certain that you are over-voltage.

Good quality professional meters can be that accurate, but cheap ones won't be.

I assume this is why they told me they going to send a voltage reader.

BarelySentientAI

Chrysalis said:

BarelySentientAI said:

prowla said:

252-259V: that's a 7V variation, or about 3%.

I'm amazed that the service can provide that stable a value over all of the infrastructure.

That's not a particularly stable voltage trace, if the measurements are only in the order of hours apart - but then voltages on some sections of the network are like that.

Chrysalis said:

Also ordered a volt meter, possibility might be a rogue , smart plug, socket or something in my home, so will check with that.

The closer (electrically) you can measure to the service head, the more you are measuring the supplied voltage (the regulated bit) and not the effect of something in your own system, although most things that could be wrong with your own system would either make the voltage jump to something stupid (>300V) or drop a little bit.

To clarify the voltage is moving within seconds or minutes apart, its not hours to get from 252V to 259V.

The pattern seems to be it creeps up slowly maybe 1V every 2-3 minutes on average but they can be much quicker like seconds apart, then when it peaks all in one go it will suddenly drop several volts.  It does multiple of these cycles per hour.

That raises immediate suspicions of a nearby large(ish) generator ramping up, with a transformer somewhere in the system automatically tapping down to regulate it.  Tapping wouldn't be local though as the transformers to LV are almost always off-load changers.

Unusual in a city centre though, and wouldn't be a new development.  I wonder if they've done something to kill the local inertia that means this pattern has arisen where before the grid was too 'strong' to change like that.

Does the pattern do the other direction?  Slow drop and sudden jump?

You can see from FreeBear's trace how 'noisy' voltages can naturally be, but if you have a regular repeating pattern there should be a logical source.

Chrysalis

I cant say for sure there is no sudden jumps as I am not plotting it, just that I havent seen it in reverse.

Chrysalis

Here is the update, as I had a DM asking me, so will tell everyone.

National Grid did fit a device next to my meter to confirm if it was an actual problem, they verified it was out of spec.  I was then informed they would plan a solution.

Then a while later which was a few weeks ago they informed me they adjusted the voltage on a local transformer and I do now see my average is now down to around 243v which is much better. 

Ildhund

One of the many advantages of having a modern smart meter is that it can support the measurement of multiple electrical parameters: mine does 37. It can also have built-in safeguards to interrupt supply if one of these - e.g. line voltage - strays outside preset limits. Mine can also trigger an alert over the home area network should a parameter measure outside desirable limits without being dangerous. Check the manual for your meter to find out how.  

Robin9

@Ildhund   Which make / model is that please ?    As a customer we do not have any choice of what the Supplier provides.

Ildhund

It's an Aclara SGM 1416-B. The manual for this type and many others is available from SmartMe's excellent site. If they don't have yours, try ManualsLib.