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Topic Title: Lighting cable
Topic Summary: 1.5 & 1.0mm
Created On: 10 January 2019 08:18 PM
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 11 January 2019 10:47 AM
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Blencathra

Posts: 219
Joined: 07 November 2017

Originally posted by: Zoomup

Originally posted by: Blencathra



When I was rewiring council estates, the spec was 1.5 for lighting & 16mm tails




Yep, there was a perceived potential abuse of lighting circuits so 1.5mm2 was specified. Possibly to be more robust when aluminium kitchen foil was wrapped around a blown cartidge fuse in the fuse box.



Z.


Crabtree starbreakers AFAIK
 11 January 2019 12:10 PM
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Zoomup

Posts: 6117
Joined: 20 February 2014

Back in the days of fuse wire it was found that people would renew blown fuses with larger wire or fit a paper clip in the carrier. So, back then when M.C.B.s were not available at a sensible price, or even at all, councils had cartridge fuses fitted to fuse boxes in council houses. As the fuses were physically different in size according to rating it was assumed that the wrong fuse could not be fitted into a carrier. The smallest being 5 Amp and the common largest in size being a 30 Amp cartridge fuse. But some tenants would wrap kitchen foil around a blown cartridge fuse to save money, or where a new fuse wasn't immediately available. Rewires may have had new consumer units fitted with M.C.B.s, but presumably the 1.5mm2 lighting cable may have remained in the house, or the size retained in the rewire as it was traditionally used due to its robustness and ability to withstand abuse to a certain extent People may have added heaters to the lighting circuit years ago or run appliances from lighting points using B.C. plugs or adaptors.

Z.
 11 January 2019 12:39 PM
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Zoomup

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In the 50s and 60s two way B.C. lamp adaptors were in use in the U.K. They fitted in a ceiling light holder and allowed a bulb to be inserted in one of the outlets and the other outlet could be used for an appliance such as a clothes iron. There was no earthing provision so the earth of the clothes iron was left unconnected, a dangerous arrangement. These devices could cause overloading of lighting circuits if too many appliances were connected at once. This in the days of fuse wire and cartridge fuses.

http://www.flameport.com/elect...uble_BS52_adaptor.cs4



Z.
 11 January 2019 04:30 PM
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AJJewsbury

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In the 50s and 60s two way B.C. lamp adaptors were in use in the U.K.

I'm sure they were available a lot earlier and later than that - I remember shelf fulls of them in Woolworths when I was a kid (along with all kinds of round/flat pin adaptors) and that wasn't any earlier than the mid 1970s.

- Andy.
 11 January 2019 04:48 PM
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KFH

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Joined: 06 November 2010

I don't like using 1.0 as I find it often breaks at the accessory even when doubled. The small extra cost of 1.5 makes it worthwhile in my opinion for a more robust connection. Perhaps I am just to heavy handed.

I have a soldering iron with a bayonet plug on the end. The rubber flex has seen much better days so I don't think I will be tempted to use it anytime soon.

I certainly used the double adaptors in the 50's and can remember my mother and others ironing using an iron connected to one. As an agile youngster I was expected to climb on the chair to plug it in/unplug it. Using more than one double adaptor was not uncommon.
 11 January 2019 05:51 PM
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sparkingchip

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Originally posted by: KFH

I don't like using 1.0 as I find it often breaks at the accessory even when doubled. The small extra cost of 1.5 makes it worthwhile in my opinion for a more robust connection. Perhaps I am just to heavy handed.


Which is why 1.0 mm cable cannot be used for emergency lighting installation.

Andy Betteridge
 11 January 2019 06:17 PM
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Zoomup

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I never have any problems with 1.0mm2 breaking if it is stripped carefully. It may break at terminations if the copper is nicked by careless insulation removal. Solid copper conductors can all break if nicked, even 1.5 or 2.5mm2. Stranded conductors seemed to be more reliable as compared to single solid conductors.

Z.
 11 January 2019 06:25 PM
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Zoomup

Posts: 6117
Joined: 20 February 2014

Originally posted by: AJJewsbury

In the 50s and 60s two way B.C. lamp adaptors were in use in the U.K.


I'm sure they were available a lot earlier and later than that - I remember shelf fulls of them in Woolworths when I was a kid (along with all kinds of round/flat pin adaptors) and that wasn't any earlier than the mid 1970s.



- Andy.


Quite possibly........................ but B.S. 52:1963 covers the B.C. adaptors. I am too young to remember the 1940s though. By the 70s most homes had sufficient 13 Amp. sockets to supply appliances such as clothes irons or had trailing sockets available. The trailing clothes' iron flex from the swinging ceiling light was a thing of the past in most homes.

Z.
 11 January 2019 11:11 PM
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broadgage

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BC adaptors were in general use into the 1980s in older properties that often only had one 13 amp socket in bedrooms, and two in living rooms.
3 way versions existed, for a light bulb, the clothes iron, and a radio for example.
My late grandfather had a lead light with a BC adaptor and many yards of flex, it was plugged into the bathroom light and used to light the loft when needed.

These adaptors still have their uses, I used some a few weeks ago for Christmas lights in the local pub.
 12 January 2019 09:28 AM
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dustydazzler

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I used to have a bc adaptor with about 10m of flex on it attached to an old cage type lead light with large clamp on it take into lofts.
Very handy
 12 January 2019 10:56 AM
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mapj1

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As a point of note BS52 was the right number from about 1910 to mid 1981, as the standard got updated without changing the number, however the 1933 edition is the earliest of many outdated versions you can get from the BSI in PDF format.

Actually compared to the standard for lamp holders, the wiring regs are positively a model of stability.
BS 52:1933 Bayonet lamp-caps and metal cased bayonet lampholders not exceeding 250 volts
BS 52:1936 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors) for voltages not exceeding 250 volts
BS 52:1941. -"-
BS 52:1952 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors)
BS 52:1963 Specification for bayonet lamp-caps lampholders and B.C. adaptors (lampholder plugs)
BS 5042-1:1981 Specification for lampholders and starterholders. Bayonet lampholders
BS 5042:1987 Specification for bayonet lampholders
BS EN 61184:1995 -"-
BS EN 61184:1997, IEC 61184:1997 -"-
BS EN 61184:2008 -"-
BS EN 61184:2011 -"-
The latest is BS EN 61184:2017 Bayonet lampholders

And its already under review again, so clearly things are changing fast.
A similar thread of documents exists for edison screw lampholders, the connections for florry tubes, ELV lamps, aircraft lamps, linear lamps..

I suppose we should be pleased that we are not expected to buy up to date copies of these as well as of BS7671, all at a hundred quid or so a pop.

-------------------------
regards Mike
 12 January 2019 11:32 AM
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Zoomup

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For Sale.

Tea chest of B.C. brown plugs. Slightly dusty. Some spider and fly parts' content. Good condition. New unused old stock.

£5.00 per pound or £20.00 per gross or 2/6d each. Buyer collects.

Tel. Grimsby 227.

Z.
 12 January 2019 11:36 AM
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Zoomup

Posts: 6117
Joined: 20 February 2014

Originally posted by: mapj1

As a point of note BS52 was the right number from about 1910 to mid 1981, as the standard got updated without changing the number, however the 1933 edition is the earliest of many outdated versions you can get from the BSI in PDF format.



Actually compared to the standard for lamp holders, the wiring regs are positively a model of stability.

BS 52:1933 Bayonet lamp-caps and metal cased bayonet lampholders not exceeding 250 volts

BS 52:1936 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors) for voltages not exceeding 250 volts

BS 52:1941. -"-

BS 52:1952 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors)

BS 52:1963 Specification for bayonet lamp-caps lampholders and B.C. adaptors (lampholder plugs)

BS 5042-1:1981 Specification for lampholders and starterholders. Bayonet lampholders

BS 5042:1987 Specification for bayonet lampholders

BS EN 61184:1995 -"-

BS EN 61184:1997, IEC 61184:1997 -"-

BS EN 61184:2008 -"-

BS EN 61184:2011 -"-

The latest is BS EN 61184:2017 Bayonet lampholders



And its already under review again, so clearly things are changing fast.

A similar thread of documents exists for edison screw lampholders, the connections for florry tubes, ELV lamps, aircraft lamps, linear lamps..



I suppose we should be pleased that we are not expected to buy up to date copies of these as well as of BS7671, all at a hundred quid or so a pop.


I look forward to discussing that with my new girlfriend tonight over drinks at The Dog and Duck. I am normally stuck for words and subject matter so that info is very helpful.

Bye,

Z.
 12 January 2019 03:57 PM
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Legh

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Joined: 17 December 2004

If I remember rightly you would not want to use 1.0mm2 singles for lighting ......why? your weekend quiz question...

I had the same debate with a colleague once and it was resolved by demonstrating basic cable calcs even when derating by 50% the conductor size is still compliant...

Legh

-------------------------

http://www.leghrichardson.co.uk

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 12 January 2019 04:12 PM
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Zoomup

Posts: 6117
Joined: 20 February 2014

Originally posted by: Legh

If I remember rightly you would not want to use 1.0mm2 singles for lighting ......why? your weekend quiz question...



I had the same debate with a colleague once and it was resolved by demonstrating basic cable calcs even when derating by 50% the conductor size is still compliant...



Legh


Hello Legh,
I don't recall saying that I would not use 1.0mm2 T&E for domestic lighting circuits. I have used it for years with 5 Amp fuses or 6 Amp M.C.B.s. Perhaps you could post the quote to refresh my memory. Recently I have been saying that there is no need for normal domestic lighting circuits to have 1.5mm2 conductors. 1.5mm2 cables may be needed for long runs or larger loads though.

Z.
 12 January 2019 04:47 PM
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Legh

Posts: 4427
Joined: 17 December 2004

Nothing wrong with 1.0mm2 single core Twin & E for lighting, in fact I would recomend it for smal/domestic installations. However, I would not recomend 1.0mm2 single core singles when installed in conduit . Why?

Legh

-------------------------

http://www.leghrichardson.co.uk

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 13 January 2019 04:01 PM
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Zoomup

Posts: 6117
Joined: 20 February 2014

Originally posted by: Legh

Nothing wrong with 1.0mm2 single core Twin & E for lighting, in fact I would recomend it for smal/domestic installations. However, I would not recomend 1.0mm2 single core singles when installed in conduit . Why?



Legh


What was the answer provided at the time Legh?

Z.
 13 January 2019 05:55 PM
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mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: RB1981
In the south the cable to I.S. 201 does indeed have a full-sized, insulated cpc though.

Is it flat T&E or round?
 13 January 2019 06:11 PM
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RB1981

Posts: 513
Joined: 16 September 2007

Originally posted by: mikejumper

Originally posted by: RB1981

In the south the cable to I.S. 201 does indeed have a full-sized, insulated cpc though.



Is it flat T&E or round?


It's flat.

And with brown & Earth or blue & Earth instead of being round like the BS equivalent it is also flat.

-------------------------
Walsh Electrical Services
http://www.walshelectrical.ie/
RECI REC & NICEIC Approved Contractor
 13 January 2019 06:30 PM
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Legh

Posts: 4427
Joined: 17 December 2004

"What was the answer provided at the time Legh?"

The answer given by RB1981 states that 1.0mm2 singles appears now to be unavailable, not that I've attempted to purchase it in the last 30 years. You really wouldn't want to use it in conduit.

Legh

-------------------------

http://www.leghrichardson.co.uk

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IET » Wiring and the regulations » Lighting cable

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