Storage heaters

uksparks · Aug 6, 2014

Hi,

Ok so the new meter has been installed and the customer now wants 4 storage heaters, you can see the meter below.

Whats the best way to go about it as theres only one output.

He needs a new consumer unit anyway, do I just put it all in one CU or split it and have it in two CU's

But the timer issue, shall I use a contactor and a time clock inside a separate CU to feed the heaters?

[ElectriciansForums.net] Storage heaters

Richard Burns · Aug 6, 2014

Replace the 2nd RCD with a contactor feeding the S/Hs, supply a timer from the 24hr side and use RCBOs for the S/Hs (if required).

I really have not thought this through, just an idea.

7029 dave · Aug 6, 2014

uksparks said:
Yeah thats what im thinking then just split the neutral and jobs a good'n

Yep UK easy.

Carlosfandango · Aug 6, 2014

But then surely all the domestic circuits will be on one rcd? Easier to fit 2 db's. Every e7 meter I've fitted has a 5th terminal, are you sure it's not an economy 10 meter?

7029 dave · Aug 6, 2014

They do E10 5th terminal to.

davesparks · Aug 6, 2014

dingledong said:
That's not a dual tariff meter ? Why is it sealed as an extra wire has to come out of it ! !
Now it's sealed you can't do that

That is a multi rate meter, this can be easily distinguished by reading what is written on it!

Why does an extra wire have to come out of it? Dual rate meters switch between two different charging rates with the whole of the power consumption being billed at each rate.
I think you are getting this confused with the ones which energise a second supply for off-peak.

uksparks · Aug 6, 2014

Dave , ideally if like a second energised supply on a. 5th terminal.

uksparks · Aug 6, 2014

Richard Burns said:
Replace the 2nd RCD with a contactor feeding the S/Hs, supply a timer from the 24hr side and use RCBOs for the S/Hs (if required).
View attachment 25790
I really have not thought this through, just an idea.

Thats really good thanks, it's given me something to think about, maybe if I can get three RCDs in the board it will work.

how did you draw this by the way?

dingledong · Aug 6, 2014

You need a trigger wire that comes from the fuse board

dingledong · Aug 6, 2014

Lost here I thought he wanted off peak ! ? ! ?

Richard Burns · Aug 6, 2014

uksparks said:
Thats really good thanks, it's given me something to think about, maybe if I can get three RCDs in the board it will work.

how did you draw this by the way?

I just do diagrams in power point I am afraid, not big, not clever, but simple enough for me!

davesparks · Aug 6, 2014

uksparks said:
Dave , ideally if like a second energised supply on a. 5th terminal.

Would you fit a seperate 3 pole main switch to achieve a single point of isolation for the installation?

It's a question which I have pondered over in the past, but never had to deal with.

You say you would like a 5th terminal which would give you a second live which is off-peak switched in the meter, but is this what the customer wants? Or do they want the whole installation being on dual rate so that they can run other things on the off peak?
Also going back to the immersion heater you will then be wanting to run a second off peak supply for it plus they'll realistically need a dual element cylinder.

There's no point having an E7 or off peak supply and not making the most use of it!

7029 dave · Aug 6, 2014

What do you mean Dave.? The general domestic board goes over as well.

Richard Burns · Aug 6, 2014

dingledong said:
Lost here I thought he wanted off peak ! ? ! ?

The meter that has been installed simply changes the rate at the appropriate time for the whole supply to the property.
This is good for the consumer because all the power usage off peak is cheap, it is bad for the electrician because he has to set up the timing for off peak, and this is not fixed in many cases.

stevethesparks · Aug 6, 2014

Henley block supplying a separate CU via a contactor controlled by a time clock fed from the existing CU
As Davesparks says, its a dual rate meter

davesparks · Aug 6, 2014

dingledong said:
You need a trigger wire that comes from the fuse board

Trigger for what??

The meter has a built in equivalent of a teleswitch which swaps it from peak rate to off peak rate as appropriate.
The older version of this had a seperate teleswitch which had a pilot wire which switched the meter from peak to off peak rates
The even older version used a timeswitch to switch the rates on the meter.

This is not the same as the system where a second supply is energised and metered seperately during the off peak hours.

One system is E7 the other is true off-peak but I don't know which way round it is.