Surge protection for blown light bulbs?

[scott1ws]

Hi,

I've installed twelve pendant light fittings for a shop, using a mixture of ES & Bayonet 60/100W filament bulbs with dimmer switches turned low. The main lighting in the shop is with GU10 LED bulbs. The client has had constant issues with the filament bulbs blowing and has tried several different sources for bulbs, with the same result. The main info I have is ....

It's not consistent with a particular bulbholder.

It mainly seems to happen when the lights are turned on in the morning.

I have two thoughts, either to check the bublholders for signs of arcing, specifically the earth connections on the ES holders (even though it is not a particular holder causing the problem) or to monitor for voltage surges (which is a bit impractical) and fit a surge protection device on the board.

Has anyone had any previous experience of this situation, or can anyone give me any constructive advice?

Thanks.

 

[telectrix]

generally, filament lamps blow on switch on when the switching on coincides with the peak value of the supply sine wave. to get round this, use rotary dimmers so that they come on low on switch on, or replace with LEDs.

 

[scott1ws]

Cheers for the reply.

All the circuits with filament bulbs have been fitted with rotary dimmers in order to adjust the brightness, but are still controlled by a main master on/off switch that the staff use at night to switch the lights off before locking up. It is this switch they use in the morning to turn all the shop lights on with, so I could request they turn just the filament lights on with the rotary dimmers....

LED bulbs are not an option.

 

[Darkwood]

If you have just fitted these you are very short sighted as the 100w lamps are no longer been produced and 60watt will suffer the same fate too.... at some point in the very near future you are going to have to use low energy lighting regardless of whether its not an option, and with dimmers in series i can see a lot of problems coming your way.

 

[Deleted member 9648]

In my experience in the majority of cases it is poor lamps.....even well known branded filament lamps can be indifferent because of their fragility and the way they are handled/transported. Ever noticed how if you accidentally knock a filament lamp it goes extra bright and then fails soon after? They take a hundred knocks before getting anywhere near a lampholder.
Another possibility is that the lamps are not failing as regularly as the client says.....had this before and got the client to keep a written record of lamp failures, lo and behold....they were lasting much longer than he was originally saying.

 

[shagbite]

If you have just fitted these you are very short sighted as the 100w lamps are no longer been produced and 60watt will suffer the same fate too.... at some point in the very near future you are going to have to use low energy lighting regardless of whether its not an option, and with dimmers in series i can see a lot of problems coming your way.

i thought manufacturer's had found a loophole in the ban?? i read that the ban only extended to households, so the suppliers started making 'rough service' incandescent lightbulbs.

rough service = industrial.

i might be wrong, but i remember reading something along those lines.

 

[Darkwood]

Lamp life approx 1000hrs

8hrs a day 5 days a week =40hrs per week
25weeks life expectancy met or less than 6 months

If the lamps have a high switching duty this can dramatically reduce the lamp life and as above how the lamp got from the factory to you can also reflect on the lamp life.....expect on average 3months if used as above

 

[Marvo]

I have two thoughts, either to check the bublholders for signs of arcing, specifically the earth connections on the ES holders (even though it is not a particular holder causing the problem)

I don't understand why the earth connections would ever show signs of arcing, maybe you can elaborate on your thinking here?.

I've never seen an issue with GU10 lamp holders and ES holders are also very reliable so I doubt it's those. I'd check the L&N connections all the way through the circuit right back to the CU for tightness, also the main neutrals on the bars as well to start with.

 

[chrish_1977]

Testing would be a good start, just replacing parts won't cure the problem as you said you have tried different manufacturers and types etc, don't overlook the obvious problems as previous poster said before me, loose connections can kill lamps very quickly too

 

[Knobhead]

Marvo’s spotted it. Earth connection on an ES lamp?

Yet another chancer trying his luck.

 

[Marvo]

Wasn't sure if it was a case of fingers typing faster than the brain was thinking.

 

[scott1ws]

Wasn't sure if it was a case of fingers typing faster than the brain was thinking.

Yeah... spot on. For 'earth' substitute 'neutral'! I was in the office with a million other things going on in my head.

(My first post on this forum and I can be a bit stupid at times, but I'm a little disappointed about the 'chancer' comment. Not very helpful.)

My feeling on the circuit was that the weakest point was with the neutral connection inside the bulb holder. The neutral terminal on these holders is part of a spring connection that presses against the bulb making an outer contact. In my experience, on most standard domestic ES holders the inside thread is metal and makes a good tight contact when the bulb is fitted. On these particular holders the thread part is plastic and the connection is made with the spring connection at a particular point as the bulb is fully tightened. When I installed the holders I thought this spring connection appeared to be a weak point, and so I assume that if this connection was not tight there would be visible signs of excessive heat/arcing on the metal, due to a loose connection. This could increase chances of a filament bulb blowing?

The GU10 LED bulbs supply the main lighting for the shop and there have been no problems with these at all.

The filament bulbs (antique style squirrel/globe) are specific ones, available from various online UK retailers, that are being used purely for aesthetic/visual merchandising purposes, to draw attention of customers to certain areas of the shop floor, e.g over a table displaying shoes, shop window display, and the sales counter.

Thanks for all the advice.

 

[Knobhead]

Those lamp holders are as old as the hills. Used up to 500W that I know of. I doubt very much they are the cause of you’re problems.

I too have 1000’s of things on my mind, I try not to make mistakes.

 

[Darkwood]

The filament bulbs (antique style squirrel/globe) are specific ones, available from various online UK retailers, that are being used purely for aesthetic/visual merchandising purposes, to draw attention of customers to certain areas of the shop floor, e.g over a table displaying shoes, shop window display, and the sales counter.

Thanks for all the advice.

Check the estimated lamp life from manufacturer, candle, golf lamps etc have a shorter life span than standard lamps. Also make sure the lamp doesn't have to be fitted on a certain plain... some lamps require the bulb to be above the cap so fitting them with the cap above the bulb like in a pendant drop will see very short lamp life.

Test the set-up by popping in a few standard lamps in and i bet they last.

As for sourcing your product--- the internet ..well need i say more there is so much cheap and fake crap flying around the internet unless you are sure the are a large reputable company dont buy them.