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-   -   Nicks on electrical wiring (http://www.diychatroom.com/f18/nicks-electrical-wiring-23570/)

tripower 07-12-2008 05:41 PM

Nicks on electrical wiring
 
I heard that any nicks or scrapes on the ends of electrical wiring, for instance the connections to outlets, could cause them to overheat. Is this true for even a couple of nicks or scrapes? Do these connectors need to be perfectly smooth?

fw2007 07-12-2008 08:53 PM

First off, let me tell you that I am a bit of an obsessive-compulsive when it comes to doing electrical work. I do not usually tolerate any imperfection in the wiring.

Whether a particular nick or scrape will cause a wire to overheat, depends on physics. If the conductor has a nick or scrape which reduces the cross-section of the conductor to a point where the conductor cannot safely carry the rated current, then yes, it will get warm/hot and cause a problem.

The second issue is physical strength. If a nick or scrape causes the conductor to become physically weakened to the point where it may break or further deteriorate when the receptacle is being pushed into the box, then this is a problem.
I think it is logical to say that if the conductor is damaged to the point where it's physical strength is in question, then it would be a problem electrically as well.

I always leave extra length on all wires coming into a box- so that I can afford to make a mistake or two, needing to cut and re-strip the connections.

FW

Longtooth 07-12-2008 09:01 PM

Mechanical wire strippers will nick the conductor if not properly set. Nicking an aluminum conductor will cause it to break. It's a simple test, try it on some scrap first.

tripower 07-12-2008 09:47 PM

Quote:

Originally Posted by fw2007 (Post 138544)
First off, let me tell you that I am a bit of an obsessive-compulsive when it comes to doing electrical work. I do not usually tolerate any imperfection in the wiring.

Whether a particular nick or scrape will cause a wire to overheat, depends on physics. If the conductor has a nick or scrape which reduces the cross-section of the conductor to a point where the conductor cannot safely carry the rated current, then yes, it will get warm/hot and cause a problem.

The second issue is physical strength. If a nick or scrape causes the conductor to become physically weakened to the point where it may break or further deteriorate when the receptacle is being pushed into the box, then this is a problem.
I think it is logical to say that if the conductor is damaged to the point where it's physical strength is in question, then it would be a problem electrically as well.

I always leave extra length on all wires coming into a box- so that I can afford to make a mistake or two, needing to cut and re-strip the connections.

FW


I would say I am the same way. I am not talking about major nicks or scrapes but just the stray light nick or light scrape. If you use standard needle nose pliers I don't know how you do an entire set of outlets without at least a few teeth marks on the connector ends.

gregzoll 07-12-2008 09:51 PM

When you Strip the end of a conductor, there may be a small ring, but in the Military, if you nicked the end while stripping, or it appeared to show damage on the connecting end, you cut the wire, and re stripped.

As long as the Insulating covering, or jacket is not damaged, or the wire is not kinked or twisted, which can factor into overheating, you would not see problems. Only way to tell if there is overheating, is to place a temp probe on the wire while under load, and seeing if it is within nominal operating temps.

Yoyizit 07-13-2008 08:25 AM

A solid wire without nicks can withstand repeated bending better, no?

jerryh3 07-13-2008 08:41 AM

I was under the impression that the biggest problem with a nick in the wire was the possibilty of arcing across the nick.

Yoyizit 07-13-2008 09:33 AM

Quote:

Originally Posted by jerryh3 (Post 138642)
arcing across the nick.



Arcs require a voltage high enough to overcome the dielectric strength of air.
http://en.wikipedia.org/wiki/Electrical_breakdown
The un-nicked portion of the wire short circuits any voltage across the nick.
Maybe I don't understand your question. . .?

jerryh3 07-13-2008 09:50 AM

Quote:

Originally Posted by Yoyizit (Post 138650)

Arcs require a voltage high enough to overcome the dielectric strength of air.
http://en.wikipedia.org/wiki/Electrical_breakdown
The un-nicked portion of the wire short circuits any voltage across the nick.
Maybe I don't understand your question. . .?

Ok. I'm corrected. What part of Maryland are you in?

Yoyizit 07-13-2008 10:02 AM

what part
 
12 miles NW of the once-famous Mayflower Hotel.
Poor Mr. Spitzer.

jerryh3 07-13-2008 10:14 AM

Quote:

Originally Posted by Yoyizit (Post 138663)
12 miles NW of the once-famous Mayflower Hotel.
Poor Mr. Spitzer.

Potomac?

Yoyizit 07-13-2008 10:46 AM

Potomac
 
Close enough for gov'mint work!

fw2007 07-13-2008 03:50 PM

TriPower;
I don't think the abrasions caused by a needle-nose plier will do any harm. After all, how else are we supposed to wrap the wires around screws of outlets, etc?
I suppose if you use back-wired you don't have that problem, but I prefer side-wired.

FW

tripower 08-30-2008 04:05 PM

Quote:

Originally Posted by gregzoll (Post 138566)
When you Strip the end of a conductor, there may be a small ring, but in the Military, if you nicked the end while stripping, or it appeared to show damage on the connecting end, you cut the wire, and re stripped.

As long as the Insulating covering, or jacket is not damaged, or the wire is not kinked or twisted, which can factor into overheating, you would not see problems. Only way to tell if there is overheating, is to place a temp probe on the wire while under load, and seeing if it is within nominal operating temps.


What would be the normal operating temps?

jrclen 08-30-2008 08:03 PM

Quote:

Originally Posted by tripower (Post 153322)
What would be the normal operating temps?

In Florida or in Alaska?


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