Strange off peak meter setup??

[ban-all-sheds]

By proposing that the outgoing meter tails be split, you are presumably assuming the at 1.5mm² cable originates from the same place (electrically) as the main tails, but that would make no functional sense.

It would if the purpose was to supply the boiler timeswitch.

There is only one pair of 'main tails' coming out of the meter, so they must always be energised, the meter (assuming that it is dual tariff) merely switching between tariff counters.

Indeed. And AIUI that is how some dual-rate systems are implemented.

A supply derived from those main tails therefore would not provide a peak/off-peak indication signal.

It's not supposed to.

The only thing which would really make any sense would be if that 1.5mm² cables comes from a (maybe just 'signal') output terminal of the meter other than the ones to which the main tails are connected. What do you think?

I think another thing which makes sense is that it's providing a supply to the boiler controls.

If I'm right, then (contrary to what you have suggested) there would be nowhere other than the meter from which that 'signal' feed could be derived.

But I have not made any such suggestion.

 

[JohnW2]

By proposing that the outgoing meter tails be split, you are presumably assuming the at 1.5mm² cable originates from the same place (electrically) as the main tails, but that would make no functional sense.

It would if the purpose was to supply the boiler timeswitch.

I'm lost. It would be no different from the 'always-on' supply that the boiler presumably already has.

A supply derived from those main tails therefore would not provide a peak/off-peak indication signal.

It's not supposed to.

Again I'm lost. What purpose do you think that feed has, then?

If I'm right, then (contrary to what you have suggested) there would be nowhere other than the meter from which that 'signal' feed could be derived.

But I have not made any such suggestion.

Did you not suggest that the supply in question could be derived from some other circuit in the installation?

Kind Regards, John

 

[Adam_151]

Its as rough as a bears backside in my book.

Should have had a set of 4 or 6mm insualted and sheathed tails into that spur, along with an earth of the PME block (the best upton to tidy it up)

Or a small consumer unit of the same make as the main one installed along side the main one (best option if you were wiring it from the start)


Anyone seen a set up where heating loads are supplied from the customers day load DB, but passed through a contactor fitted in/adj. this is fed from a 5A breaker in the same board, the DNO time clock provides a switched neutral to control it!

 

[JohnW2]

Its as rough as a bears backside in my book. ... Should have had a set of 4 or 6mm insualted and sheathed tails into that spur, along with an earth of the PME block (the best upton to tidy it up)

I agree - but that's not what the OP was asking - he was concerned about about having the cutout fuse as the only upstream protection for the 1.5mm² conductors (and that concern presumably wouldn't change much if the conductors were 4mm² or 6mm²).

Personally speaking (and, as you know, I'm no professional) IF it is just a 'signal' feed going through a 3A FCU, then my only real concerns would be the exposed inner insulation of the T+E and the absence of a CPC connection (and maybe a clip or two would make me even happier!). If those two or three issues were (could be?) addressed, then I don't think I would be unhappy to have a foot or two of 1.5mm² T+E protected 'only' by the downstream 3A fuse (plus the upstream cutout fuse) - which is what the OP was asking about. Whether one could address the 'single insulation' issue without using DI singles is a different matter - but they could probably still, in theory, be 1.5mm².

Kind Regards, John

 

[333rocky333]

Heres an old off peak contacter with 6mm control wires , in this instance they had no heating as the meter man failed to connect the control wires

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• 333rocky333
• 21 Feb 2010
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• 333rocky333
• 21 Feb 2010
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• 333rocky333
• 21 Feb 2010
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[mikeyd]

I'm lost. It would be no different from the 'always-on' supply that the boiler presumably already has.

John,

Sorry for part-quoting you, I'm loosing the will to quote.

As I understand it:

The meter is dual rate, but does no switching, and has no 'signal' output to say which rate is in use.
The tails from the meter go, (I guess) via a consumer unit or to (the element of) an electrical water heating system of some sort. These will be live 24/7.

Somewhere there will be a timer which only supplies the heating control circuit at off peak times.
However there will also be a switch next to the boiler, probably marked 'Boost' or similar, which bypasses the consumer unit and is fed from the FCU in the first post.

Westie said above, the 'boost' control supply could have been taken from the consumer unit, rather than the dodgy looking FCU to meter connection.

My assumption as to how this could have happened: Maybe there was a breakdown in communication since it was originally wired and they were waiting for the supplier or the DNO, or someone to buy the house and make a decision?
Maybe it was intended that the DNO was going to fit a teleswitch. The sparky laid a cable thinking that but months passed and when it did get fitted it was just a duel rate meter, so the meter bloke said 'I'll get someone to call you about a teleswitch but for now I'll put this cable here' 10 years later here we are..

 

[JohnW2]

I'm lost. It would be no different from the 'always-on' supply that the boiler presumably already has.

John, ... As I understand it: The meter is dual rate, but does no switching, and has no 'signal' output to say which rate is in use. The tails from the meter go, (I guess) via a consumer unit or to (the element of) an electrical water heating system of some sort. These will be live 24/7.

OK.

Somewhere there will be a timer which only supplies the heating control circuit at off peak times.

OK

However there will also be a switch next to the boiler, probably marked 'Boost' or similar, which bypasses the consumer unit and is fed from the FCU in the first post.

Perhaps. However, what the OP said was...

... there was a spur under the 45A switch labelled up as "off peak supply, isolate in meter box". I believe this just gives the boiler a live" supply signal at off peak times so it can heat water on an off peak rate.

... if that is true, then the supply we’re talking about has to be live only during off-peak times, not 24/7 - which it would be if the dodgy FCU is being fed from the main output of the meter (rather than an auxillary/’signal’ output).

Westie said above, the 'boost' control supply could have been taken from the consumer unit, rather than the dodgy looking FCU to meter connection.

IIRC, it was BAS, not westie. If it’s a 24/7 supply, that’s obviously true - it could be taken from anywhere in the installation - including the supply side of the (presumed) timer. However, it would then make little/no sense for that supply to be labeled “off-peak supply”, if it was live 24/7. More to the point, that 1.5mm² supply (with a 3A fuse) surely must be a 'control' supply/signal of some sort - it obviously could not provide the 9.5kW (electrical) boiler with 'boost' power itself.

My assumption as to how this could have happened: Maybe there was a breakdown in communication since it was originally wired and they were waiting for the supplier or the DNO, or someone to buy the house and make a decision? Maybe it was intended that the DNO was going to fit a teleswitch. The sparky laid a cable thinking that but months passed and when it did get fitted it was just a duel rate meter, so the meter bloke said 'I'll get someone to call you about a teleswitch but for now I'll put this cable here' 10 years later here we are..

Interesting speculation. Who knows?

Someone on-site could obviously tell us whether or not that supply is currently live during the daytime, but I imagine that the OP will probably not be going back.

Kind Regards, John