new supply with economy 7

[1john]

I have got a new build to price for, something I haven't had to opportunity to do in a while, the property is to have economy 7 heating, something I have never done on a new build. In all the rewires I have ever done the economy 7 has a separate meter and two sets of tails are ran two the corresponding distribution boards.

My question is, are new supplies configured in the same way as I have experienced or will there be a 'dual tarriff meter' (something in which I have never worked with before)? Perhaps I would be better off contacting the DNO?

Depending on responses to this I would like to pick brains on peoples methods of running SWA's from an external meter cabinet to a distribution board located some distance from said cabinet.

Regards

John

 

[Stoday]

"Economy 7" uses a single meter that can total day and night useage separately.

The double meter arrangement is no longer available for new supplies and was originally for off peak supplies, i.e. the night meter measured off peak useage, the other meter both day and night useage.

 

[1john]

I see, so each storage heater will require a timer set to 'off peak' times?

I think I prefered the old method, the storage heaters were only on when off peak was available, I guess now they can potentially be over-ridden at any time.

 

[ajrobb]

You can get a radio teleswitch that switches the heating AND allows the supplier to smooth demand and offer more competitive rates. So, very similar to the old switching meter in that you need a separate CU for heating.

 

[Lectrician]

Just present two sets of tails to the metering position - Your jobs done.

The meter operator will then fit what they want to fit, be it an all in one dual rate with combined teleswitch, a seperate dual rate with external teleswitch, a timer instead of the teleswitch (jest - not since the 70's!).

Consider peak and off pear supplies (use a dual back box) for heaters in principle rooms to allow combi storage heaters to be fitted rather than standard.

Common to storage heating downstairs and panel heaters in the bedrooms.

A peak and off peak supply to the airing cupboard for the immersion heaters - two elements in the tank, peak to the top element and off peak to the bottom. Common to fit a 3 stage timer to the peak element, or a DP switch with neon. Most people will fit a DP switch without a neon for the off peak element.

 

[1john]

Lectrician, thanks for your reply, firstly, how do the dno normally feel about being presented with SWA at the cabinet? The run for tails will be in excess of 3m and take a 10m run looking at the drawing by eye.

For immersion heaters I have always used a 20/32A rotary change over switch to enable people to boost the heat to the water.

 

[OwainDIYer]

For immersion heaters I have always used a 20/32A rotary change over switch to enable people to boost the heat to the water.

If you supply the immersion(s) from the peak CU then the immersions can be controlled by an economy 7 immersion timer

These allow a timed boost and can be wired for one or two heaters, with the boost to the top and the off-peak to the bottom, interlinked so only one heater operates at a time and you only need one circuit from the CU.

 

[Wontdothatagain]

There are 2 types of meters available, a 4 port and a 5 port. If you have a 4 port, the entire house will switch to the off peak rate at the specified time, if you have a 5 port, it will live up the extra port at the relervent time and the meter will change over to the off peak read at the relervent time.

If you are going to be running SWA with a 5 port meter, i would do it like this,

Meter tails into a 4 port isolator, Wylex REC4, supply company may fit one or you may have to, they will seal the top of the isolator either way and leave the bottom unsealed for you to attach your tails.

Peak Line tail to the consumer unit, neutral to a 100A Henley Block and from 1 port of the Henley to the Peak consumer unit.

Off peak Line tail from the isolator and second Neutral from the henley block to a suitable metal enclosure with correct sized connectors inside, connect the SWA for off peak consumer unit here. Ensure Earthing/Bonding arrangements are met to the metal enclosure.

If you have a 4 port meter, use a 2 pole isolator, Wylex REC2, run the tails from the isolator to 2 Henley blocks and split them from there.

You could also fit a second 2 pole isolator before the metal box to isolate the off peak SWA

1 other point, how many heaters are going to be on the off peak board???? If it is a lot you may need to spec a second phase to the property and this would be done with a 3 phase meter and the 3rd phase blanked off.