Switch off but bulbs on(ish) puzzle

I've just replaced 5 33W G9 halogen bulbs in a light fitting with 1W G9 LED bulbs.
As I swapped the bulbs one by one all seemed normal until I unplugged the last halogen at which point the other four LEDs started glowing dimly. Replacing the halogen bulb turned the LEDs off again.
Now with all five bulbs in they all continue to glow dimly when "off" and work normally when on.
How do I fix this? It's a one-way switch that only controls one light. It is next to a two-way one that controls the upstairs hall light.
(I've just replaced all the halogens with LEDs in the upstairs hall light but it doesn't display this phenomenon.)
Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tim+ wrote:

Some do, some don't. Discussed regularly in this NG Nothing you can realistically do about it. It won't be consuming a measurable amount of power.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 14:24, Tim+ wrote:

It will be a case of inductive coupling - when "off" the switched live is left floating - its obviously getting enough voltage induced in it to pass a very small current through the LEDs SMPSUs.
You need a small load near the lamp fitting to "pull down" the switched live when off. IIRC TLC had a suitable widget, but I can't recall what they called it to search their site. (a high value resistor, or even suitably selected capacitor would probably add enough load to discharge the floating wire)
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks. I don't mind living with it to be honest. I was more concerned that it might have indicated a wiring fault.
Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wednesday, 2 December 2015 17:10:11 UTC, Tim wrote:

due to wiring capacitance. Can be reduced or stopped by adding a capacitor L-N after the switch. Use a class X cap though, and add a s,all series R with the cap.
NT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This
https://www.tlc-direct.co.uk/Products/SMFLA01.html
I once did say what was in them but cannot remember what. A similar part from RS is about £2.
--
Adam


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wednesday, 2 December 2015 18:42:40 UTC, ARW wrote:

9

the

and

It

is

ass





A snubber is way cheaper!
NT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Have your measured the voltage between earth and neutral
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Have your measured the voltage between earth and neutral
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 14:24, Tim+ wrote:

Induction. If you want to stop it, replace the on/off switch with a change-over switch with Common connected to the lamps and NO and NC to live and neutral respectively. Then, in the 'off' position, both sides of the lamps will be connected to neutral rather than having one side floating. Careful how you document it, though, for anyone who may follow you!
--
Cheers,
Roger
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

By changeover switch do you mean a 2 way switch?
--
Adam


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 18:40, ARW wrote:

Yes - one with 3 contacts, with either NO or NC being connected to COM. I guess that's what a 2-way switch is(!) but I didn't call it that because it wouldn't actually be used for conventional 2-way switching in this application.
--
Cheers,
Roger
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 19:20, Roger Mills wrote:

You had better ensure its a break before make switch with plenty of contact clearance.
Adams ready made filter is a better bet.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


Bloody hell Den. You beat me to it. Same words:-)
--
Adam


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 19:49, dennis@home wrote:

Your main problem is likely to be a lack of neutral available at the switch position in the first place...
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Could it not be connected at the light fitting or ceiling rosette?
Richard
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2015 22:28, Tricky Dicky wrote:

If you replace the switch cable between rose and switch with a 3&E, then yes you could use a 2 way switch. Some kind of pull down is still going to be a lot less hassle though.
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


It would have to be a specific change over switch. A normal 2 way light switch cannot be used as a changeover switch in the way you suggest. A change over switch needs a "break before make" contact.
What often happens in your suggestion is that when the switch is operated there is a small short of the NO and NC connection to COM as the terminals are not designed to take such switching. This is something I have seen at work several times. It works on paper but not in practice.
As an aside, the OP may not have a neutral at the back of light switch! Some of us can still manage to wire a lighting circuit without a neutral at a lightswitch:-)
Cheers
--
Adam


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wednesday, 2 December 2015 19:55:13 UTC, ARW wrote:

A double pole switch would fix the problem and be legit too. But wiring would need altering.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 03/12/2015 08:02, harry wrote:

If you wanted to avoid wiring changes then using a miniature SPST mains relay at the ceiling rose, with the coil across switched live and neutral, and the main contacts between neutral and the lamp holder neutral, you would achieve the same effect - i.e. disconnecting the neutral from the lamp when the switched live is removed and the relay de-energised.
(and to keep it really simple, you could probably skip wiring the neutral through the relay - the load of the coil would likely stop the glowing anyway ;-)
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.