DE Metal Halides Dangerous?

[ChrisRD]

Hi All:

There's a thread going on over at ReefCentral where someone mentions a Giesemann Pendant going on fire. Another poster implied that he felt DE halides were more dangerous than other forms of lighting.

I was planning to give the Giesemann Pendant a try. Has anybody else heard of this? Are DE halides more dangerous than moguls? If so, why? That doesn't seem to make any sense to me... ...I thought all halides were equally dangerous

Thanks.

-C

 

[Len]

I couple of things I can think of that make DE bulbs a little more dangerous then single ended bulbs.
1. DE bulbs are usually secured with spring pins. This type of connection isn't as snug as a screw on mogul or medium base of singled ended bulbs.
2. DE bulbs burn hotter then SE bulbs. Needless to say, more heat = more danger.
3. DE bulbs have absolutely no shielding of UV. This has nothing to do with its reliability, but it's more dangerous for humans. You need to shield these bulbs. Riddle suggest outer envelopes of SE bulbs don't absorb all the UV, but they absorb a significant amount of it (at least down to "safe" levels). Any glass or plastic medium will attenuate at least ~40% of UV. DE bulbs, only go through one thin sleeve, while SE rays go through two (outer sleeve much thicker).

That might be other things to consider, but these came to me immediately. For clarification sake, I don't think there's a significant difference .... a properly designed DE setup (like Giesmanns!) should be as safe as a SE system. I'm interested in exactly what component set on fire ... perhaps electrical problems?

 

[Anonymous]

First I've heard of it. We've got Nova's running over our Liverock and while the Nova's get warm they aren't as warm as the units with the built in ballasts - however we will be starting our 120 with a System 230 Plus within the next week.

They get hot - but these fixtures aren't exactly new. They have been around for years in Germany. What many people here in the US don't seem to understand is that HID bulbs are designed NOT to be cooled. When you have a fan blowing on a bulb you actually screw it up a bit. The bulbs actually shift to lower color temps when running with fans on them.

As far as the internals go - I have had some of the pendants open looking at them and the wiring inside is extremely beefy - heavy guage wire with thick insulation so I have full confidence in them.

I would be curious to know what model caught on fire and why - none of that is mentioned in the post.

 

[Ritteri&Bubbles]

I second that, there could have been a number of reasons why the pendant caught on fire. I personally think that 1 single isolated case out of thousands of units built is negligible at best to be concerned about. I am sure there are many other cases of other fixtures going up in flames that are un documented. We are dealing with electricity here. And accidents do happen.

 

[Anonymous]

So how should you cool them without fans. I was thinking 2x 150DE bulbs but I do not run a chiller. I do not plan on getting one either. Would it make more sense for me to get 2x 175SE bulbs?

 

[MattM]

So how should you cool them without fans.

You don't.

As Tom mentioned, they are designed to run hot. Since they are in nearly sealed enclosures, all the heat is carried up by convection and almost none of it makes it into your tank.

 

[Anonymous]

Talked with Giesemann about this today - here's the scoop.

The fixture didn't catch fire.

What happened is that Giesemann is selling a TON of these fixtures in Japan. Japan uses 110 Volt electricity - so do we though in the US it can range from 110-120 (127?) while in Japan there it's basically 110 period.

Some of the 250W fixtures for the US market shipped with a transformer that was designed for the Japanese market but can't handle excursions into the higher voltage levels here in the US and the transformer burns/melts the plastic insulation of the wiring.

Giesemann is currently compiling a list of all the units shipped to the US with that transformer and will be shipping all owners of said units new transformers soon.

It's more of a nuissance than a safety hazard and if it's going to be a problem it's a problem rather quickly not something that takes a month to materialize.

Now if that new container will just get here from Germany, so I can have product to sell..... :roll:

 

[Jimmy Walls]

So they use a tranformer inside the fixture to convert our 110 to the lights 220.
Do all of their fixture do that?
Are of of them internal?
It sounded like the pendant had a external ballast, Does it have an external transformer.

Thanks,
Jimmy