Landing stranded wire on screw terminals

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iwire

iwire

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meternerd said:
What's wrong with spade lugs? In the nuclear industry, we were never allowed to use stranded wire without lugs. Safety and reliability is a BIG deal! Takes little time and works great. All I use when terminating strands under a screw. All my experience is utility or industrial, though.
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Consider this.

Until recently it was a listing issue using spade lugs on a device.

By adding spade lugs you have doubled the number of terminations. More terminations results in more points of potential failure.
 
jumper

jumper

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meternerd said:
What's wrong with spade lugs? In the nuclear industry, we were never allowed to use stranded wire without lugs. Safety and reliability is a BIG deal! Takes little time and works great. All I use when terminating strands under a screw. All my experience is utility or industrial, though.
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I assume you mean fork terminals. It just that they introduce one more point of possible failure. Many gov specs call for them, but I do not see them as better than a standard termination, perhaps cleaner depending on the person doing the work.
 
Jraef

Jraef

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Electrical Engineer
jumper said:
I assume you mean fork terminals. It just that they introduce one more point of possible failure. Many gov specs call for them, but I do not see them as better than a standard termination, perhaps cleaner depending on the person doing the work.
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I did a project for the Corps of Engineers on a dam. They insisted on RING terminals! Talk about a PITA...

Some wiring devices make the screws captive, i.e. the ends of the screw threads are mashed after inserting the screws in the connections so that they can't be backed out all the way without stripping out the hole threads. I can't remember which ones I found that let me remove the screws, but I had to test a lot of different brands before I found it.
 
M

MD84

Senior Member
Location
Stow, Ohio, USA
jumper said:
Why not use a back wired pressure plate receptacle? Easiest solution if you struggle with stranded wire.
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+1. THIS is what I stock on my truck. I prefer not to terminate stranded wire on screw terminals and most the time I do not have to. These are great because they come with one of the screws already tightened. One just strips the wire, insert into back and tighten. A real time saver.

K8MHZ said:
That's fine until the insulation comes off and leaves a 1/2 inch or so of bare conductor sticking out.
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One only needs to leave a very small amount of insulation on the end of the wire. About an 1/8th inch will work just fine. This works very well IMO. I typically use my Klein Katapult strippers and with practice it is quite easy to strip the wire and leave the insulation just barely on the end of the wire. It is terminated and then the insulation is pulled off for a clean and precise job.
 
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ggunn

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Electrical Engineer - Photovoltaic Systems
MD84 said:
+1. THIS is what I stock on my truck. I prefer not to terminate stranded wire on screw terminals and most the time I do not have to. These are great because they come with one of the screws already tightened. One just strips the wire, insert into back and tighten. A real time saver.



One only needs to leave a very small amount of insulation on the end of the wire. About an 1/8th inch will work just fine. This works very well IMO. I typically use my Klein Katapult strippers and with practice it is quite easy to strip the wire and leave the insulation just barely on the end of the wire. It is terminated and then the insulation is pulled off for a clean and precise job.
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Some electrical/electronic components come with leads already stripped that way.
 
mgookin

mgookin

Senior Member
Location
Fort Myers, FL
K8MHZ said:
Don't the also have some glue on the end to keep the insulation from falling off?
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We get devices by the pallet with the pre-strip hanging off the end. I've never seen glue and I can't see how they'd get it in there if they wanted to. It keeps the strands from becoming disoriented while handling.

I considered the spade terminals after it was suggested on here. There are some reasons which support using that process (prepped in advance, neat, easy for final assembly, etc.) so I researched what size that screw is. UL only has minimum screw and minimum TPI metrics, nothing absolute.

Spade terminals got set aside when someone suggested back wiring (clamp) which some receptacles have and some don't. When a manufacturer's specs on a receptacle says "back and side wired" you get the clamp which tightens by turn of the screw. When the spec says "push-in and side wire" you don't get that clamp.

We have lots of options on the table to choose from. Thanks to all who have provided information.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
MD84 said:
...
One only needs to leave a very small amount of insulation on the end of the wire. About an 1/8th inch will work just fine. This works very well IMO. I typically use my Klein Katapult strippers and with practice it is quite easy to strip the wire and leave the insulation just barely on the end of the wire. It is terminated and then the insulation is pulled off for a clean and precise job.
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IMO leave a lot—1/2" plus—then either leave it on (tape it back to itself if you are leery of the insulation coming off) or cut wire off flush with rear of device after tightening the screw.
 
R

rlundsrud

Senior Member
Location
chicago, il, USA
MD84 said:
I try to avoid using stranded wires on screw terminals. When I do it I like to leave a small section of the stripped insulation on the end of the wire. This keeps the strands from coming apart.
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I concur on this method, I call it the aglet strip. If you wrap the receptacle with tape it will keep the insulation from coming off. It is my preferred method, hands down.
 
D

Dave047

Member
Location
Pikesville, Maryland
stranded wires under screws

stranded wires under screws

By definition stranded wire is a flexible connection. Does the code not require flexible connections to be terminated with a terminal ( sta-kon) connection on a screw unless the screw is rated for this( i.e. a breaker terminal screw)
 
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