Let there be light....

[andrewc]

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 

[hellymedic]

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]

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.

[andrewc]

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.

[Kim]

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.

[grams]

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]

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.

[Brucey]

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

[rafletcher]

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.

[Quisling]

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]

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.

[Kim]

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?

[rafletcher]

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.

[andrewc]

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.

[grams]

I'd say not (and in a domestic situation I really wouldn't think it was an issue anyway)

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)

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.

[andrewc]

Thread Resurrection !     I finally summoned the 'tuits to look at this.  They've had a camping lantern in the bathroom for the last 3 1/2 years! 


I took 2 ceiling panels down yesterday.  Pictures of the mess can be seen here https://www.flickr.com/photos/andrewclark/ 


I found a DET 105 transformer.  My test pen showed current going in, but nothing coming out, so I assume this is knackered.





Question 1.  Are all DET 105's the same?  Can I just stick this in place of the existing one ?  https://www.diy.com/departments/osram-et-parrot-105w-electronic-transformers-for-low-voltage-halogen-lamps-220-240v/4008321111579_BQ.prd    (available from Amazon for £9.00)


Question 2.  Is it possible/sensible to replace the existing MR16 halogen lamps with MR16 base LEDs.  I assume I'd need a different type of transformer, so which type?  It's a smallish bathroom but there are 8 lamps to power.  Current bulbs are 20W.

[Mrs Pingu]

When we moved in here I replaced GU10 halogen bulbs with led bulbs without changing owt else so I assume you should be the same

[grams]

A lot of halogen drivers behave oddly with LED bulbs because they don’t provide enough load. You really need a specific LED rated one.

GU10 are (usually) mains rated so you’re getting an LED-compatible driver for free.

[andrewc]

A lot of the wiring is inaccessible without taking the rest of the ceiling down, and I don't want to do that.    Hence I want to retain the MR16 fittings.


Would the stuff below be suitable replacements ?


https://www.screwfix.com/p/lap-0301384031-gu5-3-mr16-led-light-bulb-210lm-2w-5-pack/739pp


and  https://www.amazon.co.uk/DUSKTEC-Transformer-Voltage-Constant-Lighting/dp/B09WR323PJ/ref=sr_1_6

[Kim]

Sounds like it ought to work.

Check the state of your MR16 connectors (often these are separate to the lamp holders themselves, and easily replacable).  When used with tungsten lamps the combination of poor contact, high current and thermal cycling means they tend to end up full of carbon deposits from arcing, so I wouldn't be surprised if some of them are knackered.

[andrewc]

Well, I replaced all the bulbs with 2W LEDs and replaced the transformer with the unit above.  4 of the 8 lights now work.  The other 4, on the other side of the room don’t.  My current detector pen shows that power is getting to them though.


Is there likely to be another transformer that needs to be replaced?  Apparently that side of the room failed before the other.

[andrewc]

And yes, there was another transformer.  I can’t work out how he got it through that hole into the void above the ceiling.  I couldn’t get it out, so just disconnected it & replaced it with the new one.  Now I’ve just got to get the awful tongue & groove PVC panels back up.