Indicator switch with no neutral?

[marconi]

I am just heading out the door but you are right that more turns will be required for the lower load current of your application. To light the LED requires 0.75 AmpTurns of alternating magnetic flux. As long as the product of load current multiplied by number of turns equals 0.75Aturns then the LED will illuminate.

 

[marconi]

"Colin33, post: 1410887, member: 18528"]I have a similar situation whereby I need to light an indicator lamp when the outside lights are left on. Problem is, the outside lights comprise of 2 x 5w GU10's. I assume this means passing the wire through the hole around 18 times, is that correct, and doable with a 1mm cable?[/I]

The CT's hole is 9mm diameter. The diameter figure I turn up for solid single core insulated 1mm2 is in the range 2.1 to 2.5mm. I reckon this will pass through at most 12-13 times. So, you you will have to use a lower csa flex - say 0.5 mm2- and protect it with a 1 A fuse and mark up this maximum fuse size - see:

1 Amp Plug Fuse - BS1362 - https://www.tlc-direct.co.uk/Products/TLF1.html

http://www.batt.co.uk/upload/files/4f3a_1231500485.pdf

If it was me, I'd see if 12 turns of 1 mm2 provided sufficient LED illumination and if not then use the 0.5mm2 flex and 1A fuse method.

Sorry for the delay in answering this last part of your post.

 

[Colin33]

The CT's hole is 9mm diameter. The diameter figure I turn up for solid single core insulated 1mm2 is in the range 2.1 to 2.5mm. I reckon this will pass through at most 12-13 times. So, you you will have to use a lower csa flex - say 0.5 mm2- and protect it with a 1 A fuse and mark up this maximum fuse size - see:

1 Amp Plug Fuse - BS1362 - https://www.tlc-direct.co.uk/Products/TLF1.html

http://www.batt.co.uk/upload/files/4f3a_1231500485.pdf

If it was me, I'd see if 12 turns of 1 mm2 provided sufficient LED illumination and if not then use the 0.5mm2 flex and 1A fuse method.

Sorry for the delay in answering this last part of your post.

Thanks, I'll give this a go. I was hoping to get this LED into the MK grid module ( Which I'd bought to do the job before realising the lack of neutral) but I think that may prove impossible. I'm wondering how neatly the led can be installed into part of the switch backplate, has anyone else done this before?

 

[marconi]

Colin33 - did you have a successful conclusion to this problem please?

(Sorry to nag because you are no doubt busy but the EF love to know the outcome of threads after advice is offered otherwise it is all theory - and we are practical people who want to know what works or not).

 

[Colin33]

Colin33 - did you have a successful conclusion to this problem please?

(Sorry to nag because you are no doubt busy but the EF love to know the outcome of threads after advice is offered otherwise it is all theory - and we are practical people who want to know what works or not).

Hi marconi, the client has been away so I've only recently been able to discuss the options with him. He has decided to leave things as they are for now, and hopes that the new brighter LED lamps I've put in his outside lights will make it more obvious if/when they are inadvertently left on. I'm rather disappointed because I was looking forward to experimenting with the current sensor!
I thank you and everyone else for the valuable input

 

[integrationdan]

Using a CPC for anything other than it’s intended use is not allowed on BS7671, you could look at using a LED wired in series in your circuit.

Wrong - do people think that a piece of conductive material with green/yellow indicator sleeving works differently in any way than the other conductors?

It is a metal, the colour is only an indicator put there by the manufacturer for our convenience. If you then decide to place brown/blue/grey sleeving atop of the green/yellow, what possible difference does it make.

Earth core has not been bestowed with some magical curse, it is simple copper with a coloured cover. No decent Engineer would ever consider it any other way. The only consideration might be the reduced C.S.A. if it's PVC/PVC flat twin and skin.

In fact if you wanted to use g/y as line, blue as CPC and brown as neutral - with a good reason, there is nothing stopping you. The regs only state they should be clearly identified at access points and terminations. This could be the word LIVE, letter L, the word LINE, or a coloured section of sleeving.

AND... the regs are a guide, used to supplement/inform. We as qualified Engineers can deviate any way we choose, as long as it is safe, and justifiable.

Danny

 

[littlespark]

Wrong - do people think that a piece of conductive material with green/yellow indicator sleeving works differently in any way than the other conductors?

It is a metal, the colour is only an indicator put there by the manufacturer for our convenience. If you then decide to place brown/blue/grey sleeving atop of the green/yellow, what possible difference does it make.

Earth core has not been bestowed with some magical curse, it is simple copper with a coloured cover. No decent Engineer would ever consider it any other way. The only consideration might be the reduced C.S.A. if it's PVC/PVC flat twin and skin.

In fact if you wanted to use g/y as line, blue as CPC and brown as neutral - with a good reason, there is nothing stopping you. The regs only state they should be clearly identified at access points and terminations. This could be the word LIVE, letter L, the word LINE, or a coloured section of sleeving.

AND... the regs are a guide, used to supplement/inform. We as qualified Engineers can deviate any way we choose, as long as it is safe, and justifiable.

Danny

Every cable must have a cpc in it.

Over sleeving the g/y to use it as a live conductor removes it as a cpc, and that cable no longer has one.
It doesn’t matter how short that cable is.

 

[DPG]

Wrong - do people think that a piece of conductive material with green/yellow indicator sleeving works differently in any way than the other conductors?

It is a metal, the colour is only an indicator put there by the manufacturer for our convenience. If you then decide to place brown/blue/grey sleeving atop of the green/yellow, what possible difference does it make.

Earth core has not been bestowed with some magical curse, it is simple copper with a coloured cover. No decent Engineer would ever consider it any other way. The only consideration might be the reduced C.S.A. if it's PVC/PVC flat twin and skin.

In fact if you wanted to use g/y as line, blue as CPC and brown as neutral - with a good reason, there is nothing stopping you. The regs only state they should be clearly identified at access points and terminations. This could be the word LIVE, letter L, the word LINE, or a coloured section of sleeving.

AND... the regs are a guide, used to supplement/inform. We as qualified Engineers can deviate any way we choose, as long as it is safe, and justifiable.

Danny

I think we're all well aware of the electrical properties of copper, regardless of the plastic covering it has. The issue is the identification, especially if the little bit of brown sleeving falls of at some point and someone assumes the grn/yellow wire is safe to touch.

The regs offer safe guidance in this case.

 

[loz2754]

Every cable must have a cpc in it.

Over sleeving the g/y to use it as a live conductor removes it as a cpc, and that cable no longer has one.
It doesn’t matter how short that cable is.

Every final circuit must have a CPC, but it doesn't necessarily mean every cable has to.

 

[davesparks]

Every cable must have a cpc in it.

Not quite, every point of termination must have a CPC at it, not every cable.

 

[Markyd]

Wrong - do people think that a piece of conductive material with green/yellow indicator sleeving works differently in any way than the other conductors?

It is a metal, the colour is only an indicator put there by the manufacturer for our convenience. If you then decide to place brown/blue/grey sleeving atop of the green/yellow, what possible difference does it make.

Earth core has not been bestowed with some magical curse, it is simple copper with a coloured cover. No decent Engineer would ever consider it any other way. The only consideration might be the reduced C.S.A. if it's PVC/PVC flat twin and skin.

In fact if you wanted to use g/y as line, blue as CPC and brown as neutral - with a good reason, there is nothing stopping you. The regs only state they should be clearly identified at access points and terminations. This could be the word LIVE, letter L, the word LINE, or a coloured section of sleeving.

AND... the regs are a guide, used to supplement/inform. We as qualified Engineers can deviate any way we choose, as long as it is safe, and justifiable.

Danny

Q1.53 Can a single-core cable having green-and-yellow insulation be used for any purpose other than a protective conductor?
No (with one specific exception). Single-core cables having green-and-yellow insulation must not be overmarked or otherwise identified, and must not be used for any purpose other than a protective conductor. The only exception is where such a cable is used as a PEN (combined protective and neutral) conductor, when blue markings must be provided at the terminations.
Regulation number(s):

• 514.4.2
• 514.4.3

 

[brianmoooore]

Neon indicator can be used to indicate a switch is 'off', of course, by connecting across the switch's contacts. Often used to show the position of a light switch in the dark.

 

[MJPD29]

Indeed it can, old thread but mk used to sell a neon indicator for light switches that connected across switch contacts. Haven't seen new ones for a long time but believe they are still available.