Author Topic: Let there be light....  (Read 744 times)

Let there be light....
« on: January 08, 2020, 09:14:13 pm »
Many years ago my father installed false ceilings with halogen (?) spotlights into 2 bathrooms & a kitchen.  They've never been right with lamps dying on a regular basis.     Last weekend all the lamps in one of the bathrooms failed, so I've got to take a look at it  ???   


There was a standard light fitting in there before he put the ceiling up, so I'm guessing he ran everything off the power from that.   So, I'm thinking , turn power off, remove panels & find mains supply.  Disconnect from the lights & connect a standard bayonet socket & bulb.  Turn power back on & see if we have light.  If we do it's the lighting stuff (I think there is a transformer involved ?)  , if there is no light then it's another , messier problem.  Could be our little rodenty friends are back & nibbling stuff in the loftspace. 


If it is the lights what can I replace them with ?  Modern LED's such as https://www.diy.com/departments/brushed-chrome-effect-downlight/1701155_BQ.prd   ?    I believe the current ones use some type of circlip to hold them in place in the holes.  How would I connect them back to the original mains ?    Any recommendations for LED brands ?  Whatever I get they'll complain , they are the type of people who hoard incandescent bulbs to stick 2 fingers up to the EU  :facepalm:
Not fast & rarely furious

tweeting occasional in(s)anities as andrewxclark

hellymedic

  • Just do it!
Re: Let there be light....
« Reply #1 on: January 08, 2020, 09:23:54 pm »
Modern LED 'bulbs' are pretty good unless you're flicker sensitive and come with bayonet and ES caps.

I'd use the standard type unless there were good reasons to scorn them.

They are 3 for the price of 2 at Sainsbury's right now...

Kim

  • Timelord
Re: Let there be light....
« Reply #2 on: January 08, 2020, 09:51:04 pm »
If you're fitting halogen downlights in a bathroom (by the regs, just within some distance of the wet stuff, but who wants more than one style of fitting) you should use splash-proof (IP65?) fittings.  The normal ones are prone to catastrophic failure if water comes into contact with the hot glass.
Careful, Kim. Your sarcasm's showing...

Re: Let there be light....
« Reply #3 on: January 08, 2020, 10:31:07 pm »
I doubt if any regs were even considered when these were fitted.  The fire brigade would probably condemn the place.  That said, he did once wire up an entire house with exposed wiring (stone walls & wooden beams) and Manweb signed it off as OK. 


If it was up to me I'd take the horrible tacky false ceiling down, but that would mean removing all the wooden battens he screwed to the original ceiling & probably getting it replastered.
Not fast & rarely furious

tweeting occasional in(s)anities as andrewxclark

Kim

  • Timelord
Re: Let there be light....
« Reply #4 on: January 08, 2020, 10:48:57 pm »
As regulations go, that's one of the more sensible ones.  Nobody likes a dropped shower head ending with a BANG!, darkness and an unseen tinkle of broken glass.
Careful, Kim. Your sarcasm's showing...

Re: Let there be light....
« Reply #5 on: January 08, 2020, 10:49:29 pm »
Halogen lights come in two flavours: 12 V (which have little spikes on the back) and mains (which have mushrooms). If there’s a transformerry thing they’ll be 12 V.

Compatibility between LED lights and 12 V transformers is really unpredictable, so if you have those it’s best to rip out the transformer and go straight to mains powered LED bulbs, which will need new fittings.

Kim

  • Timelord
Re: Let there be light....
« Reply #6 on: January 08, 2020, 10:53:28 pm »
Compatibility between LED lights and 12 V transformers is really unpredictable, so if you have those it’s best to rip out the transformer and go straight to mains powered LED bulbs, which will need new fittings.

At which point you have the choice between generic mains downlight fixtures fitted with drop-in replacement LED lamps, or dedicated LED fixtures.  The former are naff, but when the life of the latter turns out to be about $warranty_period + 6 months, you avoid having to come back and replace them all.
Careful, Kim. Your sarcasm's showing...

Re: Let there be light....
« Reply #7 on: January 09, 2020, 12:59:42 am »
Compatibility between LED lights and 12 V transformers is really unpredictable, so if you have those it’s best to rip out the transformer and go straight to mains powered LED bulbs, which will need new fittings.

At which point you have the choice between generic mains downlight fixtures fitted with drop-in replacement LED lamps, or dedicated LED fixtures.  The former are naff, but when the life of the latter turns out to be about $warranty_period + 6 months, you avoid having to come back and replace them all.

IIRC the 12V transformers often used as halogen lamp supplies often produced very ripply AC.  I would imagine that adding a rectifier and a smoothing capacitor/regulator wouldn't be that difficult, and (bearing in mind the lower power consumption of LEDs) the rating of these parts needn't be that high. It might stop you from running halogens again though.

cheers

Re: Let there be light....
« Reply #8 on: January 09, 2020, 11:45:13 am »
Mains voltage LED in IP65 fittings, as Kim says. These use a tight fitting push (and sometimes twist) lens part that goes over the ceiling mounted bulb holding part.  I tried, and failed, to find an IP65 fitting with a screw-on lens part.  Problem with the push/pull type is, IF a bulb blows (ours were originally halogen, we were down to 2 from 6!)) the force required to remove the cover rocks the fitting in the (generally) plasterboard ceiling and loosens it slightly. Shouldn't be a problem if you use decent quality LED G10's, I used Philips.
We are making a New World (Paul Nash, 1918)

Re: Let there be light....
« Reply #9 on: January 10, 2020, 10:40:00 am »
If replacing the fittings, make sure the replacement ones also have a suitable fire rating (30 mins?)
The proliferation of spotlights in modern homes creates potential pathways for smoke/flame between floors if not suitably rated. You can get round this with intumescent fire hoods but these limit heat dissipation from the light.
Consider also the total depth of the ceiling void and manufacturers requirements for clearance. Some of the spotlight fittings won’t fit or won’t give adequate clearance in shallower roof voids.

Mr Larrington

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Re: Let there be light....
« Reply #10 on: January 10, 2020, 01:24:46 pm »
Modern LED 'bulbs' are pretty good unless you're flicker sensitive and come with bayonet and ES caps.

I'd use the standard type unless there were good reasons to scorn them.

They are 3 for the price of 2 at Sainsbury's right now...

Ta, Helly.  Bought a bunch yesterday.  Time to see whether they last better than the CFL ones in the timer-controlled standard lamp in the Great Hall.
External Transparent Wall Inspection Operative & Mayor of Mortagne-au-Perche
Satisfying the Bloodlust of the Masses in Peacetime

Kim

  • Timelord
Re: Let there be light....
« Reply #11 on: January 10, 2020, 01:24:52 pm »
If replacing the fittings, make sure the replacement ones also have a suitable fire rating (30 mins?)

Is that relevant if it's in a false ceiling?
Careful, Kim. Your sarcasm's showing...

Re: Let there be light....
« Reply #12 on: January 10, 2020, 01:56:25 pm »
If replacing the fittings, make sure the replacement ones also have a suitable fire rating (30 mins?)

Is that relevant if it's in a false ceiling?

I'd say not (and in a domestic situation I really wouldn't think it was an issue anyway) and also there's no heat dissipation problem with LEDS, as there was with Halogens.
We are making a New World (Paul Nash, 1918)

Re: Let there be light....
« Reply #13 on: January 10, 2020, 02:12:17 pm »
I've not been able to get a look at it yet, as I'm lurgified & don't want to pass it on to ageing parents.     I asked for a picture of the bulbs they've been using & was sent one of a GU10 LED , so don't know if transformers are involved at all.
Not fast & rarely furious

tweeting occasional in(s)anities as andrewxclark

Re: Let there be light....
« Reply #14 on: January 10, 2020, 02:20:45 pm »
I'd say not (and in a domestic situation I really wouldn't think it was an issue anyway)
Quote

If there's another flat above then the ceiling is meant to be a fireproof barrier. I can imagine a situation where a false ceiling was installed to add fireproofness.

(although it doesn't sound like that applies here)

Quote
and also there's no heat dissipation problem with LEDS, as there was with Halogens.

LEDs still kick out a fair bit of heat, and they're damaged by heat at much lower temperatures than halogens, so heat being trapped around an LED is worse, if anything.