Okay To Keep Old Knob And Tube Light Fixtures - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-31-2010, 04:42 PM   #1
Member
 
Join Date: Dec 2008
Location: Western Arkansas
Posts: 323
Rewards Points: 250
Default

okay to keep old knob and tube light fixtures


I'm replacing k&t wiring with NM. I would like to keep some original ceiling fixtures. The possible problem is that the old wiring ran through a hole in the plaster ceiling and into the fixture. No box and no metal top to the simple fixture itself. The fixtures are decorative metal open at the top with decorative globes on the bottom.. The electrical part is a ceramic insulated socket and is held in the fixture by means of a threaded ceramic part kind of like a nut that screws onto the socket which extends through the fixture, trapping the fixture between the halves of the ceramic part. The wires mount under screws an inch of so below the level of the ceiling when it's all together. I could mount a box but wonder about the following possibility. I can cut a metal disc that fits snugly into the top of the fixture and would end up about 1/4 inch below the ceiling when the fixture is installed. That would totally enclose the electrical connections. It would need a couple of clearance holes to allow the original fixture mounting screws to go back into the framing and a hole in the middle for a cable clamp. Is that acceptable code wise? I have access to the equipment to easily make the metal disc which would be easier than cutting the fragile plaster/lathe and fitting a box.

Advertisement

Mike in Arkansas is offline   Reply With Quote
Old 01-31-2010, 05:25 PM   #2
Member
 
Join Date: Jan 2010
Location: Saskatoon Sk. Canada
Posts: 423
Rewards Points: 258
Default

okay to keep old knob and tube light fixtures


Some of those fixtures are real nice to look at and would be nice to keep.However the wire in them is probably rubber and/or fabric coated and quite brittle from age.You might feel more comfortable in the long run to replace the wiring in the fixture as well as the sockets. I doubt if a home made box would be acceptable to code.There is a box available, often called a saucer box. It is about 1/2 inch deep and in my area is allowed a max of 1cable with 2 wires plus ground. It is surface mounted and is usually used for exterior lights beside doors.

Advertisement


Last edited by daveb1; 01-31-2010 at 05:44 PM.
daveb1 is offline   Reply With Quote
Old 01-31-2010, 06:04 PM   #3
Member
 
Join Date: Dec 2008
Location: Western Arkansas
Posts: 323
Rewards Points: 250
Default

okay to keep old knob and tube light fixtures


Thanks Dave. I am replacing all the old wiring so no problem there. I thought about trying the saucer or pancake boxes but even at 1/2 inch it won't go into the fixture. Seems like what I want to do would essentially be a zero height box. You may be right though it likely won't meet code for one reason or another. Maybe someone else will give their opinion.
Mike in Arkansas is offline   Reply With Quote
Old 01-31-2010, 06:27 PM   #4
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

okay to keep old knob and tube light fixtures


Do you have pic of the fixture where the wires enter ?
Scuba_Dave is offline   Reply With Quote
Old 01-31-2010, 08:16 PM   #5
Member
 
Join Date: Sep 2008
Location: Oregon
Posts: 1,497
Rewards Points: 500
Default

okay to keep old knob and tube light fixtures


FYI - A new fixture install would have an electrical box to enclose the electrical connections. Electrical connections come loose and sparks fly. The wires can get to be quite hot with a loose connection. Best to contain these sparks and hot (temperature) electrical wires in an electrical box.

The wire used is rated for a high temperature. The heat from a bulb gets to be quite hot and can wreck wiring, then the insulation falls off. (I've seen wrecked insulation even behind wall mount fixtures.)

And a bit of insulation above the fixture. This keeps the heat away from the wires.
Billy_Bob is offline   Reply With Quote
Old 01-31-2010, 08:36 PM   #6
Member
 
Join Date: Dec 2008
Location: Western Arkansas
Posts: 323
Rewards Points: 250
Default

okay to keep old knob and tube light fixtures


No I don't. Camera quit last year and I never replaced it. Where the wires connect is almost like a 'bell' on a ceiling fan. The part that goes up against the ceiling and hides the wires and fan support. These are not fancy fixtures, I just prefer to keep them. If I could find a small enough pancake box and mount it directly on the ceiling whats the maximum gap allowed between the box and the lamp bell or is there one? Seems like anything would be better than the 'no box' situation.
Mike in Arkansas is offline   Reply With Quote
Old 01-31-2010, 08:56 PM   #7
Member
 
Join Date: May 2009
Location: Brooklyn, New York (NYC)
Posts: 1,124
Rewards Points: 500
Thumbs up

okay to keep old knob and tube light fixtures


Quote:
Originally Posted by Mike in Arkansas View Post
No I don't. Camera quit last year and I never replaced it. Where the wires connect is almost like a 'bell' on a ceiling fan. The part that goes up against the ceiling and hides the wires and fan support. These are not fancy fixtures, I just prefer to keep them. If I could find a small enough pancake box and mount it directly on the ceiling whats the maximum gap allowed between the box and the lamp bell or is there one? Seems like anything would be better than the 'no box' situation.
IMHO a Pancake box would fit between the ceiling and the fixture (the way you describe it). Even though I don't know that specific fixture, there are still in the residential market replacement fixtures similar to the "Bell" shape that you describe, which will accept the old style "Flat" boxes that are anchored on a joist. Those are (still) found all over NYC.)!!

Advertisement


Last edited by spark plug; 01-31-2010 at 08:58 PM. Reason: Failed to capitalize & proper place of Parentesis.
spark plug is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Knob and tube neutral question gbwillner Electrical 2 11-07-2009 10:34 AM
knob and tube question marin001 Electrical 7 12-21-2008 04:49 PM
expanding knob & tube wiring jadrma Electrical 12 11-19-2008 05:27 PM
Knob & Tube wiring - How concerned should we be? hotdiggitydog Electrical 6 04-11-2006 08:52 PM
How safe is knob and tube wiring? jackdp Electrical 8 10-29-2005 11:50 AM




Top of Page | View New Posts