UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old February 6th 19, 01:58 PM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)



--

Roger Hayter

  #2   Report Post  
Old February 6th 19, 06:57 PM posted to uk.d-i-y
ARW ARW is offline
external usenet poster
 
First recorded activity by DIYBanter: Aug 2012
Posts: 8,004
Default Economy 7 supply wiring question

On 06/02/2019 12:58, Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)




With the main fuse out everything should be dead.

--
Adam
  #3   Report Post  
Old February 6th 19, 07:46 PM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Aug 2006
Posts: 9,657
Default Economy 7 supply wiring question

When they were working on mine they switched the house supply off.
ahem. Careful prudent, safe?
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Roger Hayter" wrote in message
...
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)



--

Roger Hayter



  #4   Report Post  
Old February 7th 19, 02:04 AM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

ARW wrote:

On 06/02/2019 12:58, Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)




With the main fuse out everything should be dead.


True, but I only want to change an MCB for an RCBO in the economy 7 CU
and would prefer to rely on the main switch if it isafe to do so.
Removing the main fuse is potentially hazardous, isn't it?

--

Roger Hayter
  #5   Report Post  
Old February 7th 19, 02:04 AM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

Brian Gaff wrote:

When they were working on mine they switched the house supply off.
ahem. Careful prudent, safe?
Brian

Where was the switch they used? Or did they take out the main fuse?

--

Roger Hayter


  #6   Report Post  
Old February 7th 19, 02:30 PM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

Roger Hayter wrote:

ARW wrote:

On 06/02/2019 12:58, Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)




With the main fuse out everything should be dead.


True, but I only want to change an MCB for an RCBO in the economy 7 CU
and would prefer to rely on the main switch if it isafe to do so.
Removing the main fuse is potentially hazardous, isn't it?


In response to a very sensible email suggestion, here are some photos.
As an added bonus, does anyone think a Wylex RCBO will fit in the one
unit CU photoed?

Thanks all for advice.

http://www.photobox.co.uk/album/5568689698

--

Roger Hayter
  #7   Report Post  
Old February 7th 19, 07:16 PM posted to uk.d-i-y
ARW ARW is offline
external usenet poster
 
First recorded activity by DIYBanter: Aug 2012
Posts: 8,004
Default Economy 7 supply wiring question

On 07/02/2019 13:30, Roger Hayter wrote:
Roger Hayter wrote:

ARW wrote:

On 06/02/2019 12:58, Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)




With the main fuse out everything should be dead.


True, but I only want to change an MCB for an RCBO in the economy 7 CU
and would prefer to rely on the main switch if it isafe to do so.
Removing the main fuse is potentially hazardous, isn't it?


In response to a very sensible email suggestion, here are some photos.
As an added bonus, does anyone think a Wylex RCBO will fit in the one
unit CU photoed?

Thanks all for advice.

http://www.photobox.co.uk/album/5568689698


You cannot fit a RCBO into that CU. That looks like an old plug in fuse
that has been swapped for a MCB.

Thanks for the pictures.

--
Adam
  #8   Report Post  
Old February 7th 19, 09:42 PM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Mar 2008
Posts: 108
Default Economy 7 supply wiring question

Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.

However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.


OK, so it sounds to me like the 25mm wires carry the power. The 10mm
ones power the timeswitch, and the 6mm one signals the meter to change
rate. If you can find a model number of the timeswitch you may be able
to Google somthing that will confirm it.

The supply that powers the timeswitch should be isolated from the
switched terminals. If power flowed between them it would be dangerous
for a number of reasons - as you say, the switch would not reliably cut
power, but also with the switch open the electric heaters would run
through a 10mm tail protected only by a 100A fuse. So I think you can be
fairly confident that the switch does in fact cut all output power -
only the timeswitch and meter stay live.

The consumer units should also have shrouds on the incoming terminals,
so as long as the main switch in the CU is also off the CU won't become
live even if power was supplied unexpectedly. If I was working on the
input side of the CU, I'd be tempted to remove the main fuse anyway
(though strictly this is illegal).

It's something to be careful of in multi-rate installations that there's
often not a single switch to cut all power to the building. My house
used to have THTC, which meant there were *four* main switches
(general supply, 24 hour heating, water heating, timed heating). Unless
all four were off, something was still powered or could become powered
under timeswitch control.

Mike
  #9   Report Post  
Old February 8th 19, 12:27 AM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

ARW wrote:

On 07/02/2019 13:30, Roger Hayter wrote:
Roger Hayter wrote:

ARW wrote:

On 06/02/2019 12:58, Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.


However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.

Can I assume that none of the Henley blocks is live when the main fuse
is open? In theory any one of the last three wires by-passes the main
switch and could internally connect the night time supply to the live
via the radio switch box. And theoretically could back feed the main
house CUs via the live in connection to the radio switch. Is it safe
to assume with a high degree of reliablity that the internal
construction of the radio switch is such as to make this impossible?

(Obviously I wouldn't work on anything without checking it is not live,
but the radio switch is, after all, a switch and if it could connect
live to the wrong wiring could presumably do it suddenly and
unexpectedly.)




With the main fuse out everything should be dead.

True, but I only want to change an MCB for an RCBO in the economy 7 CU
and would prefer to rely on the main switch if it isafe to do so.
Removing the main fuse is potentially hazardous, isn't it?


In response to a very sensible email suggestion, here are some photos.
As an added bonus, does anyone think a Wylex RCBO will fit in the one
unit CU photoed?

Thanks all for advice.

http://www.photobox.co.uk/album/5568689698


You cannot fit a RCBO into that CU. That looks like an old plug in fuse
that has been swapped for a MCB.

Thanks for the pictures.


OK so its a new CU or delete the economy 7 cirtuit. Thanks, that's
useful to know. It is mainly borderline OCD that makes me want to
change it just because it is the only circuit in the house not protected
by an RCD.

PS I suppose I can't use an RCBO on its own without a mains switch a) to
make servicing the RCBO safer and b) because I won't find an RCBO with
16mm terminals. Is there a more fundamental reason?

(I realise me doing it is all theoretical because of part P, of course,
but I can influence the specs! Another practical electrician question
is whether someone who replaced this CU would have to test the whole
house installation?)

I've carefully avoided checking that the economy 7 circuit is wired as a
ring so far, but I suppose I could always use a smaller MCB.


--

Roger Hayter


  #10   Report Post  
Old February 8th 19, 12:27 AM posted to uk.d-i-y
external usenet poster
 
First recorded activity by DIYBanter: Apr 2013
Posts: 1,995
Default Economy 7 supply wiring question

Mike Humphrey wrote:

Roger Hayter wrote:
I have an economy seven supply. Two 25mm wires go from the main fuse
block to the meter (presumably live and neutral) and then to a switch
and then to two Henley blocks. From one of these a 25mm wire goes to a
radio controlled switch, and out of this time switch another 25mm wire
goes to a third Henley block. The house supply runs from the first two
blocks, and a separate wire from the third block presumably supplies
live to the night time only supply.

However, there are two 10mm wires from the main fuse block to the radio
switch, and one 6mm wire joins the radio switch to the meter.


OK, so it sounds to me like the 25mm wires carry the power. The 10mm
ones power the timeswitch, and the 6mm one signals the meter to change
rate. If you can find a model number of the timeswitch you may be able
to Google somthing that will confirm it.

The supply that powers the timeswitch should be isolated from the
switched terminals. If power flowed between them it would be dangerous
for a number of reasons - as you say, the switch would not reliably cut
power, but also with the switch open the electric heaters would run
through a 10mm tail protected only by a 100A fuse. So I think you can be
fairly confident that the switch does in fact cut all output power -
only the timeswitch and meter stay live.


Thanks for confirming my thinking, I am much happier for a second
opinion.




The consumer units should also have shrouds on the incoming terminals,
so as long as the main switch in the CU is also off the CU won't become
live even if power was supplied unexpectedly. If I was working on the
input side of the CU, I'd be tempted to remove the main fuse anyway
(though strictly this is illegal).


It looks as though the whole CU will need replacing, the one with the
single, uncovered, MCB in the picture



It's something to be careful of in multi-rate installations that there's
often not a single switch to cut all power to the building. My house
used to have THTC, which meant there were *four* main switches
(general supply, 24 hour heating, water heating, timed heating). Unless
all four were off, something was still powered or could become powered
under timeswitch control.

Mike

That's complicated, did you have four separate incoming cables and main
fuses, or was it all done after the meter?

--

Roger Hayter


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
NEC question: low-voltage wiring crossing 120v wiring. Percival P. Cassidy Home Repair 31 October 3rd 11 01:42 PM
ATX power supply to bench supply conversion Kingcosmos Electronics Repair 5 April 4th 07 05:24 PM
Economy 7 question Ian Harding UK diy 15 December 21st 04 02:13 PM
Dishwasher Water Supply & Electric Oven Electric Supply Richard Faulkner UK diy 4 December 3rd 03 12:44 AM
Can you put a water supply pipe and a gas supply pipe in the same conduit? Suz UK diy 4 September 9th 03 04:06 AM


All times are GMT +1. The time now is 02:10 AM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017