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Chat Area => General Discussion Area => Topic started by: zirk on 13 January 2014, 10:53:29

Title: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 10:53:29
Im referring to Economy 7 Meter and wiring, which is installed here about 25 years ago,and which we dont use, or least the Storage Heaters anyway.

Question is this, when the Cheap rate kicks in, you can hear the a loud relay clicking in near the Meter, I assume this then feeds the pre installed wiring that feed each Heater, guesing there 16 A spurs to each one?

So does the cheap rate supply only apply to the heating wiring, or the whole normal House wiring?, ie if I put a Timer on the Dish Washer and Washing Machine plugged into the normal 13A Ring supply, to kick in at say 2am, will this use the Cheap Rate Supply Tarriff or would they need to wired to the Heating Supply?

I asked the question to a number of people now including my Lic'y Supplier with mixed answers!, anyone know for sure?

Cheers Chris.  :y
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 11:08:40
How many consumer units have you got Chris ?
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 11:13:53
I'll go and have a look.  ;)
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Marks DTM Calib on 13 January 2014, 11:26:15
You often see two consumer units for the older E7 installs with storage heaters, the contactor switches the supply on/off to the second consumer unit.

As for the question re-dishwasher etc, yes, simply fitting a timer to operate the devices during E7 times will result in billing at E7 rates if you have the the modern meters with dual tarif on the them
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 11:35:50
Right had a quick look, loads of wires going everywhere so bare with me, and its a 70's build house.

Looks like a Have SWA in that feeds a Master Fuse and Connection Block, 3 wire out of that, 2 Thick, 1 Thin, the 2 Thick go to the LCD Meter (Meter replaced by E- on about 10 years ago), The 1 Thin wire goes via a Fuse to a stand alone Big Black Box (Guessing this might be the Relay).

From the Meter various Thick wires to the Main Fuse Board, 1 thick wire goes to the Black Box (Relay?) and then back out again to feed a separate White Fuse Box which looks like it feeds the Heating Spurs.

Also checked the Main Meter and it gives me Peak and Off Peek readings.

Hope that helps.  ;)
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 11:43:02
Right, your white box sounds like its a dedicated unit for the eco 7.

Might be a bit naughty  :-X but how far away is the washing machine from the nearest storage heater ?
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 11:48:14
Right, your white box sounds like its a dedicated unit for the eco 7.

Might be a bit naughty  :-X but how far away is the washing machine from the nearest storage heater ?

Theres a Heater in the Kitchen not near the Dish / Washers but do-able for re route.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Kevin Wood on 13 January 2014, 11:49:48
Yep, the meter is programmed to switch tariff and, when it does so, it energises the relay via the "thin" wire, causing the storage heaters to start charging via the white consumer unit.

The meter will record all consumption at the economy 7 tariff during this period, so it's enough just to set a timeswitch for any other appliances.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 11:56:27
Right, your white box sounds like its a dedicated unit for the eco 7.

Might be a bit naughty  :-X but how far away is the washing machine from the nearest storage heater ?

Theres a Heater in the Kitchen not near the Dish / Washers but do-able for re route.


Right bud, IF IT WAS ME, and the dishwasher cable can be re route to reach the spur, remove the plug of the dishwasher wire and connect it into the fused spur for the storage heater after removing the heater wires  ;)
Make sure you have a 13 amp fuse fitted to the spur.
Taking that all the fuses in the white unit are removed, replace the one for the kitchen and your sorted.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 11:58:18
Or .............. you can contact your service provider and get them to remove the heater side and connect the full house up (which will cost you a shed full of money)  ;)
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Marks DTM Calib on 13 January 2014, 12:12:15
Or just buy a cheap timer for a tenner.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 12:29:58
Iirc, if you replace the spur with a socket and plug a mechanical timer into it, it constitutes a change of use which (and I haven't checked yet) comes under Part P  :(

Chris, is your dishwasher the old mechanical type ?
Or if its electronic, does it have a timer (power on) facility on it ?
In other words, can it be set up so that when power is applied it kicks straight into wash cycle ?
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 12:30:39
Ok, thats all, so to confirm the existing wiring from the Normal CU will give me Off Peak rates, or am I looking at re routing each E7 Spur to fit the bill?

In that case Im kind of thinking the whole idea off having a second E7 CU feeding each Heater via a relay is so the Heaters cant be accidentally switched on during the day time and gobble up the Lic Bill on Peak Rate?, correct?.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: tigers_gonads on 13 January 2014, 12:36:14
 ;D ;D ;D

To get your houses consumer unit to give you eco 7, you have to modify the incoming mains to that consumer unit.

If you are only talking about the dishwasher then i'd reroute the cable as per the other post  :)
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Marks DTM Calib on 13 January 2014, 12:59:32
No you dont.

The meter will record E7 consumption of either boards.

So a simple plug in timer will do the job.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Marks DTM Calib on 13 January 2014, 13:04:07
In that case Im kind of thinking the whole idea off having a second E7 CU feeding each Heater via a relay is so the Heaters cant be accidentally switched on during the day time and gobble up the Lic Bill on Peak Rate?, correct?.

Yes and so that you only need a single contactor to turn the storage heaters on.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 14:01:28
In that case Im kind of thinking the whole idea off having a second E7 CU feeding each Heater via a relay is so the Heaters cant be accidentally switched on during the day time and gobble up the Lic Bill on Peak Rate?, correct?.

Yes and so that you only need a single contactor to turn the storage heaters on.

Thanks all, Ive got some 13A Timers kicking around somewhere so I'll have a play.

Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: MR MISTER on 13 January 2014, 15:19:36
In that case Im kind of thinking the whole idea off having a second E7 CU feeding each Heater via a relay is so the Heaters cant be accidentally switched on during the day time and gobble up the Lic Bill on Peak Rate?, correct?.

Yes and so that you only need a single contactor to turn the storage heaters on.

Thanks all, Ive got some 13A Timers kicking around somewhere so I'll have a play.
I thought of doing this when I was on E7 but...my washing machine and drier both need a physical button press to start them off...and the noise would do my head in.
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 13 January 2014, 15:27:04
In that case Im kind of thinking the whole idea off having a second E7 CU feeding each Heater via a relay is so the Heaters cant be accidentally switched on during the day time and gobble up the Lic Bill on Peak Rate?, correct?.

Yes and so that you only need a single contactor to turn the storage heaters on.

Thanks all, Ive got some 13A Timers kicking around somewhere so I'll have a play.
I thought of doing this when I was on E7 but...my washing machine and drier both need a physical button press to start them off...and the noise would do my head in.
Hoping the noise will drown out the shootings and sirens.  ;D
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: Taxi_Driver on 15 January 2014, 06:59:27
If your not using the storage heaters.....surely it must be cheaper to get the leccy company to rip the E7 out and fit a 'normal' meter.....you will be paying well over the 'normal' tariff during the day as it is...
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 17 January 2014, 15:33:57
If your not using the storage heaters.....surely it must be cheaper to get the leccy company to rip the E7 out and fit a 'normal' meter.....you will be paying well over the 'normal' tariff during the day as it is...
Last time I checked, couple of months ago, we were paying something like 14.5p during peak rates, which from memory was around 1.5p more over a standard tarriff, off peak on E7 is about 5p per unit, so a big difference, we are currently using a third off peak but intend to increase that.

Plus Ive also got a 10 Kva UPS and a massive external Battery pack I intend to start playing with off peak, despite the in-efficiency of the inverter, could still be some savings to had.  ;)
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: MR MISTER on 17 January 2014, 16:11:58
If your not using the storage heaters.....surely it must be cheaper to get the leccy company to rip the E7 out and fit a 'normal' meter.....you will be paying well over the 'normal' tariff during the day as it is...
Last time I checked, couple of months ago, we were paying something like 14.5p during peak rates, which from memory was around 1.5p more over a standard tarriff, off peak on E7 is about 5p per unit, so a big difference, we are currently using a third off peak but intend to increase that.

Plus Ive also got a 10 Kva UPS and a massive external Battery pack I intend to start playing with off peak, despite the in-efficiency of the inverter, could still be some savings to had.  ;)
According to EON, I needed to use 37% of my electricity on E7 to make it worthwhile. I was using about 10% so switched to 24 hour normal tariff. But then again, it's my gas bill that is the big one (gas CH).
Title: Re: Sparks or Heating Engineers Question - Economy 7 Wiring?
Post by: zirk on 17 January 2014, 17:59:17
According to EON, I needed to use 37% of my electricity on E7 to make it worthwhile. I was using about 10% so switched to 24 hour normal tariff. But then again, it's my gas bill that is the big one (gas CH).
Fairly sure mine was about 27%, not keen on changing my tarriff tbh, as its only about £38 a month and has been for years.