Economy 7 hours

atalosstoo

Utility Warehouse tell me that Economy 7 is usually 12 to 7 but that not all metres switch at the same time because there would be an energy surge. So they say that it could switch anywhere up to two hours after 12 at night and the only way to know is by waiting to hear it click. Surely this cannot be true?

Verdigris

What is true is that there is an up to two hour tolerance on the timing of off peak. It dates back to the days of electro-mechanical timers which can't account for GMT/BST and are just not totally accurate. If you have a modern electronic dual-rate meter, that will keep its own time, only the one hour variation for BST/GMT will occur. If you have a radio controlled switch (teleswitch), or a smart meter, the times will be accurate and GMT/BST will be taken into account.

MWT

The times do vary by region as well...

Verdigris

That's interesting. Every day's a school-day!

Gerry1

Verdigris said: If you have a radio controlled switch (teleswitch), or a smart meter, the times will be accurate and GMT/BST will be taken into account.

If you have a radio teleswitch the times can vary by +/- 15 minutes.   That's intentional, the variance is to manage the demand.  It's also likely that the switch will ignore GMT/BST, e.g. it will start at 10:30pm in the winter and 11:30pm in the summer.  Again, that's intentional so that local timers (for immersion heaters) don't have to be changed.

If your devices are on a switched circuit you don't have to worry but if you have a local timer or set the washing machine / tumble dryer etc to a delayed start then you need to be aware.

QrizB

I live in region 20 - Southern - and when I had an all-electric house the times were pretty much as shown on the map. There was a neon indicator on the immersion heater which made it easy to check whether the E7 period had started before setting the washing machine off for the the night.

Haarlem

Gerry1 said:

Verdigris said: If you have a radio controlled switch (teleswitch), or a smart meter, the times will be accurate and GMT/BST will be taken into account.

If you have a radio teleswitch the times can vary by +/- 15 minutes.   That's intentional, the variance is to manage the demand.  It's also likely that the switch will ignore GMT/BST, e.g. it will start at 10:30pm in the winter and 11:30pm in the summer.  Again, that's intentional so that local timers (for immersion heaters) don't have to be changed.

If your devices are on a switched circuit you don't have to worry but if you have a local timer or set the washing machine / tumble dryer etc to a delayed start then you need to be aware.

I live in the East Midlands area with a teleswitch.  Had it for over 30 years.  The lower rate is 01.00 to 08,00 all the year round.  
I worked in the industry and tleswitches were marketed on the selling point that they took account of GMT/BST so customers could take advantage of constant times all the year round. 
We in the East Midlands are lucky that 08.00 is a reasonable time most people can take advantage when they first get up.  I don't have electric heating, but my consumption averages 35% at the lower rate.

Gerry1

Haarlem said:

Gerry1 said:

Verdigris said: If you have a radio controlled switch (teleswitch), or a smart meter, the times will be accurate and GMT/BST will be taken into account.

If you have a radio teleswitch the times can vary by +/- 15 minutes.   That's intentional, the variance is to manage the demand.  It's also likely that the switch will ignore GMT/BST, e.g. it will start at 10:30pm in the winter and 11:30pm in the summer.  Again, that's intentional so that local timers (for immersion heaters) don't have to be changed.

If your devices are on a switched circuit you don't have to worry but if you have a local timer or set the washing machine / tumble dryer etc to a delayed start then you need to be aware.

I live in the East Midlands area with a teleswitch.  Had it for over 30 years.  The lower rate is 01.00 to 08,00 all the year round.  
I worked in the industry and tleswitches were marketed on the selling point that they took account of GMT/BST so customers could take advantage of constant times all the year round. 
We in the East Midlands are lucky that 08.00 is a reasonable time most people can take advantage when they first get up.  I don't have electric heating, but my consumption averages 35% at the lower rate.

Seems that it can be configured either way.  I've had mine for a similar time.  Originally it was seven consecutive hours, but I soon discovered that it could have a two hour gap, so I had it changed.  Now the split times seem to be standard for Region 19, the South East area.  My teleswitch stays on GMT.

coffeehound

My last E7 place had radio-controlled switching and didn't take account of DST changes.  As with all things E7, take nothing for granted!  

There's a gap in the market for a device that monitors the off-peak indicator light and signals remote plug-in and hard-wired switches for immersion heaters, NSHs, etc.  When you have to set timers to allow for the 15 minute variance at each end of the off-peak period, you lose half an hour of precious cheap-rate

Gerry1

coffeehound said:

My last E7 place had radio-controlled switching and didn't take account of DST changes.  As with all things E7, take nothing for granted!  

There's a gap in the market for a device that monitors the off-peak indicator light and signals remote plug-in and hard-wired switches for immersion heaters, NSHs, etc.  When you have to set timers to allow for the 15 minute variance at each end of the off-peak period, you lose half an hour of precious cheap-rate

Or an hour if there's a two hour interlude at peak rate...

Far better to have a 5-terminal meter.  Not all meters / teleswitches have an off peak indicator light; my teleswitch just has a red lever, and the meter just has an unilluminated LCD.

coffeehound

Gerry1 said:

Far better to have a 5-terminal meter.  Not all meters / teleswitches have an off peak indicator light; my teleswitch just has a red lever, and the meter just has an unilluminated LCD.

Good point.  I think some/most/all multi-rate smart meters have a 'pilot' terminal that can be used to energise an external contactor even if they aren't 5-terminal with a second internal contactor.  So that pilot terminal could presumably also be used to control a remote wifi transmitter i suppose.