An interesting read

[andrew1210]

yeah as well, there seems to be more of some colours than others on the poles. There are six wires and there is tape wrapped around the wires at the first pole.

Red --------
Red --------
Yellow --------
Blue --------
White --------
No Tape -------- (wire looks considerably thinner than others)

 

[westie101]

This seems to have all the symptoms of the network neutral being opened circuit between the houses and the transformer.

If three phase there would be voltage problems at the houses, if it is a single phase network that is quite possible

 

[mfarrow]

If three phase there would be voltage problems at the houses, if it is a single phase network that is quite possible

Explain. Surely there would be no problem of voltage difference with a good earth linking the houses with the source (which obviously there appears to be)?

If there were voltage problems, would this be noticable, or would any undervoltage caused by 'poor' earth successfully mask the problem?

 

[bernardgreen]

This seems to have all the symptoms of the network neutral being opened circuit between the houses and the transformer.

If three phase there would be voltage problems at the houses, if it is a single phase network that is quite possible

If the houses were taking roughly equal loads on the three phases then the neutral current if the neutral was intact would be roughly equal to zero and the houses would be getting roughly 230 volts ( or whatever the voltage per phase to star point was set to ).

While the neutral conductor may be open circuit there is a circuit through the ground by passing that open circuit and providing a path for any neutral current. So the effects of voltages is reduced by that alternative path helping to keep neutrals at the houses closer to the voltage ( ground ) of the star point in the transformer.

This [current into the ground] 3A is apparent in our house and 4 neighbours

So approx 15 amps of neutral equating to a average load un-balance ( ignoring phase vectors ) of around 3 Kwatts which sounds reasonable for domestic supplies.

 

[andrew1210]

OK so it gets worse

back from school a team of 8 SP men have been out all day and checked all 39 houses in the street... ALL HOUSES have current on Earth with highest being on our block near the top and transformer (3.5A today) and lowest at the bottom of the street 0.55A

SP have lost the schematics for our street and have spent the day with machines marking all underground cables out. There told us that the problem was now "much worse than expected" and emergency teams will work flat out to get this sorted, but they still don't give a clear answer what's up as they are "baffled" to quote.

They say that every house they checked (all that were occupied at the time) in our street, and other street, are all wired as PME, but system is TT for some reason!

Our house is now the "testing station" where SP are running back and forward after pulling house service fuses to see readings. It appears as a service fuse is pulled, the current is shared amongst those that are still on!

I'm now 99% confused!

edit: spelling correction

 

[andrew1210]

furthermore, SP have said the lines in our street are in terrible condition, with disintegrating insulators and sagging and almost touching wires, and spaghetti junction at about every change of direction.

They're just away, and are sending two cherry pickers tomorrow to check the lines and do emergency upgrade/tidyup/repair work as needed.

Will keep everyone posted!

 

[westie101]

The biggest problem is the inability to tell which way the current flow is, I have in the long distant past seen an odd situation where a terrace house with no earthing had a faulty kettle that was causing problems in the other 4 in the row!

Or reports of shocks caused by, again, no earth and incorrectly wired Christmas tree lights.

In both cases the original earth had been to metallic water pipes!

 

[andrew1210]

SP's latest is pulling services fuses in houses and seeing if the reading drops, which they will do in daylight tomorrow. Our house has been eliminated as the reading was still there after our fuse being pulled. we also have a new fuse carrier as the old one shattered! (now complete with no security tag )

 

[sparkydude]

Any updates on what SP have found out yet ???

Just curious as im sure you are to see what there explanation is for the current.


Nick

 

[OwainDIYer]

yeah as well, there seems to be more of some colours than others on the poles. There are six wires and there is tape wrapped around the wires at the first pole.

Red --------
Red --------
Yellow --------
Blue --------
White --------
No Tape -------- (wire looks considerably thinner than others)

One of the duplicate Reds may be a switched phase wire for street lighting - are there street lights on the leccy poles?

 

[andrew1210]

Hi, unfortunately, no update tonight, SP had a 'bigger emergency' to deal with today and were unable to spare any manpower to attend. They are coming back early Monday morning as apparently they don't work weekends! (hope I never have an outage on a Saturday)

@OwainDIYer:
Street Lights, used to be on leccy poles but not for the last 20 years, all aluminium, opposite side now. Having looked more closesly at the poles today the wires do look in awful condition with a lot of rust on the fixings on the poles..... then came the interesting part...... engraved on side (DOM: 1939) yep, they've seen better days, anyone think the fittings/fixings could be original?

Next big update about 5pm Monday!

 

[westie101]

anyone think the fittings/fixings could be original

Not think, know! We have stuff of similar age

 

[andrew1210]

btw, I showed 'the gaffer' that article about Net Current, "ahhhhh.... ehhhhhh.... ayyeeee..... we know what that is....... *silence*...... aye.... so.... tea time!"

 

[andrew1210]

anyone think the fittings/fixings could be original

Not think, know! We have stuff of similar age

Is this quite normal for the national grid! wasn't expecting that answer, I was about to contact the nation history museum if any upgrade was going to happen.

Transformer isn't that old though, it was replaced two years ago after someone shot at it with an air gun and it exploded

Oh theres many stories to tell up here..... like the time our house and our neighbours house's meters began running backwards after SP carried out some works.... got a good wee bit of free electricity from that as a gesture of goodwill... "we'll send engineers out tomorrow to correct" that night, fan heaters, extra long showers, oil filled radiators, tumble dryer.... lol

 

[westie101]

Though a few years ago I did come across a wood pole with a date of 1908 on it, it was also an ex GPO pole!