Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Please verify that my diy pendant light won't burn the house down

Status
Not open for further replies.

Deeg

Member
Hello all,

I have built my own pendant light and I'd like some expert opinions that I've done everything right. Full pictures of the project **broken link removed** but the following are the specifics:
  • There are 5 of these phenolic candelabra sockets.
  • Lamp wire is 18/2 SVT.
  • Light bulbs are 4x40- and 1x60-watt silvered crown candelabra.
  • Sockets are wired in parallel using push-in connectors. I only had 4-hole connectors so I had to use a total of 4 connectors to get it all wired. **broken link removed**.
  • Connection to power wires is with standard twist caps. Power wires are solid-core while 18/2 wire is stranded.
  • Care was taken to wire hot-to-hot and neutral-to-neutral.
  • Box in the ceiling is standard metal box with ground wire.
  • Total weight of the light is ~8 lbs.
I'm pretty confident that I wired everything correctly. The only nagging issue is that when the light was first turned on it started to smell after ~30 minutes; after a while the smell seemed to go away. I re-checked all the wiring and didn't see any problems whatsoever. My theory is that the sockets were getting heated up for the first time, getting baked, and the plastic was emitting the smell. Does that sound reasonable? Is there anything else I should check?

Let me know if you want any more info. Thanks!
 
I have three comments:

1. 60 W may or may not be too much. It would be great if you could add some holes in the class above the bulbs. Measuring the temperature of the lamp sockets would be a good thing to do. Ceramic sockets could be an upgrade. 60W per enclosed fixture is about the norm. Your fixtures are not enclosed, but the heat will concentrate above the bulb. The problem would go away with LED lighting.

2. Wiring should probably be done with "fixture wire". TFFN, for instance. **broken link removed** PVC isn't appropriate.

3. There should always be a separate wire to the ground, You are not allowed in the US anyway to relay on a fixing screw to make the ground connection (there are exceptions). So, you need a ground pigtail attached to the plate.
 
OK, a few comments:

There are no power ratings given for the lamp holders, so we do no know if the power ratings are being exceeded.

You have a total of 300 watts, I hope the switch to turn it all on/off is sufficiently rated.

The inverted cups and teapot have no ventilation holes to allow a through flow of air.
This will result in high temperatures within the cups and teapot and so the phenolic lampholders will start to smell.

Overheated phenolic does not last very long.

I cannot verify that you will not burn down your house.

JimB
 
Thanks guys, this is exactly what I need and I appreciate your time.

The sockets are rated at 75w. It sounds like most of the concerns can be addressed by using lower-wattage bulbs. If I swap out the 60w bulb for another 40w would that alleviate your concerns? If not, is there a wattage that would? I'll look into LEDs but I really like the look of the silver crown bulbs and prefer a solution that uses them. I'm willing to switch to ceramic sockets but I never found any that would work in this project.

I will add a ground wire specifically for the plate. Can I attach the ground pigtail to a small screw that is screwed into the plate? Is there a better way?

I don't know the rating of the wall switch; is there a way to determine it for sure (that doesn't involve replacing it)? The original light had 3 100w bulbs when I bought the place so I was assuming (yeah, I know) it could safely handle what I have.
 
Probably 75 W in free air.

You can probably put a very large ring terminal on the lamp threaded rod on the junction box side. If the rods were a bit longer, you could tap a screw in one and use a smaller terminal. Internal lock washers would help on the inside as well ans so would a little bit of Locktite 222 on the nuts.

Wall switches in the US will be rated at a minimum of 15A. Building wiring would be a minimum of 14 AWG (15 A) or 12 AWG (20A).
 
Thanks KISS. The medium (E-26) sockets are too big for what I want. I've scoured that site (and others) for candelabra sockets and the phenolic are the best fit for what I'm looking for.
 
The only thing I'd add to that is where the wire protrudes through the ceiling rose section there doesnt look to be any protection, what stops the wire from rubbing through on the metal?, I think maybe a good safety improvement would be to fit some 16mm cable glands at this point, or maybe just some grommets.
My wife wants one now.
 
My wife wants one now.
Nahh...
Just fire up the mercury arc rectifier and give her a suntan as well. :eek::eek:

JimB
 
The only thing I'd add to that is where the wire protrudes through the ceiling rose section there doesnt look to be any protection, what stops the wire from rubbing through on the metal?, I think maybe a good safety improvement would be to fit some 16mm cable glands at this point, or maybe just some grommets.
My wife wants one now.
I'm using these for strain relief on the wires: **broken link removed**
 
Just the job, well hidden on the pics.
Looks like you have taken every effort.
Its the thrown together couldnt care less ones I'd be concerned about.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top