westie101

Not really an issue for me, There was just a discussion on-going on a caravan forum about sites losing supplies due to overload and I wanted confirmation the the 16A supply wasn't really that but slightly higher.
I've had "words" with sites who were blowing out substation fuses who were not really interested as it only happens once a year so why should they do anything about it "well we can tell the caravan owners not too use too much but most just ignore us" Fine they are the ones that end up off supply!!

Hi

If the problem is serious enough to need action then using a current transformer and a simple circuit could be put together to operate some form of disconnection. Somewhere I may still have a circuit for this that was thrown together for a feed to a third party transmitter at a hill top site. The third party engineers were plugging heaters in when on site and on one occasion forgot to turn them off so the gentleman's agreement about comfort for engineers was torn up.

Regards

Bernard

Hi

PME v TT

Having experienced two serious neutral bounces at my previous house I am not being over cautious. We had PME at our previous house bu as it was from overhead distribution I added an earth rod sunk over 2 metres into the permanently wet ground next to the stream that formed our boundary. Our neighbour on the same network branch had an even larger rod + mat in what was the old mill race ( filled in but still very wet soil ). He logged a CPC at 30 volts above ground during that bounce,

I was involved in the aftermath of a lost neutral at a hill top wireless installation where bonding cables were scorched, and several aerial feeders damged by heavy currents to ground, The half mile of 3 phase + broken neutral at 230 was replaced by an 11kv route with a transformer at the hill top thus the neutral was local and less prone to fail.

In this cottage I have measured the CPC against ground and found 3 or 4 volts of very spiky voltage differences. ( hi impedance meter )

The situation between shop and cottage also has the added "problem" that they are not on the same network branch.

Best regards

Bernard

will be back there in 2 weeks, I will get back to you then. If you could e mail me at iceselectrical@aol.com for a more suitable contact then I can go direct if that is ok with you.

Westie, need to pick your brains on this as only seen it once before. Trying to ascertain the supply type of customers service head. It is not PME but does have a black cable coming from inside the hockey stick to the earth block. ELI is 0.29 so I can only summise that it is TNS with the balck cable being sweated on by the supply sparks in an area I can not get to or see. Can you from this description tell me what it is?
Jack C

Hi

A question about networks. Several nights there have been very noticable fluctations in the supply voltage in the local area. Almost all have been sudden drops in voltage lasting several seconds between 1 am and 2 am. I have never had meter handy when they happen but a comparison with a lamp on a variac suggests the voltage could be going below 200 in the worst cases. The DNO help desk did not have any information about these fluctations

There are no large loads on the local network as I am sure all houses of this circuit have gas heating. The only thing I can think of is that area wide night storage heaters are coming on and there is a delayed reaction at the tap changers on the 11Kv and / or 33Kv system.

It seems far to big a dip for it to be a result of cycle adjustment. Do they still adjust generated frequency to ensure that clocks dependent on 50Hz do the right total number of cycles each day ?

Regards

Bernard syemon.es@btinternet.com

PS did you get to meet liliana. sounds a nice girl.

Hi

The outside water tap on a PME system. A friend ( industrial engineer ) had his connected with a metre of plastic pipe inside the house but metal through the wall. He was told the metal had to be earthed ( bonded ? ) where in entered the house as it was an extraneous conductive service. A qualified electrician told him that.

Amplifiers. In the past year I have seen two amplifiers which had external connections and lethally bad mains power supplies. One, a mobile phone docking station, had the 0 volts to neutral and 18 volts derived direct from the live via a capacitor-resistor-zener voltage regulator. Reversal of live and neutral made the head set socket and docking station contacts live.

The other had a transformer with no separation between primary and secondary windings. Breakdown voltage depended on the varnish on the wire.

Both manufacturers are now on the banned import list but no doubt they will simply re-badge the equipment and import under a different name. The transformers are probably used by other manufacturers who may not be aware of the poor quality.

And yes both are from the far east where it seems a lot of very dubious and un-safe equipment is being manufactured.

Regards

Bernard

hi westie,
For the same reason, there are plenty of things about my activities which I do not 'bother' the forum about :-) Mind you, these comments are 'public'! If you want to PM me at any time, please feel free!
Cheers, John

Hi
That makes sense. Though it is several spans away from the pole where the service divides into two routes. Good excuse to go for a walk and see if there is another device on the other route.

Best regards

Bernard

PS have just been told that as TMA was not needed for the connection of my new supply it is very probable I will be refunded the TMA part of the invoice. It was the surveyor ( Western Power ) who suggested moving the connection point from under the drive way to under the grass verge to avoid having to have TMA.

Hi On a recent walk around the fields I notice what appears to be be a remotely controlled isolator fitted to a pole on a 11Kv line, The main box has 6 cables to the overhead lines which have in line insulators creating an isolation gap. It also has an indicator showing On or Off.

There is a small box fed from the up stream ( permanent ) side of the gap and a third box with an antenna on the top.

Are these a new idea. The only advantage in fitting a switch there is that it can isolate one small area of supply while leaving others with supply.

Westie,
As a DNO person can you advise me on this. Doing a PIR prior to consumer unit change and their is no green and yellow earth, just a black cable coming out of the hockey stick along with the incoming L & N. It then connects to the service head which I have not opened to have a look at. Any advise would be grateful. Its the black wire that is confusing me.
Jack C

Hi Off forum as it is a bit sensitive.
Western Power are quoting me to install a new supply to the cottage I have just bought. Until now power has been from the adjacent shop. It is a listed building and hence location of the meter is a compromise between BS7671 requirements, the conservation officers and DNO. Inside the kitchen and more than 600 mm from any pipe work is the ideal location but DNO will not install in kitchen on health and safety grounds. Which I do understand and partly agree with,

So I have a compromise If a recessed meter box was used in the kitchen wall it would then project 2 inches into the kitchen thus ample space for the tails to come out of the box inside the kitchen ( single brick wall extension to the stone cottage ). I think this would be safe and acceptable and allow external meter reading.

What is your opinion and are there any technical points I could raise to support my compromise. I am meeting conservation and planning officers on Monday. Then the NDO later in the week.

Best regards

Bernard

Hi Westie, Hope you are well. Would you mind changing your forum settings, as i'd like to send you a PM, but can't at the moment

Hi The story of our electrical service duct is more than I can post on a DIY forum as it involves discretion by the authorities involved. In the plastic drain pipe is the electric cable as planned. Later with permission of the network operator and BT the phone cable was run through the same duct. Both services come from the same pole. Several months later we had to install the pipe for the pumped sewage and more as a joke I said there was just enough space in the duct to push it through and save us digging a trench. I admit to being surprised when we were allowed by all three authorities and the building inspectors to put the sewage pipe through the duct breaking out a few yards from the pole to head of towards the main sewer.

Regards

Bernard