Appliances in single phase property damaged by 415v

[UNG]

The supply voltage was too high. Yes I agree it was bad of them.

I meant anyone that's had equipment damaged. When I spoke to them I made it very clear that I was getting 415v at the supply.

Do you have any idea why the voltage would be so high?

 

[I Trippet]

Do you have any idea why the voltage would be so high?

Possible broken neutral, I couldn't investigate any further as it's the DNOs domain.

 

[UNG]

Possible broken neutral, I couldn't investigate any further as it's the DNOs domain.

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

 

[I Trippet]

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

So instead of getting personal, how about you tell us your theory!

Not quite sure how I can be "out of [my] depth" when the fault is on the supply side and acknowledged it's the DNO's responsibility and contacted them.

 

[LastManOnline]

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

Is that a windup? What more could he have done?

 

[UNG]

So instead of getting personal, how about you tell us your theory!

Try reading post #9 for a start or did you miss that
Checking the voltage a few other properties is all useful info to the DNO
You identified the local sub did you look around it for any sign damage
What voltage was on the stairwell lights

Not quite sure how I can be "out of [my] depth" when the fault is on the supply side and acknowledged it's the DNO's responsibility and contacted them.

You accepted the DNO's response that having isolated the property at the main switch it was safe, what about the meter was that isolated or did a 240v meter still have 415v connected to it creating a potential fire hazard, how many other apartments within the building and adjacent properties unknowingly also had potential fire hazards because of the over voltage
If the DNO didn't want to turn out I would have been talking to the fire brigade due to the potential fire hazards the fault might create I'm sure the fire brigade would get a response from the DNO

Is that a windup? What more could he have done?

No and see above

Maybe I approach things differently, over the years I have reported many network faults to the DNO's local to me, some of the faults are not that apparent but they are faults to which they respond and repair, yes I have a good working knowledge of three phase and how the DNO network is constructed and operates and it all helps when reporting a fault, had quite a few DNO guys on the ground comment that it's a pity more electricians are not as clued up and report faults

I suppose it was good that it was a TNS supply could have been very interesting on a TNCS Supply

 

[I Trippet]

Is that a windup? What more could he have done?

Yes clearly.

Should have broken in to the substation to have a closer look. Or maybe turn up to the DNOs head office with a loaded shotgun and tell them to send someone out or I'll blow their head off!

 

[ElectricSeamus]

That’s one very unhappy soul. Talk to someone, please.

 

[I Trippet]

Deleted

 

[I Trippet]

Deleted.

 

[UNG]

Should have broken in to the substation to have a closer look.

I don't recommend that but having a look to see if is secure or at the ground around the sub to see if has been recently disturbed could indicate that the earthing has been stolen

Or maybe turn up to the DNOs head office with a loaded shotgun and tell them to send someone out or I'll blow their head off!

But who would answer the next fault call?

I don't know your skill or qualification level as your profile doesn't tell me much.
I have tried to make you see the bigger picture of what the fault could do, it is harder on some occasions now to get the DNO to respond than it was 40 years ago for the reasons stated previously and the more information you have about the scale of the fault increases the pressure on them to respond by putting boots on the ground. I have had many arguments with the call handlers and asked for it to elevated to supervisors and managers and not accepted the refusal for immediate attendance so being able to stand your ground with the maximum amount of information you can find really helps

Look at the information you had
You have a neutral at 240v in one property in an apartment block how many other properties in the same block have got a neutral connection at 240v and what about the surrounding properties, knocking on a few doors and doing a quick mains check if the fault is present get them to call the DNO as well, as this is an apartment block and there is now a potential fire hazard in it should you evacuate the block while the DNO sort it out (more pressure or the DNO to respond)

May be speak to the DNO and see if you can meet up with one of their team and discuss their response to this fault and how if you have a similar fault you could better report it and get the DNO on site quicker, even using this thread as a reference and discuss the points raised

 

[Lister1987]

It should be noted that certain events are reportable to HSE under ESQCR - What must be reported? - ESQCR - HSE - https://www.hse.gov.uk/esqcr/what-must-be-reported.htm

Admittedly your run-of-the-mill sparky isn't listed, meter maids are however bit I would rather file a report as a competent person so that I know it's been done, rather than solely trusting the DNO, unless you can secure a (meaningful) unique reference from the DNO.

 

[UNG]

It should be noted that certain events are reportable to HSE under ESQCR - What must be reported? - ESQCR - HSE - https://www.hse.gov.uk/esqcr/what-must-be-reported.htm

Admittedly your run-of-the-mill sparky isn't listed, meter maids are however bit I would rather file a report as a competent person so that I know it's been done, rather than solely trusting the DNO, unless you can secure a (meaningful) unique reference from the DNO.

After a quick read of that it looks like the fault in this thread is not reportable

 

[Simon47]

So instead of getting personal, how about you tell us your theory!

Not quite sure how I can be "out of [my] depth" when the fault is on the supply side and acknowledged it's the DNO's responsibility and contacted them.

As said, knowing the basics of the distribution systems in use and the fault symptoms is useful even though they are out of your control.
That you measured 415V suggests a loss of neutral in the supply network. Turn to page 48 of the Wiring regs and look and figures 3.8 and 3.9 - from the sound of things, 3.8 for TN-S. Doodle in a star transformer for the supply - the local substation. Now consider what happens if the neutral cable between substation of consumer gets cut/broken. You now have a floating neutral, and the individual phase-neutral voltages for each phase will depend on the relative loadings.
In the traditional depiction of a star transformer, the arrangement of the windings corresponds with the phase diagram for the three phases. Once you lose the neutral, then the common point as seen by the loads will not be in the middle of the star.

In the best case, the loads are all the same, the phases are balanced, and there will be little difference to normal. But that's rare. Worst case is that one phase is heavily loaded, while the others are only lightly loaded. In this case, the phase-neutral voltage of the heavily loaded phase will be reduced, and those of the other phases will be increased - the neutral will drift until the currents are balanced.

Of course, as bulbs blow, fuses/breakers trip, and things generally let the magic smoke out - the loads on the phases showing higher voltages will reduce, and the imbalance will get worse. In extreme, you could end up with nothing on two phases, and a large resistive load on one phase - so one phase now gets very little because the neutral point is now pulled out to that corner of the phase diagram, while the other two phases now get 415V P-N (the neutral is now effectively one of the other phases).

Unfortunately, the <insert you own expletives here> who nick metal don't care about what damage they cause. So stealing a neutral earthing link for a substation might get them a tenner in scrap value, but cause many thousands in damage. The DNOs tend to hush up the problem, especially if someone is clever enough to get themselves injured or killed - the HSE people tend to take the attitude that the DNO should have done more to protect the sort of people who break into a locked compound, with security fencing, and with plenty of "DANGER OF DEATH" signs - and then interfere with what is obviously live electrical equipment ?

 

[Lister1987]

Unfortunately, the <insert you own expletives here> who nick metal don't care about what damage they cause. So stealing a neutral earthing link for a substation might get them a tenner in scrap value, but cause many thousands in damage. The DNOs tend to hush up the problem, especially if someone is clever enough to get themselves injured or killed - the HSE people tend to take the attitude that the DNO should have done more to protect the sort of people who break into a locked compound, with security fencing, and with plenty of "DANGER OF DEATH" signs - and then interfere with what is obviously live electrical equipment ?

I'd argue they should do more to discourage it, make the interior live so that they get a belt and think twice, or no more....either-or I'm not fussed, safe entry is granted by permit to work and remote isolation. Does make you wonder why they don't use vertical ground electrodes, as opposed to a horizontal arrangement that is easier to nick