Faulty meter?

RF Lighting · 14 Nov 2020

Even if the teleswitch was connected up incorrectly and being metered, the amount of electricity they actually consume is tiny. I’d expect it use somewhere in the region of 2 watts compared with your 375 watts your meter is registering.

375W is not an insignificant load. Imagine six old fashioned 60W light bulbs on all the time.

Your teleswitch is connected up using terminals 1,2,4,7,8 (left to right) as shown on this diagram

Picture from John Ward’s YouTube video.

Pickup · 14 Nov 2020

Now I know why I can get Radio 4 when all the other stations drop out on my (crappy) car radio

SUNRAY · 14 Nov 2020

What is there is essentially the same in both, the only difference is the live feed to the Teleswitch in mine comes from the only main switch in the single CU. This is becoming a requirement for letting agents so there is a single point of isolation. In Pickups installation there are 2CU's and 2 main switches.

As has been said the thin blue wire is not a neutral, it is the signal from the Teleswitch to change the meter to cheap rate.

Originally the Henley as fitted in 1980's adjacent to the single split CU

was exactly the same configuration as Pickups installation using 2 CU's
Replacement 5+5 split board

SUNRAY · 14 Nov 2020

RF Lighting said:
Even if the teleswitch was connected up incorrectly and being metered, the amount of electricity they actually consume is tiny. I’d expect it use somewhere in the region of 2 watts compared with your 375 watts your meter is registering.

375W is not an insignificant load. Imagine six old fashioned 60W light bulbs on all the time.

Your teleswitch is connected up using terminals 1,2,4,7,8 (left to right) as shown on this diagram
View attachment 211430

Picture from John Ward’s YouTube video.

Thanks for the image RF, I don't think the Teleswitch in my pic has all of those terminals and Having confirmed with my friend the previous description seems to be correct which makes me wonder if there are variations in the layout of different manufacturers.

RF Lighting · 15 Nov 2020

I think there are basically two types. The one the OP has has an 80A and a separate 25A switching contactor which can be switched independently, and yours just has a single switching contact, so fewer connections.

It’s possible that different electricity boards used different makes. In my area (formally Yorkshire Electricity Board) I can only ever recall seeing the sangamo teleswitches.

RF Lighting · 15 Nov 2020

A quick google later shows that horstmann teleswitches were also used around here.

deano1712 said:
I have a 30A switch mounted alongside my CU. The wire going to the switch comes from the box that is mounted in the top right side of the meter box shown in the photo. Its the cable that runs vertically down on the right side.

Any ideas what the box is for? The switch doesnt seem to do anything.

Cheers, Mark

SUNRAY · 15 Nov 2020

RF Lighting said:
A quick google later shows that horstmann teleswitches were also used around here.

And that Teleswitch doesn't appear to have an RXL lead, perhaps there's an internal link option.

Pickup · 15 Nov 2020

Just back after doing some checks, meter readings have increased by 4, 1, 5 (day, night, total) units in 28 hours and the led is still flashing every 18-19 seconds.

104mA on the supply side of the fuse, 72mA between fuse and teleswitch, 34mA between fuse and meter.
6mA between teleswitch & c/u, 8mA between meter and c/u. (which should, I know, be zero but I’m putting it down to a cheap amp clamp & EMF interference).

I checked the meter at home and it seems ok (readings change appropriately when lights/kettle etc turned on/off.

Going to contact supplier and ask them to check the meter (£190 charge if it’s not faulty )

Thanks again!

PS The teleswitch is a Horstmann NU 069 09.

RF Lighting · 15 Nov 2020

Did you try putting some load on in the flat to prove this meter is definitely supplying your flat?

endecotp · 15 Nov 2020

Pickup said:
Going to contact supplier and ask them to check the meter (£190 charge if it’s not faulty )

Record a video showing the meter flashing and those low readings on the clamp meter and all the switches being off.
Try and get the supplier to view the video and express an opinion on it before you commit to the visit.

Note that it’s possible to correctly measure an AC current with a clamp meter even when no energy id being consumed, due to purely capacitive or inductive loads; the current is 90 degrees out of phase with the voltage. So your 8mA could be accurate.

winston1 · 15 Nov 2020

endecotp said:
Note that it’s possible to correctly measure an AC current with a clamp meter even when no energy id being consumed, due to purely capacitive or inductive loads; the current is 90 degrees out of phase with the voltage. So your 8mA could be accurate.

I know what you are saying but there is no such thing as a purely inductive load. All inductances have some resistance.

john4703 · 16 Nov 2020

I know it is dangerous and illegal but if I was in your situation I'd be considering pulling out the main fuse. That would give zero chance of any power going through the meter.

RF Lighting said:
Did you try putting some load on in the flat to prove this meter is definitely supplying your flat?

I know it is illegal and dangerous but I'd be considering pulling the main fuse and seeing if anyone complains that something is not working.
I remember many years ago turning off the main switch to a flat and then cutting the cable feeding the immersion heater. It was still live as it was fed from the consumer unit of the flat on the floor above. Such things can happen.

DetlefSchmitz · 16 Nov 2020

I, on the other hand, would not be considering such a stupid act.

JohnD · 16 Nov 2020

Pickup said:
Going to contact supplier and ask them to check the meter (£190 charge if it’s not faulty )

You could ask them to fit a 100A DP main switch (or a switchfuse if you prefer) downstream of the meter and beside it. In my district the supplier made no charge to pull their main fuse while I fitted my own, and return later in the day to refit and seal it). If you have the new tails and enclosure ready, or even in place, it is a quick job. They don't seem to mind having a main switch, or an MET, on the meter board, although they "don't permit" other Consumer devices.

Something that you can padlock off (or, if a switchfuse, take the fuse out. I have known people keep a blown fuse to put in things to prevent usage).

SUNRAY · 16 Nov 2020

john4703 said:
I know it is dangerous and illegal but if I was in your situation I'd be considering pulling out the main fuse. That would give zero chance of any power going through the meter.

I know it is illegal and dangerous but I'd be considering pulling the main fuse and seeing if anyone complains that something is not working.
I remember many years ago turning off the main switch to a flat and then cutting the cable feeding the immersion heater. It was still live as it was fed from the consumer unit of the flat on the floor above. Such things can happen.

I'll say just the opposite. Don't do it. Certainly not without the proper tools and lots of PPE.

I've been in several situations where power is fed from an unexpected source:
Working in a cottage kitchen I'd turned off main switch in the single CU and already cut through several cables then another went bang, it turns out the kitchen used to belong to the neighbouring property and some of the original circuit remained. Looking through the window we could see their freezer had gone off and they weren't due home for a number of hours.

And this one: https://www.diynot.com/diy/threads/tv-trips-neighbours-rcd.552549/page-2#post-4729417

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Faulty meter?

RF Lighting

Pickup

SUNRAY

SUNRAY

RF Lighting

RF Lighting

SUNRAY

Pickup

RF Lighting

endecotp

winston1

john4703

DetlefSchmitz

JohnD

SUNRAY

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