I replaced a standard light pendant and although everything works I am
slightly confused about the light circuit. The celing rose consists of
three separate cables (one double core, the other two both single
core). One of the double core cables goes to the live junction in the
ceiling rose the other to the earth connection. Both single core
cables (twisted together) go to one of the neutral junction terminals
(nothing goes into the loop section of the ceiling rose).

The only idea I came up with is that the neutral loops round all the
ceiling roses and the same thing happens on the live side in the
switches (which in the room where I replaced the pendant also has
three separate wires going into the switch). So I have a ring lighting
circuit?

But again I am not sure so any suggestions are welcome

Thanks

Nick

Nick

Is your house 1970's ish construction?
I have a property of that period similarly wired.
Live loops around switches, neutral between ceiling roses - quite confusing
till you get your head round it!
Wouldn't suprise me if this was done for cheapness.
With new additions to mine, I've tended to adopt modern wiring protocols
(rightly or wrongly).

Phil

On 29 Jan 2004 04:44:05 -0800, (Nick) wrote:

I replaced a standard light pendant and although everything works I am
slightly confused about the light circuit. The celing rose consists of
three separate cables (one double core, the other two both single
core). One of the double core cables goes to the live junction in the
ceiling rose the other to the earth connection. Both single core
cables (twisted together) go to one of the neutral junction terminals
(nothing goes into the loop section of the ceiling rose).

The only idea I came up with is that the neutral loops round all the
ceiling roses and the same thing happens on the live side in the
switches (which in the room where I replaced the pendant also has
three separate wires going into the switch). So I have a ring lighting
circuit?

But again I am not sure so any suggestions are welcome

You don't get ring lighting circuits, except for some industrial
situations.
What you have is the neutral feeding all of the lighting points in a
radial configuration.
The lives loop around all of the switches in a radial configuration.
Then from each switch a single live switch wire is taken to the light
point.
The three seperate wires in your switch, (assuming you have 1 light
point in the room in question), would be - 2x live feed and 1x live
switch wire.
The last light on the circuit would have 1x neutral in the light point
and 2x live in the switch, (1x feed and 1x switchwire).


SJW
A.C.S. Ltd.

On Thu, 29 Jan 2004 13:52:26 -0000, "TheScullster"
wrote:

Nick

Is your house 1970's ish construction?
I have a property of that period similarly wired.
Live loops around switches, neutral between ceiling roses - quite confusing
till you get your head round it!
Wouldn't suprise me if this was done for cheapness.
With new additions to mine, I've tended to adopt modern wiring protocols
(rightly or wrongly).

That is modern protocol, just not as common as the 'loop-in' method.
It's not wrong, just different. It's a lot easier, both on 1st and 2nd
fix, always has been, always will be. I find it a lot easier to do it
that way, especially when there are quite a few different switching
and lighting arrangements in one area.


SJW
A.C.S. Ltd.

In article , Lurch wrote:
I have a property of that period similarly wired.
Live loops around switches, neutral between ceiling roses -
quite confusing till you get your head round it!
Wouldn't suprise me if this was done for cheapness.
With new additions to mine, I've tended to adopt modern
wiring protocols (rightly or wrongly).

That is modern protocol, just not as common as the 'loop-in'
method. It's not wrong, just different.

It sounds less than wise to me, because you end up with
unbalanced currents in different cables. Wouldn't this do
undesirable things where the cable was (say) in a length of
metal conduit?

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm

On Thu, 29 Jan 2004 14:42:00 GMT, Tony Bryer
wrote:

In article , Lurch wrote:
I have a property of that period similarly wired.
Live loops around switches, neutral between ceiling roses -
quite confusing till you get your head round it!
Wouldn't suprise me if this was done for cheapness.
With new additions to mine, I've tended to adopt modern
wiring protocols (rightly or wrongly).

That is modern protocol, just not as common as the 'loop-in'
method. It's not wrong, just different.

It sounds less than wise to me, because you end up with
unbalanced currents in different cables. Wouldn't this do
undesirable things where the cable was (say) in a length of
metal conduit?

Basically, no. Off the top of my head it could get a little complex
trying to explain here, I might come back later!
If anyone else wants to have a go in the meantime then go ahead.


SJW
A.C.S. Ltd.

"Nick" wrote in message
m...
I replaced a standard light pendant and although everything works I am
slightly confused about the light circuit. The celing rose consists of
three separate cables (one double core, the other two both single
core). One of the double core cables goes to the live junction in the
ceiling rose the other to the earth connection. Both single core
cables (twisted together) go to one of the neutral junction terminals
(nothing goes into the loop section of the ceiling rose).

The only idea I came up with is that the neutral loops round all the
ceiling roses and the same thing happens on the live side in the
switches (which in the room where I replaced the pendant also has
three separate wires going into the switch). So I have a ring lighting
circuit?

But again I am not sure so any suggestions are welcome

Thanks

Nick

These any help:

http://www.dablighting.co.uk/lightwiring.html

http://www.diydata.com/planning/elec...ric_lights.htm


---
http://www.basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.572 / Virus Database: 362 - Release Date: 27/01/04

That is modern protocol, just not as common as the 'loop-in' method.
It's not wrong, just different.

It is wrong. It probably should be banned under some sort of Disability
Discrimination Act. It will totally bugger up any hearing aid inductive
loops when the lights are turned on. When routing cables, you should always
ensure that the current flows are balanced as much as possible. This can be
difficult for central heating systems if the wiring's all over the place,
but easy enough to do with lighting, provided you take care with any 3 way
lighting to only feed at one end and don't loop neutrals separately from
lives.

Christian.

In article ,
Tony Bryer writes:
In article , Lurch wrote:
I have a property of that period similarly wired.
Live loops around switches, neutral between ceiling roses -
quite confusing till you get your head round it!
Wouldn't suprise me if this was done for cheapness.
With new additions to mine, I've tended to adopt modern
wiring protocols (rightly or wrongly).

That is modern protocol, just not as common as the 'loop-in'
method. It's not wrong, just different.

It sounds less than wise to me, because you end up with
unbalanced currents in different cables. Wouldn't this do
undesirable things where the cable was (say) in a length of
metal conduit?

Yes, it's not allowed in steel conduit. In theory it
causes edie current heating if the wires enter steel back
boxes through different punchouts, but I doubt it will be
significant enough to notice at domestic lighting circuit
current levels.

Another reason you aren't supposed to do it is it stops
induction loop hearing aids working, and this can affect
neighbouring properties too. Unbalanced wiring layout
of 2-way switched landing lights is a common cause of this
problem.

--
Andrew Gabriel

On Thu, 29 Jan 2004 16:13:32 -0000, "Christian McArdle"
wrote:

That is modern protocol, just not as common as the 'loop-in' method.
It's not wrong, just different.

It is wrong. It probably should be banned under some sort of Disability
Discrimination Act. It will totally bugger up any hearing aid inductive
loops when the lights are turned on. When routing cables, you should always
ensure that the current flows are balanced as much as possible. This can be
difficult for central heating systems if the wiring's all over the place,
but easy enough to do with lighting, provided you take care with any 3 way
lighting to only feed at one end and don't loop neutrals separately from
lives.

It's not wrong, it is the same as running the lives from the rose to
the switch, its just that this method bypasses the rose.
If it was to be banned you would have to ban all types of 'unbalanced'
cabling, e.g. singles, 3 phase and anything else that doesnt carry the
same current on the neutral returned as the live feeding it. This
would also include regular loop-in methods.


SJW
A.C.S. Ltd.

It's not wrong, it is the same as running the lives from the rose to
the switch, its just that this method bypasses the rose.

No it isn't. In a loop in system, the power feeds are balanced. The switch
drops are balanced. It is all balanced.

If it was to be banned you would have to ban all types of 'unbalanced'
cabling, e.g. singles, 3 phase and anything else that doesnt carry the
same current on the neutral returned as the live feeding it.

Indeed. In a domestic setting, unbalanced cabling is simply not required and
will cause considerable distress and discomfort to hearing aid users.

In what way would 3 phase in one cable not be balanced? (Without tripping
the RCD due to an earth fault). You don't even need a neutral to balance it,
although if a neutral is used as a live conductor, it MUST also be present
in the cable.

Singles, indeed, should be used with caution (i.e. only if T&E is not
available for the cross sectional area) and routed adjacent with the other
cables of the circuit to reduce imbalance. The closer the better, provided
that cable grouping derating allows it.

Christian.

On Thu, 29 Jan 2004 16:55:54 -0000, "Christian McArdle"
wrote:

It's not wrong, it is the same as running the lives from the rose to
the switch, its just that this method bypasses the rose.

No it isn't. In a loop in system, the power feeds are balanced. The switch
drops are balanced. It is all balanced.

Actually, now I think about it...yes!

If it was to be banned you would have to ban all types of 'unbalanced'
cabling, e.g. singles, 3 phase and anything else that doesnt carry the
same current on the neutral returned as the live feeding it.

Indeed. In a domestic setting, unbalanced cabling is simply not required and
will cause considerable distress and discomfort to hearing aid users.

In what way would 3 phase in one cable not be balanced? (Without tripping
the RCD due to an earth fault). You don't even need a neutral to balance it,
although if a neutral is used as a live conductor, it MUST also be present
in the cable.

If a TP&N supply was feeding a DB that was feeding a mixture of
balanced TP and SP loads the supply cable to the TP DB would be
unbalanced between L1,L2,L3 & N.

Singles, indeed, should be used with caution (i.e. only if T&E is not
available for the cross sectional area) and routed adjacent with the other
cables of the circuit to reduce imbalance. The closer the better, provided
that cable grouping derating allows it.

No-one says the wiring methods adopted are perfect in all situations,
that's why careful selection of the best method for the installation
is required.
In a domestic situation it is highly unlikely to have a induction loop
system fitted.
If you were going on the basis of making all homes 100% disability
friendly you would have to get rid of all stairs, sharp corners,
steps, visible only warnings etc...
I think the term 'reasonable expectations' would apply to all
installations.


SJW
A.C.S. Ltd.

If a TP&N supply was feeding a DB that was feeding a mixture of
balanced TP and SP loads the supply cable to the TP DB would be
unbalanced between L1,L2,L3 & N.

It will remain balanced, provided all live conductors (including any active
neutral) go through the same cable.

Take a 3+E cable. Draw off red phase, you get current through the red and
return current through the black. Balanced. You can do the same for any
other phase.

You can draw current through multiple phases at the same time and it will
remain balanced. As the phases are out of phase (strangely), the value of
the current in the neutral doesn't just get bigger as you add current. Some
of the red phase return path may go down the blue/yellow phase instead, for
example.

Indeed, if you draw the same current through each phase, it still remains
balanced, although the neutral current drops to zero! A 3 phase motor will
typically not require the neutral as it draws equally from each phase.

In any case, I see no reason why the electrons going up the 4 conductors
doesn't match the number of electrons coming back, unless they're falling
out of the cable somewhere, or there is a separate conductive path, such as
an earth fault or external neutral.

To be balanced DOESN'T require the same current in all the phase conductors,
just the total current vector in all conductors to add to zero. If it
didn't, a 4P RCD would trip!

Christian.

In a domestic situation it is highly unlikely to have a induction loop
system fitted.

I can assure you it is not. Many hearing aid users have modified telephones,
or induction loops for television watching within their homes. These devices
are cheap and widely available.

I think the term 'reasonable expectations' would apply to all
installations.

Indeed. I think it is unreasonable to install an unbalanced lighting system
that may have interference effects over a wide area, including your
neighbour's property, who may not be able to use their telephone or watch TV
and certainly are unable to go into your house to fix the circuit.

Christian.

On Thu, 29 Jan 2004 17:31:10 -0000, "Christian McArdle"
wrote:

If a TP&N supply was feeding a DB that was feeding a mixture of
balanced TP and SP loads the supply cable to the TP DB would be
unbalanced between L1,L2,L3 & N.

It will remain balanced, provided all live conductors (including any active
neutral) go through the same cable.

Take a 3+E cable. Draw off red phase, you get current through the red and
return current through the black. Balanced. You can do the same for any
other phase.

You can draw current through multiple phases at the same time and it will
remain balanced. As the phases are out of phase (strangely), the value of
the current in the neutral doesn't just get bigger as you add current. Some
of the red phase return path may go down the blue/yellow phase instead, for
example.

Indeed, if you draw the same current through each phase, it still remains
balanced, although the neutral current drops to zero! A 3 phase motor will
typically not require the neutral as it draws equally from each phase.

In any case, I see no reason why the electrons going up the 4 conductors
doesn't match the number of electrons coming back, unless they're falling
out of the cable somewhere, or there is a separate conductive path, such as
an earth fault or external neutral.

To be balanced DOESN'T require the same current in all the phase conductors,
just the total current vector in all conductors to add to zero. If it
didn't, a 4P RCD would trip!

Hmmm...
Anyway, I've never come across a problem with induction loops in a
commercial property, wired in singles, twin or any other method.
Nor have I even come across an induction loop in a house, I'm not
saying none of the above happen but the likelihood... I'll leave that
one to personal choice.


SJW
A.C.S. Ltd.

Anyway, I've never come across a problem with induction loops in a
commercial property, wired in singles, twin or any other method.

Singles will OK, if run together. It is separation of the conductors that
matters. Splitting phases doesn't matter if the only return path (i.e. the
neutral) goes with it.

Christian.

In message ,
"Christian McArdle" wrote:

In a domestic situation it is highly unlikely to have a induction loop
system fitted.

I can assure you it is not. Many hearing aid users have modified telephones,
or induction loops for television watching within their homes. These devices
are cheap and widely available.


Much as I hate reading "me too"s, point seconded. All NHS-supplied and
many private hearing aids have the ability to be switched to "loop" mode
(usually a "T" position on an analogue aid). This can be a great help
when listening to the telephone, and, as you say, "personal" loops are
available for, for example, television watching.

One in seven of the population of Britain is medically classed as
"deaf", though obviously the amount of loss varies considerably. That
means that in my row of a dozen houses, at least one, and probably two
of them will have a deaf person living there.

I think the term 'reasonable expectations' would apply to all
installations.

Indeed. I think it is unreasonable to install an unbalanced lighting system
that may have interference effects over a wide area, including your
neighbour's property, who may not be able to use their telephone or watch TV
and certainly are unable to go into your house to fix the circuit.


TBH I've found that the OSG's recommended two-way switching circuit is
easier to understand and dead easy to install when compared with the
older way of doing things. The switch nearest the lamp is wired in
almost the normal way (permanent live goes in a different hole), and you
run a three+E to the other switch(es).

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... KLEPTOMANIA! Take something for it!

One in seven of the population of Britain is medically classed as
"deaf", though obviously the amount of loss varies considerably. That
means that in my row of a dozen houses, at least one, and probably two
of them will have a deaf person living there.

I'm 1/2 deaf.

I think the term 'reasonable expectations' would apply to all
installations.

Indeed. I think it is unreasonable to install an unbalanced lighting system
that may have interference effects over a wide area, including your
neighbour's property, who may not be able to use their telephone or watch TV
and certainly are unable to go into your house to fix the circuit.


TBH I've found that the OSG's recommended two-way switching circuit is
easier to understand and dead easy to install when compared with the
older way of doing things. The switch nearest the lamp is wired in
almost the normal way (permanent live goes in a different hole), and you
run a three+E to the other switch(es).

It's all easy when you do it every day!


SJW
A.C.S. Ltd.

In message ,
(Lurch) wrote:

One in seven of the population of Britain is medically classed as
"deaf", though obviously the amount of loss varies considerably. That
means that in my row of a dozen houses, at least one, and probably two
of them will have a deaf person living there.

I'm 1/2 deaf.

I think the term 'reasonable expectations' would apply to all
installations.

Indeed. I think it is unreasonable to install an unbalanced lighting system
that may have interference effects over a wide area, including your
neighbour's property, who may not be able to use their telephone or watch TV
and certainly are unable to go into your house to fix the circuit.


TBH I've found that the OSG's recommended two-way switching circuit is
easier to understand and dead easy to install when compared with the
older way of doing things. The switch nearest the lamp is wired in
almost the normal way (permanent live goes in a different hole), and you
run a three+E to the other switch(es).

It's all easy when you do it every day!


I do! It's just that the "engineer" in me sees a greater beauty and
symmetry in the method described in the OSG, just as it sees the same in
the normal switch-drop method :-)

Given the low current usually involved in lighting the
hall/stairs/landing though, and the distance of the circuit wires from
the television (normally) I wonder just how much potential for
interference there really is... but when the solution is so simple, it
isn't worth not doing it, is it?

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... Even if you're not, be brave, no one can tell the difference.