What are these halogen bulbs from a traffic light?

December 3, 2013 8:16 AM

I have a UK traffic light head with 3 halogen bulbs (12V AC). The bulbs it came with are just like G4 12V halogen bulbs, except that the legs are fractionally thicker. It seems like they are not G4 bulbs -- so what are they?

When I buy new G4 bulbs, they don't fit well in the original bulb sockets; they are loose (but they do fit, and they do work).

I have replaced one of the bulb sockets with a new G4 socket fitting, as the original fitting burnt out. Now the original bulbs won't fit into my new G4 spec socket, as their legs are too thick.

So what bulb spec are these bulbs, which look identical to a G4 to my eyes, but have ever so slightly thicker legs?

posted by richb to Technology (5 answers total)

I have a traffic light head of my own. Unfortunately, the bulbs that they use tend to comply with different standards than residential or even commercial lighting. The only place I was able to find replacements was some kind of municipal supply outfit, and they weren't cheap.

Without getting an actual look at the thing it's going to be impossible for us to tell. Here's my suggestion. See if you can identify the manufacturer and model number. If you can do that, hit up the googles. The manufacturer's website will likely have the product info you're looking for. From there, you should be able to identify the right bulbs and find someone to sell them to you.

Alternate suggestion? Contact your local public works office. They probably won't sell you a bulb--they won't have a procedure for that, and bureaucrats without procedures are fish out of water--but you might find someone willing to hook you up with the right info, particularly if you came by the thing legally.
posted by valkyryn at 8:28 AM on December 3, 2013 [1 favorite]

Best answer: Sounds like it could be a GU4 or GZ4 base. They have 1.0mm legs instead of the G4's 0.7mm legs. Aside from some iffy hits on Alibaba, I can only find that base on bulbs with integrated reflectors. Would one of those work?
posted by zsazsa at 9:38 AM on December 3, 2013

Best answer: A GU4 is the normal leg size in the UK, as far as I know.
posted by ambrosen at 12:30 PM on December 3, 2013

My apologies. Obviously you're talking about capsule bulbs, not ones with integrated reflectors.
posted by ambrosen at 12:32 PM on December 3, 2013

Response by poster: Thanks for your help, that looks exactly right.
Now where can I buy some GU4 / GZ4 capsule halogen bulbs?

Amazon seems to sell a few GU4 spots, but all their capsules are G4.

I need something like this but with GU4 / GZ4 legs. I haven't found any yet...
posted by richb at 5:58 AM on December 4, 2013