Illuminated switch to show that cloakroom light and fan is still on

[Phil Addison]

Any suggestions for a source of illuminated light switch as a reminder that the light it feeds is still on? We have a loo under the stairs with the light switch on the outside and it sometimes gets left switched on so the fan remains running (as well as the light being on). I don't want to fit a clunky 20Amp DP mains switch like this

this I really want is a basic light switch like this with a neon indicator incorporated. I can't find such a thing, the nearest being this but it works the wrong way round - the illumination is 'on' when the switch is 'off' - its so you can find the switch in the dark. I suspect the wiring could be reversed, but as it's intended to show up in the dark it may not be bright enough for use in a lighted area.

I also found this

is an illuminated section that sits between the switch and the back-box. Again I'm not sure if its bright enough and it seems a bit of an overkill.

I'm considering modifying a standard light switch by drilling a hole into which a small neon or LED is fitted. There is some safety consideration here so wonder if there is suitable double insulated neon/led available. Failing that I think I need to create some kind or perspex window in the switch with the neon/led behind it.

Any thoughts?

Phil

[Steve Walker]

LEDs do not have insulation deemed suitable for mains, unless you have one with a surround and lens. The other problem is that you don't normally have a neutral available at a lightswitch, hence you can light a neon or LED easily enough when the switch is off (using the switched light as the path to neutral, as the current is too low to light it), but not when the switch is on.

SteveW

[Dave Plowman (News)]

Snag is light switches don't normally have a neutral available. The type which is on with the light off gets the neutral via the light - since it only takes a small current, the lightbulb looks like a short to it and thus provides the return. I suppose you could run a small neon to earth - since this is no worse than many SMPS do. But don't tell anyone I suggested this.

[chrisj.doran]

What the OP wants is a "panel neon", e.g.

or LED: check that they aren't too deep for the switch box.

However, I wonder whether a neon/LED will be prominent enough in daylight, or too easy to ignore even if it is.

If the door is visible down a corridor, you could just drill a hole, or even replace a whole panel with frosted glass, but again it may be difficult to see in daylight.

A third possibility is to replace the switch by a motion (sorry) detector as used for security lights.

A delayed-off time switch is another possibility, but would need to be inside so that it could be reactivated if things take longer than expected!

Chris

[dennis]

As long as the rcd, if present, doesn't trip.

[Dave Liquorice]

A PIR is a good solution. I had one in the kitchen of my old flat as I'd be for ever leaving the lights on (3 x 100W spots) and forgetting. Has the advantage that the light comes on automagically when you enter and if it does switch off you just wave to switch it back on.

An inital thought was a micro switch operated by the door, closed = off. But that isn't very convenient when the room is in use. I don't think a two way switching arrangement would solve that either.

[Phil Addison]

Thats the one! thank you! enclosed and fully mains rated. The box is

51mm deep from front of switch so the 29mm lamp will fit easily.

We walk past it often enough so I think the red neon will be fine.

I did have the switch inside originally, but of course its dark in there until you find where the switch is, so moved it outside, where it does seem more 'convenient' on the whole.

As others pointed out (thank you Steve, Dave) the neutral is absent, but I can run one in fairly easily, but am inclined to use the earth. IIRC the series resistor is usually of the order of 220K so only adds a milliamp to the leakage current. I can always add the neutral later if leakage is a problem. My CU is due for an upgrade anyway as it is currently the old fuse-box type.

Phil

[Tim S]

[e-mail] coughed up some electrons that declared:

I was going to suggest a grid switch panel (single gang, 2 grid modules), one 10AX switch and one grid indicator (amber, red or green). Those are all designed for easy wiring and of course 240V.

The problem remains as to where to get a neutral from. I'm not sure what current a grid neon takes (largely determined by the series resistor, but I wouldn't advocate linking it to earth.

B&Q sell the MK range of grid stuff including indicators, but GET do a nice range with pretty switches and nice panels if you need to match some existing scheme eg brass or white nickle etc.

Cheers

Tim

[auctions]

brands may be more suitable. Crabtree's DP switch is visually very similar to the light switch, so the neon version looks like a light switch with a neon just above the switch.

A

[dennis]

I used

so i had a light next to the switch in my shed. They are cheap, but as its been said before you need a neutral. I suppose it would be possible to retrofit a flashing led into a neon housing and run it on batteries for months at a time.

[NT]

Cnnected from L to E a neon on a 220k resistor will add in the region of 0.7mA. An ultrabright LED can be run off much less than 1mA with decent light output. And if you run it from a CR dropper the power diss would be even tinier. The LED would need a rectifier of course.

NT

[John Rumm]

You can get things like:

although designed for heavier loads are not particularly clunky in use. However, they suffer the usual limitation of requiring a neutral at the switch position to work.

[george (dicegeorge)]

Wouldnt this add to RCD trip current?

Why not wire it between L and N?

And how does the switchlite work?

glows when not switched on, but has no Neutral or Earth connection, is it like my neon mains testing screwdriver?

[g]

[Tim S]

george (dicegeorge) coughed up some electrons that declared:

No - that neon goes across the switch and uses the load as a relative neutral when switched off - which works well with a resistive load. Electronic loads, eg a CFL are a different story but if the current is low enough you may get away with it. In other cases you can get weird effects like the CFL flashing.

[Dave Plowman (News)]

It won't from a neon alone - they take near zero current. Otherwise neon screwdrivers would be a tad dangerous. IIRC, of the order of 1-2 mA. Less than many SMPS dump onto the earth.

[Dave Plowman (News)]

You just parallel a reverse connected diode to the LED for AC. Plus a suitable current limiting resistor, of course.

[Phil Addison]

I don't know this particular one, but the ones I have seen require quite a lot more pressure than a light switch rocker, and emit a resounding 'click' when operated. That's why I'm looking for an alternative. I'm off to maplin tomorrow for their red neon as posted by steve, so its going to be a DIY job!! Must say I was surpprised to find the big names don't make a SP lighting circuit varient of the 20A DP SW+neon.

Phil

[Phil Addison]

That's neat. That will bypasses the LED on the reverse cycle, and is probably easier to wire in than a series diode. It allows you to use a tiny low voltage diode whereas the series one needs to be a bigger mains rated 1N400x series. OTOH it draws twice the current of the series solution, but still a mA or so.

Doesn't the 1/2 wave rectification halve the brightness though? An electrolytic capacitor in parallel should solve that if it doesn't need too many uF's - haven't calculated the size.

Phil

[NT]

yes, but by very little

there's often no N present

NT

[NT]

you can, but the resulting flicker is terrible. Worth going for 100Hz flicker imho. That also gets you half the capacitor size.

NT