Questions on 1960s crimped? wire nuts and box fill

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  #1  
Old 11-22-10, 01:40 PM
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Question Questions on 1960s crimped? wire nuts and box fill

Hello,

My home was built in 1961 and has ungrounded branch circuits. Most of the wiring is 12 or 14 gauge solid copper; most of the junction boxes appear to be bakelite.

I'm working to replace the original two-prong duplex receptacles with three-prong tamper-resistant ones (with a GFCI as the first outlet on each circuit).

In some of the junction boxes, I've encountered what look like crimp-on copper wire connectors being used to connect up to four conductors together. These connections are covered in black electrical tape.





Were these connectors standard practice in the 60s or am I looking at a Mickey Mouse job? If they were UL approved, is it considered best practice to leave them or cut them out and replace with standard wire nuts?

Also, for single-gang boxes like the one in the photo, is there a limit to the allowable number of conductors or cables in the box?

I have been using Leviton T7599-KW GFCIs but have sometimes had difficulty cramming them in the existing boxes. Leviton supposedly makes the X7599-W, which is considerably less deep, but no one around here seems to stock them. Is anyone aware of a similar, slim tamper-resistant GFCI receptacle from another manufacturer?

Thanks in advance for the assistance.
 
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Old 11-22-10, 02:12 PM
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Originally Posted by Jason986 View Post
1961 and has ungrounded branch circuits.
That's a little late for ungrounded. Are there tiny (16ga.) ground wires twisted around the cable clamps in the back of the box?

Were these connectors standard practice in the 60s...best practice
Standard for the time. If you're only replacing receptacles, you can leave the crimps as-is. I would consider replacing the old tape with new stuff. Use a good 3M/Scotch/etc brand, not that $0.50/roll junk. If you need to re-work the wiring in the box, replace the crimps with wirenuts or Wagos if the wire is too short for a nut.

Also, for single-gang boxes like the one in the photo, is there a limit to the allowable number of conductors or cables in the box?
Yes, but you don't need to worry about it just for receptacle replacement. I would consider replacing the old boxes with new deep boxes where you are installing GFCI devices.
 
  #3  
Old 11-22-10, 02:15 PM
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Those are Buchanan "crimp caps" and while they are irreversible (cannot be undone and used again) they are an excellent connector IF they are done properly, which those were not. Copper crimp caps REQUIRE the wires to be pre-twisted. Steel crimp caps do not require pre-twisting.

Also, the proper tool puts a four-way crimp in the cap. It looks like these were crimped with a two-way crimper.

Here's another thread on the crimp caps.

And here's the proper crimping tool.
 
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Old 11-22-10, 02:25 PM
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Those were definitely (and still are) an approved method as long as it is swaged (crimped) properly - which yours appears to be. They were used mainly where box fill is an issue, because they take up significantly less space than a nut connection. You can still get the crimp sleeves and swaging tool. The downside is a good swaging tool can run you $100, and a cheap one won't give you a good enough crimp. If you want to cut them off and nut them, that's up to you. But there's nothing wrong with that connection. A bad joint would show signs of heat damage.
 
  #5  
Old 11-22-10, 02:51 PM
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No, Matt, those connections are definitely NOT made up properly. The instructions for the copper caps are explicit that the wires MUST be twisted before adding the cap and crimping. I also have doubts about the two-way crimp being proper.

I've installed several hundred crimp caps in my day.
 
  #6  
Old 11-22-10, 06:47 PM
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Maybe it's just my monitor, but those look like brass to me, not copper. It also looks as if one of the wires in each joint was center-stripped, not done as a two-way crimp. And just sayin, if it wasn't done properly, I'd think it'd have 50 years of heat damage to the conductor and insulation, no?
 

Last edited by JerseyMatt; 11-22-10 at 07:11 PM.
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