Ugh...big change for NM cable and SE cable. The bending radius requirements were drastically increased. This is going to change how you wire buildings.
I can say this, I have done electrical work for 50* years and the last few years I have been working with a friend of mine who does fire forensics (electrical) for the state and different entities. Every and I mean every instance where a wire had melted and shorted, every bend and every spice upstream towards the panel formed a high impedance point and prolonged the opening of the breaker. In most cases also melted at those points and when they were melted, every time it was at a sharp bend and a splice. There are several reasons why this happens and too much to write about here but as for the bends it involves literally the conductor properties being changed as the wire is being bent, Being stretched on one side and being compressed on the other. That little bit of deformation makes a big difference not to mention the same effect on the insulation. Bends in wire is more critical than what everyone thinks, From data cabling to lightning protection systems and even romex!
This change makes no sense, is ridiculous, and could become problematic. I wish I knew the rational behind the board in making this change: as Mr. J- acknowledges, common sense stated that the radius should be determined by the width of the cable along the axis of the bend.
There is no guessing you go to the manufacture of the cable itself, and they have their white papers and lab testing that gives the measurements of allowable Ben’s for each manufacture. No interpellation by somebody no guessing black and white fact on a paper from the manufacture
I guess the days of the 3 lb hammer with a 2x4 are going away........
Bending the wide way you also have the conductors under different tension trying to come in line with each other.
Was there any rationale for this given when it was under discussion, other than just clarifying something that was ambiguous?
I can say this, I have done electrical work for 50* years and the last few years I have been working with a friend of mine who does fire forensics (electrical) for the state and different entities. Every and I mean every instance where a wire had melted and shorted, every bend and every spice upstream towards the panel formed a high impedance point and prolonged the opening of the breaker. In most cases also melted at those points and when they were melted, every time it was at a sharp bend and a splice. There are several reasons why this happens and too much to write about here but as for the bends it involves literally the conductor properties being changed as the wire is being bent, Being stretched on one side and being compressed on the other. That little bit of deformation makes a big difference not to mention the same effect on the insulation. Bends in wire is more critical than what everyone thinks, From data cabling to lightning protection systems and even romex!
Normally the NEC is all very logical but this one seems ill conceived.
This change makes no sense, is ridiculous, and could become problematic. I wish I knew the rational behind the board in making this change: as Mr. J- acknowledges, common sense stated that the radius should be determined by the width of the cable along the axis of the bend.
about time!
Is this to sell more cable?
Reality: Easily ignored. Common sense takes precedence.
There is no guessing you go to the manufacture of the cable itself, and they have their white papers and lab testing that gives the measurements of allowable Ben’s for each manufacture.
No interpellation by somebody no guessing black and white fact on a paper from the manufacture
You use the width of the cable and follow 334.24. Nothing more to it than that.