Basic economy 7 question

[m4tty]

Hi,

Not come across more than 2 e7 installs and they both were separate boards for e7 and normal.

I came across one today which I will be doing a load of work round soon which I think had one bs3036 fuseboard which I will be changing soon which was fed by both meters?

Is this normal for the whole house to get e7 cheaper rate?

Any info on e7/10 would be much appreciated

Thanks in advance

Matty

 

[Andy™]

how exactly was it wired? both lives into same terminal of CU?

 

[jameseye12]

I've come across economy seven installs that have separate boards but both boards are fed from the same live and so are both switched to E7 and I've also come across installs with a single board and the whole supply is switched to E7

 

[revjames]

usually the 2 rate meter switches (via clock or teleswitch) between low and normal tariffs. So yes whole house on E7 midnight to 7am - usually a 16mm cable coming out of teleswitch ot timer into the E7 heating board. I used to put in MG boards for whole house installation with internal contactor for the heaters and hot water. Contactor switched from teleswitch.

HTH

James

 

[m4tty]

[quote name='Andy

 

[ProDave]

I've seen old Wylex boards where there are two rows of fuses in the one metal clad housing.

The top one is the normal circuits, and the bottom one is the off peak circuits.

They are completely separate apart from sharing a common earth terminal bar.

I've even seen a version where the bottom row is split into two, so that the single circuit feeding the water heater can have it's own switch.

Another variant on Off peak is "total control" Now that WAS an interesting tarrif. You will usually find 3 CU's:

Main circuits get peak rate in the day and cheap rate at night.

Off peak circuits (storage heaters etc) get cheap rate at night.

But the best bit is "total control" circuits get the cheap rate 24/7.

You are only supposed to connect heating circuits to the "total control" CU such as panel heaters, and it seems common to connect a shower there. Why you would ever want to bother with storage heaters, when you can have much more controlable panel heaters at the cheap rate on at any time beats me.

That is a "preserved tarrif" so no longer available to new customers. So if ever you come across one of those, strongly advise the customer to keep it.

As most total control systems were a retro fit, it's common to find the main CU is still an old wylex rewirable, but the total control and off peak CU's are nice modern one's with MCB's. Always seems kind of ironic that the most important circuits have the least protection.

 

[batty]

Didn't pay much attention to it as I was there for something different and thought of it on way home ffs. But think both tails must go in top of mainswitch ? Is that a normal setup? Cheers

If it did there storage heaters would be on 24 hrs a day something not quite right there I think.

 

[th3pony]

a customer has asked me to convert current economy 7 into 13amp sockets, having not really dealt with economy 7 i dont really know much about it, has anyone got any knowledge for me.

 

[ProDave]

a customer has asked me to convert current economy 7 into 13amp sockets, having not really dealt with economy 7 i dont really know much about it, has anyone got any knowledge for me.

Assuming they are having the storage heaters removed, then you can indeed utilise the existing wiring to provide extra sockets if it's no longer needed for storage heaters.

Are they still keeping the E7 tariff? not so daft as it sounds as it can still be worthwhile if you use the washing machine or dishwasher at night on the cheap rate.

If they are, then you will have to move the existing cables that used to feed the storage heaters over to the main CU and connect them as radial circuits on a suitable MCB.

If they are not keeping the E7 at all, then the old E7 CU will become redundant. It is sometimes possible just to power that up as a second, permanently fed CU to feed your radial sockets.

BUT in doing all of this you will almost certainly need RCD protection, something the old E7 CU may not (probably won't) give you so you need to work with what you have and make suitable alterations, e.g replace old E7 CU isolator switch with an RCD.