An Odd Question.

[TripCurve]

Hello all,

I wasn't to sure where this question would fit so I posted it in NEC (feel free to move).

Currently work as an Electrical Engineer.
OEM/Integrator.
Design to UL 508 and NEC Guidleines.


During a ring down/test of some equipment today I found that insulation was being crimped under termination points (Terminal blocks, Contact/Pressure Plates). When asked why this was being done the response was "It's the way we've always done it". This doesn't sit right with me because for as far back as I can remember when a wire is striped/terminated care is to be taken not to damage the conductor (no nicks, gouging, or cutting of the conductor). Crimping insulation was a no no because its creating a high resistance point. I've been looking threw the NEC book and can not pin point anything that refers to wire insulation being crimped at termination. Only wire insulation Integrity.

Can someone guide me to what I am looking for or is this just a unwritten rule?

Thanks in advance.

 

[Twoskinsoneman]

110.14(A) Terminals. Connection of conductors to terminal
parts shall ensure a thoroughly good connection

The NEC is not going to spell out every little goof you can make during installation.

We have to do what we can to comply with 110.14(A) and to me that means you don't crimp down on the insulation unless the terminal is designed for it.

 

[David C. Adkins]

I'm not sure but it sounds like you're one of the newer employees at the facility and someone who's been there longer but not necessarily brilliant with electrical knowledge is butting heads with you. Stand up for what you know, the battery in your mouse wouldn't necessarily make contact if it had tape on one one its terminal with an over sized elephant setting on it.

 

[weressl]

Hello all,

I wasn't to sure where this question would fit so I posted it in NEC (feel free to move).

Currently work as an Electrical Engineer.
OEM/Integrator.
Design to UL 508 and NEC Guidleines.


During a ring down/test of some equipment today I found that insulation was being crimped under termination points (Terminal blocks, Contact/Pressure Plates). When asked why this was being done the response was "It's the way we've always done it". This doesn't sit right with me because for as far back as I can remember when a wire is striped/terminated care is to be taken not to damage the conductor (no nicks, gouging, or cutting of the conductor). Crimping insulation was a no no because its creating a high resistance point. I've been looking threw the NEC book and can not pin point anything that refers to wire insulation being crimped at termination. Only wire insulation Integrity.

Can someone guide me to what I am looking for or is this just a unwritten rule?

Thanks in advance.

The origin of this could have been QC complaining that the uninsulated 'neck' was protruding far past the terminal, leaving live parts exposed. (This is due to the fact that improper strippibng or dull tool could put too much stress on the insulation, after cut it 'shrinks' back, away from the cut.) So in response to NEVER expose copper again is to trap the insulation under the terminal block. This however defeats the design of the terminal, except self piercing terminals which does not require stripping at all, and on power terminals it will create a fire hazard.

The proper installation of the terminal could be obtained from the manufacturer. NEC requires installation to be done according to manufacturers and/or listing agency's instructions.

 

[qcroanoke]

The origin of this could have been QC complaining that the uninsulated 'neck' was protruding far past the terminal, leaving live parts exposed. (This is due to the fact that improper strippibng or dull tool could put too much stress on the insulation, after cut it 'shrinks' back, away from the cut.) So in response to NEVER expose copper again is to trap the insulation under the terminal block. This however defeats the design of the terminal, except self piercing terminals which does not require stripping at all, and on power terminals it will create a fire hazard.

The proper installation of the terminal could be obtained from the manufacturer. NEC requires installation to be done according to manufacturers and/or listing agency's instructions.

I agree with Laszlo,
Having spent many years in Quality control it always seemed I was seeing way too much copper or I was seeing crimped insulation.

110-14.A is what I would use.