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And then there is rest of the story that makes it even more interesting: 430.9(C) Torque Requirements. Control circuit devices with screw-type pressure terminals used with 14 AWG or smaller copper conductors shall be torqued to a minimum of 0.8 N•m (7 lb-in.) unless identified for a different torque value.
Joe Tedesco, NEC Consultant
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I will of course defer to those of you with actual experience. I will accept that reptetitive torquing does make a difference.
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Joined: Jun 2005
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Sometimes connections are to tight.
Example: The square bit screw drivers on #14 solid not good. I rechecked a helpers neutral connections at panel board. loosen a couple of connections and found the wire fattened, by the Torque of square pressure connectors. almost breaking the wire in half. My fought because I told him to make sure all connections are tight! Also tried a torque wrench on 200 amp meter can to specs.,heard a snap and broke the insulator
behind the jaws. the tool is now in the storage unit.
TomL.
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Should be:"found the wire flatten"
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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Oh that is from an even more ridiculous tool: http://www.sheldonbrown.com/tork-grip.html Now Bob, I had to googgle "cold flow", as it did sound like something you would want in a connection...
Cold Flow
As compared to Creep, cold flow has no units of measure. The best description of cold flow relating to application within the electrical industry, is an excessively high rate of creep i.e. normal creep rate static load condition would be expressed in a fraction of an inch per inch of length. Cold flow, conversely if possible to measure it in definable terms, would be expressed in terms of inches of movement per inch of length. Cold flow then can be expressed as movement of appreciable magnitude occurring at a stress level in a very short length of time at an ambient temperature. Neither time or temperature are critical in assessing the effecting force of cold flow.
It is significant to realize that it is an absolute necessity to have cold flow of the conductor within a bolted connector to develop the desired low resistance contact, required for electrical/mechanical stability of the connection. So is it necessary to have cold flow of both the conductor and connector in the making of a compression connection. In these two instances a mechanical union of the two components is made by means of an externally applied force to assure both electrical and mechanical reliability. In the case of a soldered or welded connection this component union is made metallurgically. Further research on cold flow is that it is a metalurogical term for cold forming of metals. The way wire is flattened in a lug so to speak. I guess that as long as the cross-sectional area of the wire is unchanged, and there is contact equaling that dimension, you have a good connection. But if you have enough 'cold flow' to squeeze the metal out like tooth paste out of both sides of a lug, and reduce the cross-sectional area, you have over-torqued. [This message has been edited by e57 (edited 06-20-2005).]
Mark Heller
"Well - I oughta....." -Jackie Gleason
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If retorquing causes problems, I would suggest that the problmes are not solved by torquing once and going away.
I only work under 200amps and all in copper, and for that work the wrong torque will not cause any long term damage.
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I only work under 200amps and all in copper, and for that work the wrong torque will not cause any long term damage. Regardless of your opinion it is a code violation. Do you consider yourself a professional electrician or a handyman?
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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I only work under 200amps and all in copper, and for that work the wrong torque will not cause any long term damage Doing Infrared Testing I come across many copper connections under 200 amps that are overheating from torque problems. When the insulation is breaking away from the conductor don't you consider that long term damage? Also like iwire has stated it is a code violation. Al
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Here is a picture of a 200 amp connection that seems to have a problem. ![[Linked Image]](https://www.electrical-contractor.net/forum/iw/200ampburntconnection.JPG) capt al provided this picture maybe he can fill in the details. Bob
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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![[Linked Image from sheldonbrown.com]](http://www.sheldonbrown.com/images/tork-calibration.gif)
