Hi Everyone, Got a few quick-ee Q's to throw at 'ya;

At work yesterday, a guy I am working with mentioned that one of the Sparkys in the company is currently inroled in some type of trade schooling. The guy said it was College class for Electrical Engineering, but the descriptions sound more like an NEC code class. That's not relavent, but felt that everyone should know [ joke].

Anyhow, he mentioned two conflicting things:

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[*]Pre-Twisting conductors prior to landing a Wirenut is not allowed anymore, due to the increased Resistance, therefore is non-compliant [I know what your thinking, I had the same reaction of ???] and

[*]Taping the sides of Receptacles is non-compliant [got me what this is about ]
</OL>

Is there any validity to these claims per any code or Electrical Engineering studies currently taught???

I'll post this topic in the Holt forum and the IAEI forum [it's been over a year since I have even browsed the IAEI forum! hope I can still get a post in].

Anyone heard of this, or is this just a case of mistaken information [my first and last guess]?

Thanks in advance! [TIA]

Scott SET.

The "no pre-twisting" may come from the statement on some wire nut containers that says "pre-twisting not required". It doesn't say that you can't pre-twist them. I can't think of any reason for the no tape rule. With solid wire, I always pre-twist the wires with my Kliens, and if the box is especially tight I have been known to tape up switches and receptacles, of course that was when we could work things hot.
Don(resqcapt19)

Don is giving away his age(& probably mine) with his comment about taping & working hot.

I'd sure like to see the code citation about not taping receptacles.

As far as twisting is concerned, Don is correct. After all, Buchannon supplies a wire nut driver that is just about gauranteed to twist the wires unless you crank down the clutch on your cordless drill to a very low setting.

Tom

[This message has been edited by Tom (edited 12-27-2001).]

Recent IAEI meeting, see question 66.

http://rockymountainiaei.netfirms.com/CodeQuest.html

66. An area inspector has turned down installations because the electrician had not twisted the wires before installing spring connectors (wirenuts). Is this a valid position?

No. Section 110-3(b). They are not pre-twisted during UL tests. In fact, pre-twisting can possibly alter the "torquing effect" of the connector’s design. (Incidentally pre-twisting negates the benefit of these connectors. They do not have to be pre-twisted as you would for wrapping with electrical tape.)

Installation Instructions usually found on the smallest unit container (or inside bag) do not state to pre-twist the connectors.

Chapter,verse,section & or listing requirment should take precedence over personal choice.

The items that Joe has presented bring light to this discussion.

I mentioned that the Manufacturers do not specify the conductors must be pretwisted, so that would rule out anything on that side [such as the turned down inspection for not twisting the wires].

It's obvious to me that UL would not pretwist, so that gives the Manufacturers "No need to pretwist" angle more validity.

Now, seeing people in the trade use the wirenut twister bit [for cordless drills], or the hand crank twisters - which are produced by the same Manufacturers which make the wirenuts being installed - I wonder if this is acceptable?

Like everyone else, I have been pretwisting conductors [with Linemans' pliers AKA "Kliens"], trim them as needed, then land the wirenut firmly enough to hold as an Insulator to the splice - rather than the sole conductor. This equals out to a tightness which does not distort the wirenut, nor pulls apart from the "Tug Test".

I'll have to print this thread out and present it.

It will be almost impossible to not pretwist after doing so for 18+ years!!!

Now as to the taping of Receptacles thingee, that one just sounds weird!
I would like to see a design or safety issue concerning this!

Scott SET

Scott:

I could not find anything in the UL white book that prohibits pre-twisting. I always used my long nose pliers, and lineman pliers and twisted the wires before using a
wirenut.

The use of tape at receptacle, or other device or equipment termination screws is just some additional insurance that one will not get a shock when replacing receptacles, because they forgot to turn off the power!

I was taught by my dad early on to use tape and I still use tape to protect myself!

Like most anything else, the pre-twisting can be done incorrectly.
I've run across a high number of failed connections where the wires were pre-twisted to the point that the diameter of the twisted conductors was large enough that the wirenut couldn't get any purchase on the connection. The wire nut in this case serves no more purpose than that of a piece of tape. Very often the wirenut has fallen off as soon as I touched it.
Also, I've found connections where 1 or more of the conductors has slid back from the rest when twisted and makes poor contact or none at all.
I've never been a "pre-twister", and only know of a couple of connections I've ever had fail.(in 30+ yrs)
My big gripe is with the use of wirenuts out of their listed range. It seems like some people think that they only come in one size...Red. Anything from 2-#18 to 7 or 8-#12 get stuffed in them. (The yahoos that overfill them often wrap them with tape to keep them from falling off). This has been the singlemost often cause of failures I've run into personally, and most commonly have been on neutrals because more of them are tied together in a box on multiwire circuits. (Naturally, because this is the most destructive connection to lose!)

I have looked at the instructions for wirenuts from: 3M, Buchanan, Gardner-Bender, Thomas & Betts, and Ideal. All of the instructions allow for pre-twisting or no pre-twisting, it appears to be the installer's choice.

The problem with pre-twisting is not the final twist of the conductors. There are two areas of concern, first damage to the conductors done by the jaws of the tool. Second, the loss of contact between some conductors and the spring of the wire nut (for example a #18 ballast lead may be hidden in the twist creases of (2) #12).

I'm with you there Joe. but would add that i've had enough painters & wallpaper guys remove my plates and do things that someone with a shread of respect for electricity would not...

i spil baaad .....



[This message has been edited by sparky (edited 12-28-2001).]

Anyone ever worked in a building where circuits are not allowed to be turned off? I've worked in many highrise buildings in downtown Houston. Ever been waiste deep in a lay-in or spline ceiling adding a receptacle onto a hot circuit, you back the wire nut off the neutral, and the joint comes apart in your hand? Been there, done that... Ever come behind another contractor who has put about 9 extension rings on a 1900 box (4" square box)? After digging through about 50 joints, you pull out the circuit you need, and it falls apart in your hand. I'm a twister, and a taper. Above are just a few reasons why I tape, and twist. I'm not knocking anyone who doesn't, but it seems like I've had bad experiences coming behind those who don't.
This is not a new subject. It seems like it just comes up from time to time.
HMEL #688

Notes from the real world there, Watt Doctor.

Ok , let's experiement....

repeat the following twice.........

Take a piece of #12, hang from rafter,wirenut on another piece of #12, allow for wieght to be introduced at the end of this.

Lab #1--pretwist.

Lab #2---no pretwist.

Add 1 lb at @ time.....

I'll take Lab #1 for a sawbuck......

Yeah, Doc.
I've done that, but not in Downtown Houston.




[This message has been edited by electure (edited 12-28-2001).]

I'm a 'Twister' too. I can't imagine what would be wrong with taping a device. I've always done it. Found a few photos in our Archives that demonstrate some of the things being talked about here.

This is one of Joe T's that is a Favorite of Mine;


This one was taken after a wirenut fell off when touched;
(See what's wrong??)

Scott,

I've come to think of this as the religion of wirenuts.

I believe the better wirenut is one that has a void builtin between the insulating shell and the spring wire coil cone. As a group of conductors are tightened into the nut, the spring wire coil cone deforms, it expands as it cuts into the sides of the conductors, a process that creates more drag as more conductor is "threaded" into the constriction of the coil, to the point that the conductors are twisted. In my opinion, the twisting of the wires by the wirenut itself results in the greatest surface contact between conductors that can withstand the dynamic state of contact that exists as the wires change physical size when heated and cooled by load and ambient conditions. When the conductor ends are placed together, untwisted, and tightened into the wirenut, the spring wire coil cone expands only, with no relaxation.

The spring wire has a memory. When deformed, the coil only partly returns to its original shape. When I remove a conductor from a wirenut, I install a new wirenut.

While not as pronounced as removing a conductor, I maintain that pretwisting and cutting off the excess results in a similar looseness in the spring wire. When the copper strands are twisted, the copper's own memory will result in a slight relaxation in the twist. When the cutter removes the excess, the circular grouping of strands is crushed ovate, significantly oval, and adds a "set" to the relaxed grouping of strands. Now, when the wirenut is applied, the spring wire is stretched wider than the diameter of the conductor bundle by the long dimension of the oval cut end until cutting and compressive forces overcome the "set" and finally start recompressing the twist in the conductors. In my opinion, part of the spring, a few turns, at least, will have been overstretched and be in contact with the conductors only by virtue of the memory of the spring wire, therefore with less force.

The connection I close up in the j-box is one that will be moving for the next hundred years. . .hopefully . . .and I want the spring that is designed to follow that movement to be in the peak of its compressive force range, therefore, I don't pretwist. The labor of twist and trim I apply to getting the ends together so I have no pullouts.

Al,
I'm right with you when it comes to replacing a wirenut that I have removed. I would say that 7 out of 10 times that I remove a yellow wirenut, it goes into the trash. When I remove a red, I use my best judgment as to whether I chunk it. A grey or blue is practically indestructible, and I would very rarely throw one away.
Your case stated above is very sound. I only have one argument against it. The spring inside of a wirenut is conically shaped (did I say that right? I mean shaped like a cone). I would think that the "overstretching" portion of your argument would be negated by this fact.
IMHO the mechanical strength of the joint shouldn't rely on the wirenut. I want the joint to stay connected without the use of a wirenut, and the wire nut to provide the insulation. If you remember, they used to solder all joints, and then apply insulation. I've never broken an old soldered joint that wasn't twisted.
While I'm on my soapbox, let me throw something else into the mix. Take a knife for example. The reason that some knives are serated is because a serated knife has more cutting surface in same the length as a regular blade. So, a knife with a 4" blade that is serated may have 4.25" of cutting surface. I'm not an engineer, but I just wonder if the same principal applies to twisting wire together. Twisting provides more surface contact? Maybe?
HMEL #688

[This message has been edited by The Watt Doctor (edited 12-30-2001).]

OK, You guys know my feelings on this from another thread started last August (that seems to have been removed?). I use Ideal Wirenuts, and a wrenching tool. No pretwisting, but the final outcome is superior, the twists are there and a tighter "weave" is achieved.



The top pair of wires was pretwisted, the bottom pair was not. See any difference?

I'll shut up now.


[This message has been edited by sparky66wv (edited 12-30-2001).]

Hello everyone, Thanks for all the replies!!!

Been REALLY busy this week, so please excuse the delayed response[s] on my side

I printed some of this thread and presented as much info to the guy who brought this whole thing "to light" [the person who mentioned all this stuff to me].
I'll print this new stuff, plus what has been added to the redundant threads going in the MHE and IAEI forums, mainly because even after presenting all kinds of information, the guy is still going on what the other dude said only [with no regards to the "what-if's", "why's" and "what-not's" included].

My preferences to pre-twisting are primarily to get a solid and tight splice, which doesn't seem quite right [to me] without pre-twisting ... but that's just my over analysis nature
The other is just like what others have mentioned - the hot wire springing out of the wirenut and ground faulting... in your face!

It's not a real major concern 100% of the time for me, as I opt to kill circuits unless they just absolutely have to be live - even then you have the possibility of barbecuing someones PC power supply, etc. with open common grounded conductors [AKA open neutrals]. Nevertheless, if the common opens, the PC reboots - and that user loses all the work from since the last save was done [if saves are done!]. If lighting circuits, then the lights go down and such other chaos
[should be Kaos...agents ].

In the multifloor buildings, ground faulting the 277 VAC lighting branch circuits runs the risk of tripping the GFPE main breaker - then EVERYONE is pissed!!! [excuse the language].
The job I have been on over the last few weeks is the typical remodel / T.I. office space project, and is in a 12 story building.
When the original walls were demo'ed, there was a couple of Electricians on-site to "attempt" to stay ahead of the demo monsters, killing as much as they could.

One very anxious demo guy decided to knock a wall down which had "a,b" switches for the 277 VAC lighting in one small office. From what I heard, just as soon as this guy's sledge hammer broke the 4s box loose from the steel studs, the circuit ground faulted [a very sparky one, as from the looks of the effected 4s box]. That tripped the GFPE main and the whole building went down.

Sounds fun, doesn't it?

I guess the only things heard were the popping ground faults, the sounds of people asking "what happened to the lights?", then the E-Power's diesel prime mover starting!!

For the tape deal, that one is really silly! The wirenut / pre-twist situation has merit, but the taping of Recepts / Switches just sounds kooky!

Once again, thanks to everyone for the responses!!!

Scott. SET

Virgil,

Unless a post ends in Flames or is definitely giving out very poor information safety-wise it is not removed. I don't remember anything like that with this thread, do you?

There may be a glitch going on here. I see that the Forum control panel has some options for some debugging but I don't know anything about them. I think that if the post was removed it would not show up in the search results.

Bill

Bill and Virgil:

Yes, I remebmer a thread that was on the Violations Forum here that I moderate, and I probably deleted it trying to clean up a little.

It was very similar to this one, and I remember that Bill posted a few wirenuts that were green in color with holes in the top.

Just to add more here how about this "RED" wirenut on the EGC's?

No problem, didn't mean to sound defensive...

Just wondered why I couldn't find it!

Joe,

No, the thread was in the General area it says. It seems that the Forum software kinda admits that things might get lost sometimes because they mention some steps to take. I may have to start archiving things or something like that (?)

Bill

My wirenut of preference has always been the Ideal tan Twister wirenut. (Although I do have the slotted panel screwdriver from Ideal that will tighten red and yellow down with a nice twist on the insulation.) I find that the Tan wirenut holds a wide range of wire sizes that I use and has enough leverage to put a nice twist on it.