Bad thermal protection switch in recessed fixture?

Reply

  #1  
Old 04-17-10, 09:17 PM
M
Member
Thread Starter
Join Date: Jun 2007
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Bad thermal protection switch in recessed fixture?

I have four recessed light fixtures in my living room. According to a label inside one of them, they are thermally protected and rated for up to 100-W bulbs. I used to have 60-W incandescent bulbs in them, but switched to 13-W compact fluorescent bulbs a few years ago to save electricity and reduce the frequency that I have to get out the ladder to replace the bulbs.

Recently, one of the four fixtures started shutting off (accompanied by an audible click) for about a minute and then coming back on. First, I thought the bulb was going bad, so I replaced it, but the problem persisted.

Then I investigated online and learned about the thermal protection feature that shuts the fixture off if it gets too hot. I also read about how overtightening bulbs can cause one of the contacts to get pushed far enough into the socket that it can no longer rebound and make a solid connection with the bulb. Lack of good contact can lead to arcing, which generates a lot of heat. I think this may have been happening because there is a small dimple on the tip of the bulb's socket. So I bent the contact up so it could make a better connection with the bulb. But the problem is still persisting.

I'm wondering two things:

1) Could the thermal protection switch be faulty? If so, would I have to replace the fixture? I am hoping to avoid that because I would have to tear up the ceiling (there is no attic space above it) and I would probably have to replace all four fixtures so they would match. And I would be surprised if the heat from a 13-W CFL bulb would cause overheating when the fixture used to be fine with a 60-W incandescent bulb.

2) Could it be that even after I bent the contact up, there is still a weak connection in the socket somewhere that is causing arcing? If so, I might try replacing just the socket (I've done that on another light before). I bought a new socket today (about $3 or $4 at Lowe's), but I'm hesitant to put it in because I'm not sure if a special kind of socket is needed for recessed fixtures because of the greater amount of heat that is typically present. I wanted a porcelain fixture, but they were sold out, so I got plastic instead.

I'm thinking I can manage replacing the socket by myself, but I would have to hire someone if I had to replace the fixture(s).

Any thoughts?
 
  #2  
Old 04-18-10, 12:49 AM
F
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,807
Received 0 Votes on 0 Posts
How long you have this recessed cans you have there ?


And did you do anything up in the attic like add more insuationg materals up there ?

Yeah from time to time the thermal switch can go bad but not too often it will happend.

What kind of trim ring you using on this cans like eyeball or open trim or airtite trim ? one of them will affect the performace on the can.

Merci,Marc
 
  #3  
Old 04-18-10, 08:54 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,765
Received 97 Votes on 87 Posts
Yes, thermal protectors can go bad, but it is rare. You would need the manufactuer's name and catalog number of the recessed can to get a replacement. These things are not generic, go back to the manufacturer to get a correct replacement. Like Marc was questioning, be sure the fixture isn't covered with insulation. If it is, the protector is just doing it's job. If that is the case, remove the lamp till you can solve the insulation over the fixture problem. Thermal protectors are mechanical devices and will eventually fail. If it should fail in the closed position, you have a serious fire hazard.
 
  #4  
Old 04-19-10, 09:50 PM
M
Member
Thread Starter
Join Date: Jun 2007
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Thanks for the thoughts so far. Here are some answers to your questions:

1) I don't know the exact age of the fixtures. I have been in the house for 5 years now, and they were there when I bought it. My guess is that they are original to the house, which was built in 1987.

2) No, I did not add any insulation above the fixtures. It would be impossible to do so because there is no attic space above them. There is about an inch of space between the ceiling sheetrock and the bottom surface of the roof.

3) The fixtures are square-shaped. They have metal square trim borders, which are connected to the fixture boxes by a couple of springs.

The lack of insulation above the fixture, combined with the fact that I'm using only a 13-W CFL bulb (well below the 100-W limit that is cited on a label inside the fixture), leads me wonder if there is a problem with a loose connection causing arcing in the socket. If that's the case, I'll just replace the socket.

That's another question I have--does the socket have to be a special, more heat-resistant type because of the greater amount of heat that can be present in a recessed fixture, or does any generic socket suffice? I have one of these from Lowe's: 70826 - Portfolio at Lowe's: Standard Base Socket. The socket's documentation is silent on whether the socket can be used in a recessed fixture.
 
  #5  
Old 04-19-10, 10:54 PM
F
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,807
Received 0 Votes on 0 Posts
The link you gave me to look it up about the bulb socket that is not usealy listed for recessed luminaires.

over 90% of indensecent socket in recessed luminarie they will use porclian { a very high tempture rated } to withstand the heat the socket you show us that may I just say may work but over the time the plastique shell will get brittle and crumple and cause fire.

The recessed luminaire you describing that is a horzontal bulb format and I have see them and they are pretty low profile units.

Now the other question it kinda give me a puzzle look is you descrbing the drywall and roof you say only a inch space so sound like you have semi flat roof there.

That will raise new question later but for now the key issue is get that luminaire working.

Stop by any lighting centre I am pretty sure they may have porclican socket on hand.

Merci,Marc
 
  #6  
Old 04-22-10, 08:46 PM
M
Member
Thread Starter
Join Date: Jun 2007
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Thanks again for the insight. I will get a porcelain socket to be safe, and I think I'll reuse the existing wires in the fixture instead of using the wires that might come with the socket. That way I can be sure the insulation for the wires is also appropriate for the fixture.

You are correct that the fixture is a horizontal-bulb format, and that it is low-profile. About the one-inch clearance--I realized I misspoke in my previous post. What I should have written is that there is one inch of clearance between the top of the fixture and the bottom surface of the roof. The key point here is that there's no attic space above the fixture, which means that (1) there's no insulation above it, and (2) I can't access the fixture from above if I decide to replace it. And I really don't want to tear up the ceiling.

I'll get a porcelain socket, replace the existing socket, and see if the problem goes away.
 
  #7  
Old 05-16-10, 12:31 AM
M
Member
Thread Starter
Join Date: Jun 2007
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Update: I successfully replaced the socket with a new porcelain socket. However, the fixture is still flickering out for short (30 seconds - 1 minute) times. I replaced the socket because I thought the old socket might have had a loose connection that was arcing, but the problem is persisting with the new socket.

What's next? Replacing the entire fixture? I'd rather not, as I would have to tear up the ceiling (no attic space above the fixture), but I can't have a fixture that flickers and may possibly be a fire hazard.
 
  #8  
Old 05-16-10, 06:12 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,765
Received 97 Votes on 87 Posts
Originally Posted by mp1980 View Post
Update: I successfully replaced the socket with a new porcelain socket. However, the fixture is still flickering out for short (30 seconds - 1 minute) times. I replaced the socket because I thought the old socket might have had a loose connection that was arcing, but the problem is persisting with the new socket.

What's next? Replacing the entire fixture? I'd rather not, as I would have to tear up the ceiling (no attic space above the fixture), but I can't have a fixture that flickers and may possibly be a fire hazard.
No, replace the thermal protector.

Yes, thermal protectors can go bad, but it is rare. You would need the manufactuer's name and catalog number of the recessed can to get a replacement. These things are not generic, go back to the manufacturer to get a correct replacement.
 
  #9  
Old 06-03-10, 10:05 PM
M
Member
Thread Starter
Join Date: Jun 2007
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Done. I replaced the thermal protection switch, and so far, the fixture is working properly. It hasn't tripped off yet.

The thermal protection switch looks like a little black stem (about 1.5 inches long) with three wires. I looked closely at the old switch, and saw that it has a hairline crack in it. I guess it just went bad due to age.

I couldn't just buy the switch, so I bought the chassis for a new fixture and used the new switch from it. It was about $13, which is a lot less than the cost of tearing up the ceiling to replace the entire fixture.

Thanks for the advice!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: