New Ceiling Light Fitting

[ollieldn]

Apologies for what i imagine is a very simple question:

I am replacing a working ceiling light with a new lamp which has a new fitting connected to it.

The electrical wiring of the flat is all fairly new (2013), and all of the lights are on dimmer switches.

The old fitting has 1 Earth, 1 Neutral, and 2 Live wires.

One live wire is connected to the ‘L’ marking while the other is connected to a central ‘Loop’ block.

Im guessing this has something to do with the dimmer switch?

The new fitting only has a standard 3 terminal block, L.E.N.

I covered up the ‘Loop’ live wire and connected the other wires to the new fitting.

All the lights work on all of the other switches, and the new one works but if I turn the dimmer switch down it begins to flash. In addition a hum/buzz eminates from the dimmer switch.

I have disconnected it again now, and am seeking your advice.

Thanks for the help

Ollie

(Can't post pictures as im new to the forum so it wont let me post links but let me know if that would help and i will try and find another way).

 

[NozSpark]

The new fitting doesn't have a...

Transformer

CFL lamp

LED lamp

by any chance???

 

[ProDave]

No it sounds okay as far as the wiring goes.

My guess is the new light fitting is not dinmable. I assume it's LED or CFL.  the instructions should say if it is dimmable or not.

Very unusual to only have 1 wire in the loop terminal.

 

[Doc Hudson]

The old fitting has 1 Earth, 1 Neutral, and 2 Live wires.

One live wire is connected to the ‘L’ marking while the other is connected to a central ‘Loop’ block.

Im guessing this has something to do with the dimmer switch?

How many cables are there, are they single core cables or multi core twin & earth cables. There aren't any other wires folded back tucked up above the ceiling are there. Dimmer switches need no wires than normal switches.

Doc H,

 

[ollieldn]

Thanks for your replies.


The new fitting is a standard lamp, E27 bulb fitting with a standard bulb attached.

Nothing to suggest that it is not dimmable.


There are deffinitiely only 4 wires, all coming from the same core flex.

 

[ProDave]

Thanks for your replies.

The new fitting is a standard lamp, E27 bulb fitting with a standard bulb attached.

Nothing to suggest that it is not dimmable.

There are deffinitiely only 4 wires, all coming from the same core flex.

That's very unusual.

Are they multi strand wires?  and what colours are they?

What type of E27 lamp have you got.  GLS (ordinary filament) ones were supposed to have been banned years ago. you can get them with Halogen lamps, CCFL lamps and LED lamps, not all are dimmable.

 

[Doc Hudson]

So its a three core + Earth cable.  (probably a left-over bit of cable someones used instead of twin & earth). What power rating is the new lamp and what rating was the old lamp. Traditional dimmers have a minimum and maximum wattage they can operate, e.g. 60w min 250watt max.  If you have a lower wattage lamp that could cause the light to flicker. Not all LEDs are dimmable and they also require a special lower power dimmer switch to work correctly.  (a lot of cheaper quality dimmer do buzz and hum when they are dimming!)

Doc H.

 

[ollieldn]

I had a GLS bulb lying around so that is attached at the moment.

I could try with a hologen lamps.

Hopefully this link might work:

unsee.      cc/pizaturo/

The old fitting had a normal bayonet B22 bulb fitted and didnt have the flickering or humming that i am observing now.

I am using an equivalent 40W E27 bulb in the new fitting so im guessing that the issues are being caused by the wiring/fitting

 

[Doc Hudson]

I am using an equivalent 40W E27 bulb in the new fitting so im guessing that the issues are being caused by the wiring/fitting

A 40watt lamp is most probably below the dimmers minimum power rating,  You would need to read on the back of the dimmer to confirm exactly. But 60w is a very common minimum rating.  You need a bigger lamp OR a dimmer with a lower Min rating.  

Doc H

 

[ollieldn]

Thanks Doc, I will try a higher wattage lamp and let you all know how i get one.

Thanks.

 

[Doc Hudson]

But also don't forget to double check the max allowable rating for the fitting. Some decorative fittings are only designed for lower wattage lamps. You don't want to put a bigger lamp in to get the dimmer working then find you damage the fitting with too big a lamp!

Doc H.

 

[ollieldn]

Understood!