Any electricians out there?

GloBug

Senior Flea Coller Tester
#1
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

Well-Known Member
#4
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
#5
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???
 

GloBug

Senior Flea Coller Tester
#7
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
Staff member
#8
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
#9
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.

 

GloBug

Senior Flea Coller Tester
#11
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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