Economy 7 :: What's what?

[DaveyD]

Hi everyone

My friend has this E7 set up and TBH I don't know how it works switching wise.

It has two 17th ed. CU's recently installed. One for daytime and one for night time. I thought E7 has one CU and just switches over everything, so what's going on here please with the two CU's.

Here is the meter box



The E7 CU has the night storage heaters and water heater on. My mate has bought a new 2.77kw water heater and to "save money" bought a single rather than a Twin immersion Heater



So he has the plumber wire it to the day rate switch (top switch). Now he wants me to wire to E7 switch (bottom).


Sorry in advance if this question is too simplistic for you and thank you.

Kindest Regards, David

 

[adslev]

I know that any installs i have worked on with E7 have had one board for general power, lights, sockets and the other board only for the storage heaters, like you said they work of a lower tariff, tbh the storage heaters should have stored sufficient heat if they are operating correctly at night and I would leave them on their own dedicated CU, IMO of course!!

 

[robsparky1975]

Not sure on what it is you need to know,1 consumer unit is unrestricted(peak supply).other unit is economy 7(restricted between 23.30-0630),the electric meter had certain readings a b etc, rate 1(say 10p kwh),rate 2 say 5p kwh,in your picture the black unit is a switch which powers up the restricted supply for the rate 2,any other power taken at nightime from the unrestricted supply will be priced at the rate 2 as this is done automatically in the meter.whats wrong with the immersions?

 

[DaveyD]

Thanks for your reply guys.

Not sure on what it is you need to know,1 consumer unit is unrestricted(peak supply).other unit is economy 7(restricted between 23.30-0630),the electric meter had certain readings a b etc, rate 1(say 10p kwh),rate 2 say 5p kwh,in your picture the black unit is a switch which powers up the restricted supply for the rate 2,

Switch, ok thanks.

any other power taken at nightime from the unrestricted supply will be priced at the rate 2 as this is done automatically in the meter.whats wrong with the immersions?

If I rewire to the e7 then he wont have any hot water in the daytime. Is the main C/U NOT E7 at night too?

 

[robsparky1975]

how many immersions now just 1

 

[DaveyD]

how many immersions now just 1

Yes just one Rob

 

[terminator]

Just leave it on the day rate switch and add a timer - that way he can swich it manually as well. If you put it on night rate, he has no use or option during the day.

 

[robsparky1975]

if only 1 immersion he needs an economy 7 water heater controller,something like a horstmann,both the peak and off peak supplies from ccus are wired into these,with 1 heat resistant flex(2.5mm)going to a single immersion heater,this gives the off peak as normal at night time and has a dial on the front of unit which can allow a 2 hour daytime boost via the peak supply.dont take this the wrong way(im not sure what your level of experience is),this needs to be done by a competant electrician,if your competant then carry on and disregard me asking,its just to be on the safe side im sure you understand.

 

[DaveyD]

So are you saying that as I suspected the main C/U will run the whole house at E7 overnight. The black switch in the meter box is just to turn the storage heaters on and off (plus the now redundant water heater feed)?

 

[DaveyD]

if only 1 immersion he needs an economy 7 water heater controller,something like a horstmann,both the peak and off peak supplies from ccus are wired into these,with 1 heat resistant flex(2.5mm)going to a single immersion heater,this gives the off peak as normal at night time and has a dial on the front of unit which can allow a 2 hour daytime boost via the peak supply.dont take this the wrong way(im not sure what your level of experience is),this needs to be done by a competant electrician,if your competant then carry on and disregard me asking,its just to be on the safe side im sure you understand.

Thank you , no offense - I understand where you are coming from. Yes I am competent and qualified I have just never done E7 before. So not as experienced as many here with that.
Kind Regards, David.

 

[pushrod]

Slightly off topic, but you need to be really careful with a lot of E7 deals as they are a con and only actually give you a saving if you are using absolutely masses at the cheap rate as they often charge more for the ordinary rate than you can get with other deals. Unfortunately i know from experience. When i went through the charges carefully i discovered that using the dishwasher and washing machine on timers to come on with the E7 was actually costing me money

 

[DaveyD]

i discovered that using the dishwasher and washing machine on timers to come on with the E7 was actually costing me money

! I don't have it here - but how was that? Regards, David

 

[robsparky1975]

So are you saying that as I suspected the main C/U will run the whole house at E7 overnight. The black switch in the meter box is just to turn the storage heaters on and off (plus the now redundant water heater feed)?

yes the switch clicks on at 23.30,the unresticted supply gets reduced rate prices overnight,this is why a few people do there laundry after midnight.remember that you will need the off peak water heater feed to go through your water heater timer.you need peak and off peak.look up the horstmann range they have diagrams and everything,also,have a google for economy 7 and a good read up with pics should help out a bit more.

regards rob

 

[robsparky1975]

Slightly off topic, but you need to be really careful with a lot of E7 deals as they are a con and only actually give you a saving if you are using absolutely masses at the cheap rate as they often charge more for the ordinary rate than you can get with other deals. Unfortunately i know from experience. When i went through the charges carefully i discovered that using the dishwasher and washing machine on timers to come on with the E7 was actually costing me money

good point,although it says ECONOMY,check carefully on what the kwh prices per unit are,these suppiers can be sneaky.

 

[pushrod]

! I don't have it here - but how was that? Regards, David

because although the E7 rate was cheap the standard rate was actually more expensive than other rates that were available. We moved into our house and just assumed for a couple of years that it was sensible to have and was saving us money ... WRONG!
Got rid of it when we finally checked it out.