Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

No.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak
wire being swtiched live.



This means only one cable is connected to the consumer unit.

Yes

I
believe a red sheath should be fitted to the black wire at the switch.


I believe its not done like that in best practice, I never have.

In the limit you need to carry live, switched-live and earth to the
switch as you have surmised, but I do not think that normal T & E colors
are used in that case.


(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.



--
Theres a mighty big difference between good, sound reasons and reasons
that sound good.

Burton Hillis (William Vaughn, American columnist)

On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak
wire being swtiched live.



This means only one cable is connected to the consumer unit.

Yes

Â* I
believe a red sheath should be fitted to the black wire at the switch.


I believe its not done like that in best practice, I never have.

In the limit you need to carry live, switched-live and earth to the
switch as you have surmised, but I do not think that normal T & E colors
are used in that case.


(*)Â* Although I refer to red and black, I appreciate these may be
brown and blue.Â* I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.


"Loop in" wiring is AFAIK (a) dead common, (b) still perfectly
acceptable and (c) what the OP seems to have.

http://wiki.diyfaq.org.uk/index.php/...Loop-in_Wiring




--
Robin
reply-to address is (intended to be) valid

On 29/09/18 10:53, Robin wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak
wire being swtiched live.



This means only one cable is connected to the consumer unit.

Yes

Â*Â* I
believe a red sheath should be fitted to the black wire at the switch.


I believe its not done like that in best practice, I never have.

In the limit you need to carry live, switched-live and earth to the
switch as you have surmised, but I do not think that normal T & E
colors are used in that case.


(*)Â* Although I refer to red and black, I appreciate these may be
brown and blue.Â* I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.


"Loop in" wiring is AFAIK (a) dead common, (b) still perfectly
acceptable and (c) what the OP seems to have.

http://wiki.diyfaq.org.uk/index.php/...Loop-in_Wiring





I am amazed.


--
Climate Change: Socialism wearing a lab coat.

The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak
wire being swtiched live.



This means only one cable is connected to the consumer unit.

Yes

Â* I
believe a red sheath should be fitted to the black wire at the switch.


I believe its not done like that in best practice, I never have.

In the limit you need to carry live, switched-live and earth to the
switch as you have surmised, but I do not think that normal T & E colors
are used in that case.


(*)Â* Although I refer to red and black, I appreciate these may be
brown and blue.Â* I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.



In Australia generally, because all lighting for quite a while has to
have an earth present they mainly run a twin +E through every light
point (A N E )and then drop a twin down to the switch from each point
for standard lighting points.
2 way requires a wire between switches.
Rarely do you need a neutral at the switch point

On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes


I think you mean NO

You obviously have a keyboard like mine with a couple of sicky eys
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.!
"The Natural Philosopher" wrote in message
news
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

No.

In genereal the cable goes from te curcuit to the stich, and then on again
to the next swich and cables are run from te switch to te light fitting.
So the switch has THREE cables entering it.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak wire
being swtiched live.



This means only one cable is connected to the consumer unit.

Yes

I
believe a red sheath should be fitted to the black wire at the switch.


I believe its not done like that in best practice, I never have.

In the limit you need to carry live, switched-live and earth to the switch
as you have surmised, but I do not think that normal T & E colors are used
in that case.


(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.



--
There's a mighty big difference between good, sound reasons and reasons
that sound good.

Burton Hillis (William Vaughn, American columnist)

On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.

Even if te light fiffing istelf carries the nain circuit it is
coinventional to run TWO cable to the switch so as NOT to have s bcak
wire being swtiched live.

That's even less common (to the point I have never seen it done)

This means only one cable is connected to the consumer unit.

Yes

Â* I
believe a red sheath should be fitted to the black wire at the switch.

Yup

I believe its not done like that in best practice, I never have.

Its is a regs requirement, since you are using a wire for a purpose its
colour would not indicate otherwise. I will agree its frequently missing
however, but it should be there.

In the limit you need to carry live, switched-live and earth to the
switch as you have surmised, but I do not think that normal T & E colors
are used in that case.

You can get a T&E with two red/brown conductors, but its rarely used
since normal colours and over marking is acceptable.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

--
Adam

On Mon, 1 Oct 2018 21:03:57 +0100, ARW
wrote:

On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?

On Monday, 1 October 2018 21:31:37 UTC+1, Scott wrote:
On Mon, 1 Oct 2018 21:03:57 +0100, ARW
wrote:

On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?

There are at least 2 ways to wire sockets


NT

Scott wrote:
Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?

Because usually things on a ring circuit don't have remote switches. If
all your lights have built in switches, there's only one way to wire a
lighting circuit. If all the sockets on your ring have separate
switches, they can be wired the same two (or three really) ways. But
lights normally have separate switches, and sockets normally don't.

A simpler version is that there's four ways to wire a switch to a
switched load:
1) The switch is built in to the end accessory.
2) "Junction box" wiring - the "main line" of the power circuit connects
to a junction box. Live goes to the switch, switched live comes back,
switched live and neutral go to the load.
3) "loop in" wiring" - the main line of the power circuit goes to the
load (light) which has an extra terminal - effectively a built-in
junction box. Live goes to the switch and switched live comes back.
4) I don't think this one has an official name - the main line of the
power circuit goes to the switch. Switched live and neutral go to the
load.

Note that two or more of these - even all four - can be mixed on a
single circuit. None are more correct than the others but some are more
common. Lighting circuits usually use 2 or 3, sometimes 4. Power
circuits use 1, though 4 is used in kitchens (where there's a switch
above the worktop and a socket below).

Mike

On 01/10/2018 21:31, Scott wrote:
On Mon, 1 Oct 2018 21:03:57 +0100, ARW
wrote:

On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?

Perhaps a better comparison with socket circuits in general rather than
a ring specifically. Then there are several ways of doing the sockets.
However socket circuits are inherently similar in that they don't
usually involve remote switching (save for a few under counter sockets
in the kitchen), or a remote load from the main termination (although
you could argue a spur is such a thing).



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"Scott" wrote in message
...
On Mon, 1 Oct 2018 21:03:57 +0100, ARW
wrote:

On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?

Because with a lighting circuit, you can loop thru the roses or loop thru
the
switches. There is no equivalent with a ring main, the ring main is the
loop.

On 01/10/18 21:31, Scott wrote:

Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?


There's at least 3 general ways:

1) Ceiling rose loopin-loopout. Supply goes from rose to rose. Switch
drop goes from rose to switch.

Pro: Simple, easy to get at, roses have all the terminals needed.

Con: Works if you like having nothing but flex drop lights.
Random other light fittings may not have the space needed for all the
terminations.

2) Switch loopin-loopout. Seen this once. Works with deeper backboxes.
Needs a loose connector for the neutral. Not common IME.

Pro: Accessible
Con: Generally 3+ cables to any given switch. Adds a lot to the overall
cable length from end to end.

3) Star wired from junction boxes (what I did). 4 sets of boxes in
accessible attic locations. Very uncommon in the UK, though I think some
countries do this more.

Pro: All terminals accessible and very easy to modify.
Very good if you want to include remote control modules for
ZWave(etc) which is why I did it like this.
Con: More cable

On 01/10/2018 21:31, Scott wrote:


Why are there several ways to wire a lighting circuit when there is
only one way to wire a ring main?


I would suggest that this is down to the use of historic cables.

When electric was first introduced into houses it was quite common to
use conduit and the cotton covered cables in singles.

When T&E came alone the use of conduit disappeared and the loop in loop
out at the light fitting became the preferred method. With the conduit
method, to save cable and conduit space you would loop the permanent
live at the switches and the neutral at the lights. However singles
wiring was still carried on by some electricians who liked it (the
picture Terry Casey drew the picture for in the Wiki
http://wiki.diyfaq.org.uk/index.php/...ngle_.26_Earth)



--
Adam

On 01/10/2018 21:03, ARW wrote:
On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire.Â* The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Probably the influence of lots of imported fancy light fittings with
inadequate terminal space for traditional loop in style wiring, and
demise of the common ceiling rose.

I find switch loop through quite handy for surface wiring applications,
and exterior lights, where a single cable connection is neater.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"ARW" wrote in message
...
On 29/09/2018 19:17, John Rumm wrote:
On 29/09/2018 10:04, The Natural Philosopher wrote:
On 29/09/18 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)?

Yes

All the action takes place on the red (*)
wire.
Yes

In each room there are two drop cables: one to the switch and
one to the light fitting.

Yes ot no depending

The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

No.

Erm, yes! That's the way most loop-in systems are wired. Ideally with
some coloured sleeving over the neutral wires where they are being
re-purposed as switched lives.

In genereal the cable goes from te curcuit to the stich, and then on
again to the next swich and cables are run from te switch to te light
fitting. So the switch has THREE cables entering it.

That is another method ("switch loop in"), but its far less common.


Becoming more common all the time.

Any idea why it is becoming more common ?

On Tue, 2 Oct 2018 09:32:39 +1000, cantankerous trolling senile geezer Rot
Speed blabbered, again:



Becoming more common all the time.

Any idea why it is becoming more common ?

YOU tell us, Mr Know-it-all! BG

--
dennis@home to know-it-all Rot Speed:
"You really should stop commenting on things you know nothing about."
Message-ID:

On 29/09/2018 09:29, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.



There are various ways to do lighting

http://wiki.diyfaq.org.uk/index.php/...Loop-in_Wiring

it is though just usually a radial from the CU.

--
Adam

Ahem, there are always live and neutral in all my ceiling roses even if the
switch is off, and to me this disproves your hypothesis completely

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

Blind user, so no pictures please
Note this Signature is meaningless.!
"Scott" wrote in message
...
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

On Sat, 29 Sep 2018 17:03:41 +0100, "Brian Gaff"
wrote:

Ahem, there are always live and neutral in all my ceiling roses even if the
switch is off, and to me this disproves your hypothesis completely

Depends on your interpretation of my hypothesis. When I said the
action takes place on the red, I did not mean no return path was
needed. I do have some clue about electricity. I meant the
'diversion' and switching takes place on the red.

On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

Pretty much. The other way to do it is run the T&E from the CU to each switch, then T&E carrying E, N, switched L to the light fitting.


NT

In article ,
writes
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

Pretty much. The other way to do it is run the T&E from the CU to each
switch, then T&E carrying E, N, switched L to the light fitting.


NT
Would you believe I have both in my house. The old original part is L
and N to the ceiling rose. The extension was wired to the switch. Done
by a fully certified electrician of course - well actually done by his
apprentice, about the same standard as Adams. I had to go round a
tighten up at least 3 connections within the week.
--
bert

On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three plate/terminal" ceiling roses when live, neutral and switch wire is present.

Normally the L+N goes from CU to nearest ceiling rose to the next until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

On Tue, 2 Oct 2018 00:26:28 -0700 (PDT), harry
wrote:

On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:
Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three plate/terminal" ceiling roses when live, neutral and switch wire is present.

Normally the L+N goes from CU to nearest ceiling rose to the next until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

Thanks. It's getting complicated so I'm going to 'clone' what's there
already (and stand well clear!).

On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three plate/terminal" ceiling roses when live, neutral and switch wire is present.

Normally the L+N goes from CU to nearest ceiling rose to the next until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

The point of rings, other than using thinner cable, is safety & reliability..

If we weren't buried in red tape the UK would probably switch to bell wire for lighting with thicker insulation. The ubiquity of LED & CFL bulbs makes 100w per fitting an obsolete requirement. The widespread use of double insulated fittings & RCDs along with an all time total of 1 death from a light fitting shock makes lighting earthing redundant.


NT

On 02/10/18 12:03, wrote:

If we weren't buried in red tape the UK would probably switch to bell wire for lighting with thicker insulation. The ubiquity of LED & CFL bulbs makes 100w per fitting an obsolete requirement. The widespread use of double insulated fittings & RCDs along with an all time total of 1 death from a light fitting shock makes lighting earthing redundant.

You still need to be able to trip a 6A type B breaker in 0.4S (typical
lighting circuit, not all possible permitted) - and bell wire isn;t
going to do that. Given 1mm2 is pretty small and the CPC takes almost no
space, it would seem to be an unnecessary change.

On Tuesday, 2 October 2018 14:24:28 UTC+1, Tim Watts wrote:
On 02/10/18 12:03, tabbypurr wrote:

If we weren't buried in red tape the UK would probably switch to bell wire for lighting with thicker insulation. The ubiquity of LED & CFL bulbs makes 100w per fitting an obsolete requirement. The widespread use of double insulated fittings & RCDs along with an all time total of 1 death from a light fitting shock makes lighting earthing redundant.

You still need to be able to trip a 6A type B breaker in 0.4S (typical
lighting circuit, not all possible permitted) - and bell wire isn;t
going to do that.

no, it needs to be able to trip a 1A breaker in 0.4s. Or 1.5A etc.


Given 1mm2 is pretty small and the CPC takes almost no
space, it would seem to be an unnecessary change.

the lighting cpc is redundant now. The outer insulation is redundant as long as the cable stays hidden in walls, floor spaces etc. Its wasted cost, materials, fuel, emissions etc. No-one plugs their iron into the bulb socket anymore.


NT

On 02/10/18 19:50, wrote:
On Tuesday, 2 October 2018 14:24:28 UTC+1, Tim Watts wrote:
On 02/10/18 12:03, tabbypurr wrote:

If we weren't buried in red tape the UK would probably switch to bell wire for lighting with thicker insulation. The ubiquity of LED & CFL bulbs makes 100w per fitting an obsolete requirement. The widespread use of double insulated fittings & RCDs along with an all time total of 1 death from a light fitting shock makes lighting earthing redundant.

You still need to be able to trip a 6A type B breaker in 0.4S (typical
lighting circuit, not all possible permitted) - and bell wire isn;t
going to do that.

no, it needs to be able to trip a 1A breaker in 0.4s. Or 1.5A etc.

Tell me - where do you buy these 1A Type B CU breakers?

the lighting cpc is redundant now. The outer insulation is redundant as long as the cable stays hidden in walls, floor spaces etc. Its wasted cost, materials, fuel, emissions etc. No-one plugs their iron into the bulb socket anymore.


The main purpose of the the sheath is to protect the *insulation* on the
conductors - especially during install when the cable is rough handled,
pulled through splintery holes, clipped to rough masonry etc.

There is no way getting rid of the sheath is a good idea.

On 02/10/2018 12:03, wrote:

The point of rings, other than using thinner cable, is safety &
reliability.

If we weren't buried in red tape the UK would probably switch to bell
wire for lighting with thicker insulation.

Can't see any advantage... one of the things you require from any fixed
cable is some physical robustness. 1.0mm^2 T&E is a sensible minimum.

The ubiquity of LED & CFL
bulbs makes 100w per fitting an obsolete requirement.

Nonsense. A standard 6' linear fluorescent is 58W, and twin fittings are
common. There are also other things that get run from light circuits
like small bathroom heaters, extractor fans etc. So the capacity to
support 100W at a fitting is still quite reasonable,

The widespread
use of double insulated fittings & RCDs along with an all time total
of 1 death from a light fitting shock makes lighting earthing
redundant.

That's just daft. Class I light fittings are common. Plus your normal
pet hobby horse of assuming the only bad thing that counts is instant
death by electrocution.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 02/10/2018 21:54, John Rumm wrote:
On 02/10/2018 12:03, wrote:

The point of rings, other than using thinner cable, is safety &
reliability.

If we weren't buried in red tape the UK would probably switch to bell
wire for lighting with thicker insulation.

Can't see any advantage... one of the things you require from any fixed
cable is some physical robustness. 1.0mm^2 T&E is a sensible minimum.

The ubiquity of LED & CFL
bulbs makes 100w per fitting an obsolete requirement.

Nonsense. A standard 6' linear fluorescent is 58W, and twin fittings are
common.

My LED tube as 36W.

On 02/10/2018 22:03, dennis@home wrote:
On 02/10/2018 21:54, John Rumm wrote:
On 02/10/2018 12:03, wrote:

The point of rings, other than using thinner cable, is safety &
reliability.

If we weren't buried in red tape the UK would probably switch to bell
wire for lighting with thicker insulation.

Can't see any advantage... one of the things you require from any
fixed cable is some physical robustness. 1.0mm^2 T&E is a sensible
minimum.

The ubiquity of LED & CFL
bulbs makes 100w per fitting an obsolete requirement.

Nonsense. A standard 6' linear fluorescent is 58W, and twin fittings
are common.

My LED tube as 36W.

and those LED tapes can be over 70W for a 5m one...



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tuesday, 2 October 2018 21:54:27 UTC+1, John Rumm wrote:
On 02/10/2018 12:03, tabbypurr wrote:

The point of rings, other than using thinner cable, is safety &
reliability.

If we weren't buried in red tape the UK would probably switch to bell
wire for lighting with thicker insulation.

Can't see any advantage...

reducing cost. Doing so gets us an ever better material standard of living year on year, and enables more to be spent on the nhs etc.

one of the things you require from any fixed
cable is some physical robustness. 1.0mm^2 T&E is a sensible minimum.

depends what you're doing with it. There are many cases where bell wire is strong enough.

The ubiquity of LED & CFL
bulbs makes 100w per fitting an obsolete requirement.

Nonsense. A standard 6' linear fluorescent is 58W, and twin fittings are
common. There are also other things that get run from light circuits
like small bathroom heaters, extractor fans etc. So the capacity to
support 100W at a fitting is still quite reasonable,

those can go on 5A circuits

The widespread
use of double insulated fittings & RCDs along with an all time total
of 1 death from a light fitting shock makes lighting earthing
redundant.

That's just daft. Class I light fittings are common.

but not any significant risk. Time has proven that. And now we have een more safety protection on lighting circuits than in the decades that proved them not a problem

Plus your normal
pet hobby horse of assuming the only bad thing that counts is instant
death by electrocution.

whoosh. Death rates are used partly because it's the one thing we have genuine reasonably reliable data on.


NT

On 02/10/2018 23:59, wrote:
On Tuesday, 2 October 2018 21:54:27 UTC+1, John Rumm wrote:


Plus your normal
pet hobby horse of assuming the only bad thing that counts is instant
death by electrocution.

whoosh. Death rates are used partly because it's the one thing we have genuine reasonably reliable data on.

999 Emergency : "what service do you require?"

Nige : "Ambulance and quick, I am in so much pain!"

999 Emergency : "What is the nature of your problem?"

Nige : "I was looking for something in my loft, balancing on a joist,
and put my hand on a pipe to steady myself. Anyway it turns out some
tightwad wired my lights in bell wire, and I must have stood on the
cable and broke it. All of a sudden there was a bang, and I got a
massive shock, my trousers caught fire, and my ******** exploded!"

999 Emergency : "OK keep calm, we have completed the triage process and
can confirm that there is nothing to worry about. Since you are
obviously not dead your injury is classed as statistically unreliable
and probably not genuine. So we will not dispatch an ambulance at this
time."

999 Emergency : "If the problem worsens, say for example the fire in
your trousers were to spread to the structure of your house, then please
call 999 again and ask for the fire service. Thank you for calling 999,
and have a nice day. click".




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tuesday, 2 October 2018 12:03:16 UTC+1, wrote:
On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three plate/terminal" ceiling roses when live, neutral and switch wire is present.

Normally the L+N goes from CU to nearest ceiling rose to the next until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

The point of rings, other than using thinner cable, is safety & reliability.



The 30a ring main for sockets was devised post WW2 to save copper which was in short supply.

The big safety feature is the individual fuse in every plug.

It is in fact less reliable as all your sockets are on one fuse/MCB.

A few years back, the EUSSR was trying to make us go back to similar system to that we had abandoned in the name of "harmonisation".

In article , harry
wrote:
On Tuesday, 2 October 2018 12:03:16 UTC+1, wrote:
On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit
is linear (not a ring main)? All the action takes place on the red
(*) wire. In each room there are two drop cables: one to the
switch and one to the light fitting. The electricity goes from the
ceiling to the switch then back to the light fitting (via the
black) then through the light bulb to the main black wire. The
same is repeated in each room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the
switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three
plate/terminal" ceiling roses when live, neutral and switch wire is
present.

Normally the L+N goes from CU to nearest ceiling rose to the next
until the last/most remote one and then stops.

But in principle you could wire a ring main. However, the currents
involved are so low it would be pointless. Especially these days with
LED lights.

The point of rings, other than using thinner cable, is safety &
reliability.



The 30a ring main for sockets was devised post WW2 to save copper which
was in short supply.

The big safety feature is the individual fuse in every plug.

It is in fact less reliable as all your sockets are on one fuse/MCB.

They don't have to be.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 03/10/2018 08:32, charles wrote:
In article , harry
wrote:
On Tuesday, 2 October 2018 12:03:16 UTC+1, wrote:
On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit
is linear (not a ring main)? All the action takes place on the red
(*) wire. In each room there are two drop cables: one to the
switch and one to the light fitting. The electricity goes from the
ceiling to the switch then back to the light fitting (via the
black) then through the light bulb to the main black wire. The
same is repeated in each room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the
switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three
plate/terminal" ceiling roses when live, neutral and switch wire is
present.

Normally the L+N goes from CU to nearest ceiling rose to the next
until the last/most remote one and then stops.

But in principle you could wire a ring main. However, the currents
involved are so low it would be pointless. Especially these days with
LED lights.

The point of rings, other than using thinner cable, is safety &
reliability.



The 30a ring main for sockets was devised post WW2 to save copper which
was in short supply.

The big safety feature is the individual fuse in every plug.

It is in fact less reliable as all your sockets are on one fuse/MCB.

They don't have to be.


They do, every join makes a circuit less reliable.

A ring with one socket may be more reliable than a star with one socket
but that's about it.

The biggest problem with rings is latent faults, they continue to
operate even when the ring is broken but the user can't tell its faulty.
Then you have two radials protected by a 32A breaker which is not
allowed as its dangerous.

If you have a fault in a radial then something won't work and the user
will probably notice and get it fixed.

There are probably hundred if not thousands of broken rings out there.

I have one here but I fused it as a radial to make it safe.
The fault is in a wall and I can't be bothered to replace the cable ATM.

On Wednesday, 3 October 2018 08:02:04 UTC+1, harry wrote:
On Tuesday, 2 October 2018 12:03:16 UTC+1, tabby wrote:
On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit is
linear (not a ring main)? All the action takes place on the red (*)
wire. In each room there are two drop cables: one to the switch and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then through
the light bulb to the main black wire. The same is repeated in each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three plate/terminal" ceiling roses when live, neutral and switch wire is present.

Normally the L+N goes from CU to nearest ceiling rose to the next until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

The point of rings, other than using thinner cable, is safety & reliability.



The 30a ring main for sockets was devised post WW2 to save copper which was in short supply.

that and the ability of the average practical householder to add new sockets were the main drivers at the time. Safety was also a consideration. The safety upside is maybe more significant today.


The big safety feature is the individual fuse in every plug.

not really, but it's a plus.

It is in fact less reliable as all your sockets are on one fuse/MCB.

Rings turn a high resistance connection fault from a fire into a nonevent. That's their prime plus point.


A few years back, the EUSSR was trying to make us go back to similar system to that we had abandoned in the name of "harmonisation".


NT

wrote in message
...
On Wednesday, 3 October 2018 08:02:04 UTC+1, harry wrote:
On Tuesday, 2 October 2018 12:03:16 UTC+1, tabby wrote:
On Tuesday, 2 October 2018 08:26:30 UTC+1, harry wrote:
On Saturday, 29 September 2018 09:29:57 UTC+1, Scott wrote:

Simplistically, am I right in understanding that a lighting circuit
is
linear (not a ring main)? All the action takes place on the red
(*)
wire. In each room there are two drop cables: one to the switch
and
one to the light fitting. The electricity goes from the ceiling to
the switch then back to the light fitting (via the black) then
through
the light bulb to the main black wire. The same is repeated in
each
room.

This means only one cable is connected to the consumer unit. I
believe a red sheath should be fitted to the black wire at the
switch.

(*) Although I refer to red and black, I appreciate these may be
brown and blue. I have ignored the earth but I assume every earth
should be connected to every other earth at every opportunity.

The question only makes sense if the circuit is wired using "three
plate/terminal" ceiling roses when live, neutral and switch wire is
present.

Normally the L+N goes from CU to nearest ceiling rose to the next
until the last/most remote one and then stops.

But in principle you could wire a ring main.
However, the currents involved are so low it would be pointless.
Especially these days with LED lights.

The point of rings, other than using thinner cable, is safety &
reliability.



The 30a ring main for sockets was devised post WW2 to save copper which
was in short supply.

that and the ability of the average practical householder to add new
sockets were the main drivers at the time. Safety was also a
consideration. The safety upside is maybe more significant today.


The big safety feature is the individual fuse in every plug.

not really, but it's a plus.

It is in fact less reliable as all your sockets are on one fuse/MCB.

Rings turn a high resistance connection fault from a fire into a nonevent.

Spurs dont catch fire with a high resistance connection fault.

That's their prime plus point.

Wrong when spurs do too.

A few years back, the EUSSR was trying to make us go back to similar
system to that we had abandoned in the name of "harmonisation".