lamp life

[carambola]

i have been having a problem with a particular type of lamp, 50w R20, either burning or blowing out. full relamping (27 cans - juno 4") 2 weeks ago and now 16 are burned out.
i have actual separation of glass to metal on two. none of these are under living space. any ideas or recommendations? 3 separate circuits same panel.

[iwire]

Did you happen to check the supply voltage?

[hillbilly]

Did you check voltage?

A loose or corroded grounded conductor can cause this.

Since it's occuring on 3 seperate circuits, I would check the service ground connection in the breaker panel, and also at the meter base and weather head (POCO).

Of course, it could just be a bad batch of bulbs...say that 3 times really fast:smile:.

Just a idea
steve

[carambola]

voltage is 123 and the egc is brand new.

[charlietuna]

Are all the lamps from the same supply house??? We once had a similar problem and found the lamps had a "virus" !! Thats what the final find was! Original supplier provided new lamps that burned out within days again -- lamp manufacturer sent us new lamps from the factory and solved the problem??????????

[carambola]

as a matter of fact these are all the same brand (sylvania) and from the same supply house.

[jim dungar]

as a matter of fact these are all the same brand (sylvania) and from the same supply house.
If the manufacturing line had a problem (i.e. defective cement to hold the glass to the base) then it is likely that the entire shipment to the distributor was affected.

[charlietuna]

On another job we had a large number of PAR38 Mercury lamps which cost around $40.00 a pop ! And they too were found to be deffective. Seems like there were about 80 of them along a entrance median which were all energized the same day and within a week 27 of them failed! Of course the manufacturer blamed everything on the installation and had us jumping thru our butts to monitor voltage-etc-etc.. This happened to be GE ! This case was blamed on a virus in the lamp's gas...

[Jljohnson]

I'm not a fan of the R-20 lamps from any manufacturer. I have hd better luck usung the PAR20 lamps, 130 volt rated on our new installs. The intrioduction of a dimmer into the circuit will greatly extend lamp life as well but I'm sure you already knew that.

[Rad sparky]

Check to see if the trim is rated for the 50 watt R20. I ran into that with wall washers once.

[LarryFine]

Of course, it could just be a bad batch of bulbs...say that 3 times really fast:smile:.That that that! :grin:

[bikeindy]

as a matter of fact these are all the same brand (sylvania) and from the same supply house.

I have had so many problems with Sylvania lamps I stopped buying them all together. I once opened a case of 60w standard incandecent lamps and I was trying to screw the lamp in and I tried and tried. For the life of me I didn't know why I was having so much trouble they wouldn't go in after about 3 minutes I took a careful look, and all the lamps were threaded left handed. Now how does this happen? best I can guess is that the threaded part was loaded into the machine upside down during production. I took them back to the supply house and the counter guy thought I was nuts. I pulled out a $100 bill and told him if he could screw it into a socket the money was his. Turned out they had a whole pallet of bad lamps. I could tell more stories about Sylvania lamps but I will never have any new ones I just refuse to use them. I am no fan of GE lamps either.

[LarryFine]

. . . all the lamps were threaded left handed. Now how does this happen? best I can guess is that the threaded part was loaded into the machine upside down during production.
That wouldn't do it; just like a nut on a bolt, flip it over and it still works. There's no way to left-hand threads accidentally.

That must have been a special order that got re-rounted. Why left-hand threads? I've read that it makes them useles to bulb thieves.

Really.

[MF Dagger]

I heard that too. That they use them on temp lights in nyc to keep people from stealing them.

[Rampage_Rick]

Left hand thread? Wow, learned something new...

http://www.globalspec.com/Newsletter/ViewPastIssue?issue=Vol3Issue20.html#Challenge

Think of the practical jokes that could sprout from such an item...