Off-peak circuit not working - what next?

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JodieS

Active member
Joined
Nov 7, 2023
Messages
28
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Location
Birmingham
Hi folks,

New here so hopefully posting in the right place.

To cut a long story short, I am on Economy 7 and have two separate circuits wired into my meter which serve my flat - peak and off-peak. The only things connected to the off-peak circuit are two storage heaters and my immersion hot water tank. All three stopped working suddenly on Friday night (all other electrics are working fine). Everything looks normal externally and nothing has tripped in my consumer unit.

First thought was the meter time-switch could be faulty, so my energy provider sent out an engineer yesterday. He replaced my 20-year old meter with a new smart meter. I was hoping to wake up to a toasty warm home this morning... nope. The heaters are stone cold.

So I guess the problem must be to with the wiring in the off-peak circuit - either it's not receiving the message from the meter to tell it to come on at night, or something has gone wrong between the main switch and my flat. All of the meters and associated main switches are in a communal cupboard on the ground floor. Nobody else is having issues.

I will get an electrician to come out - but how can they test the problem outside of the off-peak hours? As there isn't supposed to be any power during the daytime anyway - it comes on between 00.30am and 07.30am.

A friend suggested getting a multimeter to test it myself during the night, so I can try that. Any other ideas?

Jodie
 
I know suppliers at least round here have had trouble getting 5 terminal smart meters , im hoping they have not put a 4 terminal in, as above a picture would be handy.
 
The off-peak main switch has an 80A fuse like this - is there any chance it has worn out? Or is that wishful thinking :sneaky: I expect it's the original one from when the flat were built 20-odd years ago.


20231105_125927.jpg

And here's my consumer unit:

20231105_175351.jpg
20231105_175356.jpg
 
I’m guessing the correct lives are in the new meter? Maybe worth getting a cheap no contact tester and hold it near the relavent isolator after midnight or when the switch supposed to close, is the meter set to 2 rate.
the other switch fuses need covers to cover those single insulated cables.
 
A no contact tester will also allow you to test if the cable after the fuse is live at the correct time , it’s usually a good idea to switch off before pulling the fuse.
 
Thanks for the advice :) That sounds like a plan. I did flip the isolator switch off before pulling the fuse compartment out - the angle makes it look like it says 'on'!

The meter is set up for two rates. I used a small amount of off-peak electricity last night running my washing machine (which is wired into the main circuit) and this has shown up on the Rate 2 reading, so the Economy 7 rate is at least kicking on on that circuit.

Will tell the management company that those other wires need covers!
 
@binky - the heaters just come on automatically at 00.30am as long as they are switched on at the wall at my end. I think the meter triggers the off-peak circuit to switch on?

@Murdoch - I think it is, as this morning it was showing that I had used 2kwh on the off-peak rate, which would have been my washing machine that I set on a timer to run during the night. But I will double check again tomorrow in case the 2kwh was clocked up during the meter installation process somehow (y)
 
Any competent electrician will be able to test, with dead testing of the loads (your storage heaters) are connected to your off peak CU, and your off peak CU is connected to the off peak switch fuse, and if the fuse in that is intact.

If all that is on order then it must be the meter not energising the off peak circuit.

But the fact the fault occurred before the meter swap and the meter swap was a "random equipment swap" to try and solve it, suggests it is unlikely to be the fault.

All that your washing machine metering at the cheap rate proves is that part of the metering is working. Ir does not prove if the meter is energising the off peak circuits or if the off peak circuits are fault free.

I suggest you try and find a competent local electrician.
 
Any competent electrician will be able to test, with dead testing of the loads (your storage heaters) are connected to your off peak CU, and your off peak CU is connected to the off peak switch fuse, and if the fuse in that is intact.

If all that is on order then it must be the meter not energising the off peak circuit.

But the fact the fault occurred before the meter swap and the meter swap was a "random equipment swap" to try and solve it, suggests it is unlikely to be the fault.

All that your washing machine metering at the cheap rate proves is that part of the metering is working. Ir does not prove if the meter is energising the off peak circuits or if the off peak circuits are fault free.

I suggest you try and find a competent local electrician.
Thank you - that's a really useful explanation of what could be going on.

I will do a bit of detective work tonight with my no-contact tester and then find an electrician - I'm in Birmingham if anyone reading this happens to be local!
 
Thank you - that's a really useful explanation of what could be going on.

I will do a bit of detective work tonight with my no-contact tester and then find an electrician - I'm in Birmingham if anyone reading this happens to be local!
Yes use that to establish if any power is going into and then out of the off peak switch fuse in the meter room, and then if any power is reaching the off peak consumer unit in your flat, and report back.
 
Well we have our answer - the meter switched over to off-peak rate at 00.30 as normal. The no-contact tester detected a live current between the meter and the main off-peak switch, and around the area of the switch itself - but then absolutely nothing coming out the other end of it. So it seems the buck stops with the main switch or the fuse inside it. Will get an electrician out to have a look. If the fuse has gone, we need to find out why (but it might just be old).

Now it's past my bedtime! Thank you all for the advice, I really appreciate it :)
 
Bear in mind it looks like twin and earth coming from the switch fuse , so i would think the left side of the cable should go live ,I have never known the switch to go wrong with those, thermal cycling can eventually kill as fuse ,just strange timing
 
Simple continuity check will tell you if the fuse has blown, you can do that with a torch lamp and battery. Fuses can blow due to ageing, and whilst that is rare, everything is cheap and nasty these days...
 
Thanks all, it is an odd one. Will try and test the fuse for continuity. I guess another explanation could be that something has come loose in the wiring between the fuse switch and my CU (maybe a mouse has chewed through something!) And if this happened during the day when the circuit wasn't live, this would explain why nothing tripped out? Will report back once an electrician has had a look...
 
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