Any electricians out there?

GloBug

Senior Flea Coller Tester
What is the difference between a shielded and a non-shielded halogen bulb? Yeah, bob, I know, the shield, but what IS that shield? And why does it increase the cost of the bulb x6?

My hood range takes shielded halogen bulbs, and they cost $30. We have the bulb at work, but it's not shielded, and it costs $5. I will still pay the difference for the shielded bulb, but what the heck is it and what does it do?
 

Cruizer

Staff Captain
Myth #4: Halogen is an ultraviolet radiation (UV) hazard.
False and true, mostly false. A standard incandescent lamp emits about 75 micro watts per lumen(µW/lm) of UV, and unshielded halogen emits 100- 200 µW/lm. (Compare this to daylight, which emits 300 - 600 µW/lm!) However Underwriters Laboratories now requires halogen lamps and/or fixtures to incorporate a glass shield that brings the UV emissions down to a negligible level. For example, an MR16 with a cover glass takes over 30 times as long to emit the same amount of UV as an MR16 without a cover glass.

Lighting Design Lab Articles - Halogen Heat and Hype

http://www.conexpoconagg.com/Documents/ShowDeadlines/LVCC_Halogen_Light_Policy.pdf

http://www.nema.org/gov/env_conscious_design/lamps/upload/LSD%201%20T-H%20Lamps%20v2_4%202003%20C6.pdf
 

GloBug

Senior Flea Coller Tester
I'm still confused. I found one of these sites on my own yesterday, and it appears that a shielded halogen has the glass across the lamp. But the ones that look alike, all have the glass across, and the prices are still from $5 to $30. I'm wondering if it's a special kind of glass???
 

Whimsy

Staff Captain
So, is it really necessary to buy the special one? I'm still confused.
 

GloBug

Senior Flea Coller Tester
Broan says that the halogen lights for my range hood are 120V, 50W, shielded halogen bulbs -- MR16 with GU10 base. I won't use one that isn't specified because I am sure there is a fire danger otherwise.

I just want to learn what creates the $25 difference in two halogens bulbs that look exactly alike.
 

suer182

Forum Manager
I will make some calls for you but I am going to ARSUME here........ even tho both bulbs look identical with a glass covering, the one that is shielded will have the yadada protective coating from the stuff halogens emit.

Think back to the touchier lamp days.

Light fixtures that use a conventional halogen lamp/light bulb will come with a 'sheilded'/protective cover over the bulb.

or it could be some protective coating because you are using it in a clock room appliance.

Either explanation, I could be talking out of my best feature.

Glo, does your range hood have a protective shield of sorts to be placed over the bulb? or just the normal decorative cover?

If I were in your shoes, I would go with the bulb/lamp that the manufacturer recommends.
 

GloBug

Senior Flea Coller Tester
Oh absolutely. I am not about to use the $5 bulbs, even though they look exactly the same, if I don't understand the difference. I am sure it's either a protective factor for me or the appliance.

There is no cover for the bulbs. This is a pic of the underside of my range hood. You can see the 4 halogen lights that are in the hood. The lights have the glass across them, and they do dim, so that might be part of the shielding factor too? I have no idea, and look forward to what you find out.

broan.jpg
 

Krazy Kruizers

Holland America Specialist
I have to agree -- you need to buy the more expansive light -- can't take any chances.

Interesting to rerad all this.
 

GloBug

Senior Flea Coller Tester
What's interesting is that every electrical person you asks has a different answer! Maybe I'll just email one of the electrical supplies on the net and see if anyone has a good explanation.
 


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