Irregular light fault pattern. Circuit issue?

[amos]

Hi all

I have just been wondering.

In the kitchen we have 4 lights off the lighting circuit. 2xmains halogen (4x500 each), 2x transformer to 20V halogen (3x20W each)

Prior to this we had one 4x100W incandescent unit, and 1x100W incadescent lamp.

The circuit, wiring etc is graded as suitable for these loads. We have an old style fuse box (yes I know it should be replaced :) ).

Now I have noticed the failure rates of both the incandescent (originally) and mains halogen (now) bulbs is much higher than I would expect compared with rest of house (yes I have taken into account the fact that with that many bulbs the rate of failure in some bulb is going to be higher, and yes I have tried - not so easy - to take into account the relative usage of different lights). I'd say kitchen bulbs last

1/3-1/2 as long as I would expect.

Also now 6 20W, 20V G4 halogen bulb fittings have suffered fitting burnout so that they do not make contact.

My working hypothesis is:

[The Natural Philosopher]

Mains halogens have a lifetime measured in minutes,not hours IME. replace with 12V if you must. Dio you really mean 4x500W?!!

I've never heard of 20V units.

I have great lifetimes of 12v halogens - 50W units. Especailly if run a little less than full brightness. All that takes is a longer piece of cooker cable between the transformer and the bulbs. Adds just enough Vdrop..

[Dave Plowman (News)]

Presumably 50 watt mains and 12v 20W?

Mains halogens - GU10 - can have a very poor life. I made the mistake of using these in my bathroom. The lamps supplied with the fittings all went in short order. The replacements - bought from TLC - have been ok. But I make sure to switch them off when not needed.

12v - M16 - are very much better. As well as more efficient.

Given the same fitting is used for 50 watt lights I'd say you've got poor quality ones.

Some may be. But not all.

Low voltage fed from the same transformer may have a shortened life if one blows and you don't quickly replace it.

Not that I can think of. If your voltage was higher than normal it would effect all lamps.

[John Rumm]

Not sure that makes sense. 4x500W would be ok if you use them in place of a cooker I suppose! 4 x 50W would seem more likely.

Never heard of 20V halogen lighting systems - Could you mean 12V?

Even including the 2kW of halogen? ;-)

Why?

Just because it is old does not necessarily mean there is a need to change it:

Now I have noticed the failure rates of both the incandescent

Replace the light switch. (we have had long and boring threads on this in the past, but suffice to say its cheap and worth doing in the circumstance)

Secondly, don't expect much life from some mains halogen lights (GU10 spots being the most vulnerable it seems) - especially if there is any vibration from say the room above.

Cheap and nasty fittings perhaps? Unlikely to be influenced by external factors unless the wiring to them is either undersized or poorly terminated and hence resulting in lots of local heating.

Again, assuming you mean 12V, no quite the contrary - LV halogen are far more robust than mains powered ones. Long lifetimes should be achievable.

Bulb lifetime effect is due to poor computation of expected lifetime on

What failure are you getting? Just filament failure, or bulb explosion?

[NT]

If you mean mains 50w, get rid of them, theyre terrible for bulb failures. If you mean 500w, go for the eye surgery.

no reason why, unless its proving a problem. New and old types both have their somewhat trivial safety issues.

junk fittings then

they shouldnt affect each other - but if you're using a toroidal transformer they will to a degree

youre right in that the issues that affect mains halos wont touch the LV ones

Indeed. Failures will continue, not because youre missing something, but because its one of the downsides of multiple halogen lighting.

Thanks in advance for any pearls of wisdom, or suitably disparaging > remarks :) >

This is a trick worth considering:

[John Rumm]

?title=Fluorescent_Lighting#Disguised_Supplemental_Lighting

[Mike Tomlinson]

In article , NT writes

I find they're OK if given room above for heat to dissipate, or if they are fitted in a surface mount fixture which has some way of ventilating the bulb.

[NT]

NT

[Amos]

Duh. Whoops. How did that happen. Yes. Two errors in one sentence. Note to self. Read post again before inflicting on others.

Yes - they do but they seem even worse than elsewhere. If I come across a suitable 12V unit I might replace sometime.

Thanks - the 12V bulbs are fine. Its just all the fittings have burned out.

Thanks. I guess I'll just run ahead and replace the faulty units then.

Amos

[Amos]

John Rumm wrote

Indeed. 12V. I agree LV halogen are much better. I meant My current 12V halogen fittings are bad...