Whats this setup? 4mm from meter!?

[eveares]

Hi all, while visiting my grandma in the midlands, I noticed something a bit unusual - at least by todays standards!

Aside from having a radio teleswitch between the meter and the consumer unit, which i have never seen in person before than at her house; the wiring arrangements and the cable sizes used seem a bit unsafe!

4mm between the radio teleswitch and the meter, whats going on !?

As for earthing arrangements, T-N-CS from what i can figure. (shurley not T-N-C)

Below is a picture of how it is wired up from what i can work out, along with some other pictures including the radio teleswitch.

(Cable sizes that are not quoted in diagram are at least 10mm, what seems ok for the era when this was installed.)

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• eveares
• 6 Aug 2014
• 1

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• eveares
• 6 Aug 2014
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(Notice how PE and possible neutral conductor share same exposed terminal block as shown in my diagram.)

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• eveares
• 6 Aug 2014
• 1

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• eveares
• 6 Aug 2014
• 1

Regards: Elliott

 

[RF Lighting]

It is a switched neutral which when the teleswitch says it's time, sends a signal to the meter and tells it to change from "normal" rate to "off peak" rate.

 

[AndyPRK]

The 4mm is usually just a signal wire so the meter selects cheap rate

 

[eveares]

So out of the main incoming supply/fuse holder, how come there is only 1 thick cable. Does it carry both line and neutral conductors inside this thick cable coming out?

 

[RF Lighting]

Yes it's a concentric tail. The live is in the centre, with the neutral surrounding it. It's a tamper proof connector to prevent the abstraction of electricity before the meter.

 

[333rocky333]

Not seen that thing under the meter before, presume its some sort of meter fiddling prevention

 

[JohnW2]

Not seen that thing under the meter before, presume its some sort of meter fiddling prevention

Sort-of, I'd imagine. Is it not within that 'thing' that the concentric cable splits for connection to what looks like a standard meter (which could not accommodate concentric cable directly)?

Kind Regards, John

 

[Lectrician]

It's a concentric anti-tamper cable, designed to prevent electric theft. Fully moulded with a set size at the meter end to fit most meter centres, and the other end has a fixed moulded live and a longer neutral which is formed and cut (too many variations in cutout sizes).

Not seen these days, but used extensively in the 80s and 90s. Quicker and neater than tails too!

 

[ekmdgrf]

http://en.wikipedia.org/wiki/Radio_teleswitch

That's interesting. So the economy7 rate is turned on remotely by the energy supplier? Is it just me that's thinking, hmm, small transmitter placed next to the meter, broadcasting my own economy7 signal whenever I turned on the kettle/oven/frier/steamer/etc?

 

[westie101]

transmitter placed next to the meter, broadcasting my own economy7 signal

If you can find and duplicate the embedded coded signal!

 

[ekmdgrf]

transmitter placed next to the meter, broadcasting my own economy7 signal

If you can find and duplicate the embedded coded signal!

There must be some mechanism by which the code is generated and connected to a meter, so it may be possible to work out what it's meant to be.

Failing that, one can simply record and retransmit the whole transmission. Classic replay attack.

 

[JohnW2]

Failing that, one can simply record and retransmit the whole transmission. Classic replay attack.

That's assuming that (a) you can find the signal and (b) that the system is so unsophisticated that it will respond to an identical re-transmission of something it's already received. Even I wouldn't design a system with that large a moth hole in it - at the very least, I would expected there to be some (encoded) 'unique' date/time information in each transmission

Kind Regards, John

 

[westie101]

westie101 wrote:
Failing that, one can simply record and retransmit the whole transmission. Classic replay attack.

Er, no I didn't write that!! Bad John W2


ekmdgrf

If it could be done, don't you think it had? I can tell you it hasn't been done

 

[JohnW2]

Er, no I didn't write that!! Bad John W2

Apologies - quoting/formatting error that I hadn't noticed - now mended!

Kind Regards, John

 

[ekmdgrf]

If it could be done, don't you think it had? I can tell you it hasn't been done

How can you tell me that it has not been done? That's like when I was at school and the head of year assured me that he'd caught everyone who had played truant. The whole point of the exercise is not to be detected and so therefore the people that do it successfully do not show up on official records.

I do preemptivly conceed several points:

1) It's technically hard to do. If you have the skills you're probably too busy arguing about 2E0's lacking CW skills to have the time to do it

2) It's probably a lot easier and gets you a better cost reduction just to by-pass the meter

3) It could be detected by statistical anaysis, so you'd have to be very restrained as to how much you actually abstracted.

4) Again, it's not going to make you rich.

Or do you drive around with a DF rig looking for rogue transmitters?