Economy 7 - need confusion clearing up please!

Simon0211 · Apr 9, 2019

We have an Economy 7 meter and tariff.

There are 2 separate fuse boards and one meter with the dual rate on.

Am i right in thinking that ANY electricity we use at night will be cheaper as the meter has a 'timer' to switch to the cheaper tariff? If so then why is there the need for a separate economy 7 fuse board?

We have storage heaters that run off that board as well as the 'normal' board - presumably they store from the night board and can be boosted from the day, but if ALL electricity is cheap overnight then why the need for a separate board?

If someone could let me know i'd appreciate it!

Thanks

littlespark · Apr 9, 2019

Your storage heaters and the board they come from are timed or remotely controlled to only come on at night. All electricity is cheaper through the night, but you don’t want your heaters powered up during the day on expensive rate.

Sometimes the e7 board and normal are combined into one board, but they take up a lot of space and still require 2 sets of “tails” - the thick cable that connects the board to the meter.

static zap · Apr 9, 2019

Cheaper to tumble dry at night -
(If tumble-drier can be trusted)-De lint all innards! - Do check supplier has bill configured with 2 rates !

Simon0211 · Apr 9, 2019

ok thanks for this info - I'm def on 2 rates, I had heard that only items connected to the E7 board will give the cheaper rate at night - presumably not the case?

Richard Burns · Apr 9, 2019

The separate board easily allows the items powered during E7 times to be on only during those times. The whole board is switched (probably in your case by the meter). If you have just one board then each piece of equipment for E7 would need to have its own timer.
Some arrangements do mean only the E7 items are charged at the E7 rate and the main board at normal rate but your description does not sound like that (it is fairly old school now).
You probably have something like the below diagram

[ElectriciansForums.net] Economy 7 - need confusion clearing up please!

Simon0211 · Apr 9, 2019

Thanks again, my setup below...I assume as was only re-wired recently then i'm not on an old school setup?

Deleted member 26818 · Apr 9, 2019

When E7 was first introduced, two meters were required.
Normal meter was black, off peak meter was white, and the two meters were set at different rates.
Both meters could technically supply power at any time of the day, but the white meter was connected to a time clock which would only allow the power through at the set times.

Later a single dual tariff meter was designed, which had two connection points as per the drawing posted by Richard Burns. This meter could be remotely controlled by the supplier to turn on or off the off peak supply.

The introduction of such meters allowed for new tariffs such as E10 to be introduced.
The E10 tariff allowed the supplier to offer an extra 3 hours off peak during the evening in addition to the standard E7 times of midnight to 7am.

I can’t recall the times the extra 3 hours would be supplied during the evening, but the intention was for the supplier to choose hour slots where there was cheaper electricity.
So you could have supply from 7 to 8, 9 to 10 and 11 to midnight, 7 to 10, 9 to midnight or whatever combination the supplier deemed would be cheapest that day.

Many suppliers now offer a cheaper tariff for all electricity consumed at night, but still offer to switch the the second supply on and off remotely, so storage heaters are not on continuously.
In other cases, a time clock is required to control when power is delivered to storage heaters.

Richard Burns · Apr 9, 2019

Your set up when simplified and removing the earths is similar to my diagram but laid out like this

a few more joints and connections to confuse matters, but still the same idea.

Simon0211 · Apr 9, 2019

Richard Burns said:
Your set up when simplified and removing the earths is similar to my diagram but laid out like this

View attachment 48736
a few more joints and connections to confuse matters, but still the same idea.

thanks for this Richard - does that mean its 'normal E7' - i.e cheap rate during my E7 hours irrespective of which board the sockets/switches etc run off?

Richard Burns · Apr 9, 2019

Yes, during non E7 hours the top left board should be off and all power consumed by the lower right board will be at normal day rate.
When E7 hours start the top left board will be powered up and anything connected to it will start (if switched on). The meter will then be recording the power consumed by both boards on E7 night rate.

Simon0211 · Apr 9, 2019

Richard Burns said:
Yes, during non E7 hours the top left board should be off and all power consumed by the lower right board will be at normal day rate.
When E7 hours start the top left board will be powered up and anything connected to it will start (if switched on). The meter will then be recording the power consumed by both boards on E7 night rate.

Thanks Richard, good to know. There’s also an immersion label on the E7 left board and right main board but my immersion only has one input through a timer switch....something for an electrician to look at I guess. I’ve read that most e7 immersion tanks have a lower e7 immersion and upper normal. Ours only has normal and as far as I can tell.
Thanks again for help.

liebfraumilch · Oct 13, 2021

May I ask where the "2 rate digital meter" is usually located?

Avo Mk8 · Oct 13, 2021

liebfraumilch said:
May I ask where the "2 rate digital meter" is usually located?

Otherwise known as "the electricity meter" - for a private house, in a box outside in or on the wall somewhere, or indoors by the consumer unit. For an apartment/ flat, generally in a cupboard in a corridor on the same floor, sometimes basement or a central location.

liebfraumilch · Oct 14, 2021

Avo Mk8 said:
Otherwise known as "the electricity meter" - for a private house, in a box outside in or on the wall somewhere, or indoors by the consumer unit. For an apartment/ flat, generally in a cupboard in a corridor on the same floor, sometimes basement or a central location.

Thanks for replying!

In fact its a little observation* that brings me to this thread. Let me start just from the setup we have.

Our flat is on 4th floor. There's a meter room on the G/f hosting all the meters for the flats in the building.

Our meter looks like this, with three different readings alternating:

Inside our flat there're two fuse boards. I assume one is for OFF peak and one is for ON peak, judging from the connected appliances:

* Observation - we have a Gledhill Torrent thermal store, with two immersions, one connected to a OFF peak socket and one to a ON peak socket. Interesting enough, the OFF peak immersion will turn itself ON during daytime. This can't be right?

When we phoned Bristol Energy the provider, we're told our meter isn't a "Smart Meter", and scheduled ours for a upgrade.

Will that make any difference to our bizarre observation?

snowhead · Oct 14, 2021

Where the meters are located, is there any other boxes seemingly connected to the meters if so can you take a photo and post here?
There may be a separate time switch which has lost the correct time and is switching on early or if the meter has a built in time switch that may be wrong.

And re, will a Smart meter make any difference, given the limited knowledge of E7 and Off Peak installations that the average "Smart Meter" installer appears to have, it's quite likely you'll end up with no E7 working or it working all the time or some other variation.

No offence intended to the few knowledgeable "Smart Meter" installers, who usually end up sorting out the mess left by others.

Economy 7 - need confusion clearing up please!

Simon0211

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littlespark

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static zap

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Simon0211

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Richard Burns

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Simon0211

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Deleted member 26818

Richard Burns

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Simon0211

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Richard Burns

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Simon0211

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liebfraumilch

Avo Mk8

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liebfraumilch

snowhead

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