[chesie]

We installed 9 well lights within a sidewalk 2 weeks ago. Since then we have gone through 12 bulbs. They are the PAR 36 style bulbs that have the stacon connectors. The bulbs keep blowing(commonly referred to as smoked). The volts at the fixtures are reading 11.3- 12.0v. Only 3 fixtures per run on 10 wire. Anybody have experience with this? I am stumped and the manufacturer has yet to come up with something.

I am pretty savy when it comes to electricity.....but this has me baffled.

[Bill Schwab]

Ok. You got 11-12v, what amperage is registering? I had a transformer once that spiked for whatever reason, voltage was fine. The amperage pumped up inside and wasted everything. Is there another transformer you could rob from somewhere and use on the line?

[chesie]

It is funny Bill...I knew you would be the first to reply. I was thinking along the amps as well but it appears my ampprobe is not properly calibarated. I was registering 0.8amps when I should be drawing 21.6.

I have an extra transformer and i will try to swap out and see if that hleps.

Thank you for the insight.

[nightscapespaul]

I had a problem with the GE 18 watt and 25 watt par 36 lamps for awhile. I even had a couple "smoke" as soon as I hooked them up. It turns out that I had gotten some bad lamps from an online source. I replaced the lamps with sylvania and have not had a problem since.

[chesie]

I finally got this problem worked out. I switched all the bulbs to 35watt and have not had a problem since. I will say that Cast did give me a case of free bulbs for my trouble, doesn't cover the time I lost but it was something.

[nightscapespaul]

That's it, you have to use the 35 watt lamps. After I switched, I haven't had a problem. I also have stopped using par fixtures because of this.

[chesie]

Well that was my conclusion after wasting many a man hour trouble shooting this....no more par bulbs.

[Inspired]

Ok, can you guys fill me in? What exactly was the issue and how was it fixed with 35w bulbs?

[nightscapespaul]

The problem seems to have been (this is my opinion) poor lamp design. The 18 and 25 watt GE par lamps were a major problem for me. GE no longer makes the 18 watt lamps. I hear that the 25 watt lamps are better now but I no longer use par fixtures. When I did switch to the 35 watt lamps, I stopped having any problems. Of course that meant that I had to redesign my lighting systems.

[Inspired]

As ar as the PAR36 stuff is concerned, you are right on. I haven't used one since like 97' or so. The lamp life is way shorter then an MR16 even if they burn normally. The old 4414 that use to come standard in Nightscaping well lights had like 400 hrs of life. I found out one day from a bulb supplier that they were actually bus signal light bulbs. No kidding. They have an interesting spread but the lamp life always weighs out for me. I'm surprised to hear Cast has a PAR36 fixture.

I thought you guys were talking about some other issue that increasing that wattage demand solved. I was definately curious.

[davidfarnham]

Hey Guys,
This is my first reply on this forum. Having been an old power co. electrical engineer, this subgect is interesting to me. I don't know if the bulbs discussed here are incandescent or not. If so, an overvoltage reduces the life of the bulb dramatically. I too have had some bulb failure recently & the manufacturer tech. said they do not recommend an incandescent We changed to Halogen & no longer have any problems. The 35watt bulbs mentioned are probably better made than the lower wattage bulbs.

[nightscapespaul]

All of the lamps that I have used have been halogen. I also run my lamps at about 11 volts. I have actually had 18 and 25 watt halogen par lamps blow in my hand while hooking them up!! When I went to 35 watt (which really screwed up my wiring and my transformer selection) I no longer had a problem. I figure that if I can only use 35 watt lamps in par fixtures, then I don't need to use them at all.

[davidfarnham]

After reading about the voltage some of you guys say you are running on your bulbs, I have a comment & a question. I design my circuits for max voltage drop at eack bulb of 5%. In most of the areas I work, the voltage delivered by the power co. is 125 volts, therefore 12.5 volts on the output of a lighting transformer. Thus, my design voltage with voltage drop to each bulb is 11.88 volts (12.5-.05*12.5=11.88). That brings me to my question. How do you guys figure voltage drop? I have found that some of the factory rep's info on the web on low voltage lighting calculations gives results that are exactly half the voltage drop. That tells me that that they don't even understand basic circuits or Ohms Law.