NM connector inside FS box?

[S Miller]

This happened last month and we (guys at work and myself) have varied opinions:
Our new guy was installing a generic spot light/motion unit over his neighbors garage. The unit came with the floods, motion unit, backing plate and a round FS box (a DIY store generic package deal with UL stamp). The box had a threaded "boss" in the center of the back to thread in a connector. He ran the wire thru the attic, drilled a 1/2" hole thru the fascia and put the NM-B thru the hole and into the box. To avoid drilling a 1 1/4" hole (big enough to swallow the connector) in the fascia he pushed the wire in the box, put a connector on the wire inside the box, tightened the 'pinch' clamp, spun the box on the connector to make it tight, then mounted the unit. Now we're all scratching our heads. We all said this is a violation but since we've been talking about it, nobody can come up with a section. Now we're wondering if this is a violation or just something we've always done a certain way.
We have looked at this as follows:
1) Violation of 'install as per instructions from the mfg'. Prob is, there are no instructions, not even any pictures (Arlington industries made this connector). We looked on the box, in the catalog and went online and can't find anything from the mfg that tells which way the wire goes in the connector or the connector in the box.
2) Box fill violation: no, there's nothing but a single 12-2 in an 18" box.
3) Inability to adjust the pressure after installation. Actually it's more accessible than if it were outside the box, we just need an offset screwdriver.
Your opinion? What are we overlooking? (or did our rookie come up with a shortcut we all should have thought of years ago?)

[Jerry Peck - Codeman]

We all said this is a violation but since we've been talking about it, nobody can come up with a section. Now we're wondering if this is a violation or just something we've always done a certain way.
We have looked at this as follows:
1) Violation of 'install as per instructions from the mfg'. Prob is, there are no instructions, not even any pictures (Arlington industries made this connector). We looked on the box, in the catalog and went online and can't find anything from the mfg that tells which way the wire goes in the connector or the connector in the box.

That would be correct.

The backward installation of the adapter as described would be a violation of:
- 110.3(B) Installation and Use.
- - (B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

You are looking only at the instructions, lack thereof, for labeling and manufacturers' installation instructions, whereas 110.3(B) includes and also refers to the listing instructions.

The listing instructions would be the standard to which those clamps are tested, and to install one backward as you described and have it be compliant with the code and its listing and labeling the clamps would have had to have been installed backward as described, tested that way, and thus would be listed that way.

Doing so would raise all kinds of questions, including, but not limited to:
- Was the adapter tested installed backward?
- Is the clamping mechanism designed and tested to resist the correct minimum stress without damage when the NM-B cable is pulled inward into the adapter rather than outward out of the adapter?
- Is the inward end of the adapter been tested with the cable being pulled inward and abraded by the inner surface of the backward adapter?
- Does the adapter design itself support what effectively is "pushing" on the cable when it was designed and tested to resist "pulling"?
- Is the clamping end of the adapter suitable for a bushing surface when installed backward and the outer sheath of the cable is stripped back at the clamping device?
- The cable is now running through the threaded hub with no protection from damage from contacting the threads as the adapter is now screwed in from the inside of the box and not the outside of the box, leaving "however many" threads exposed and unprotected.

2) Box fill violation: no, there's nothing but a single 12-2 in an 18" box.

And what you count that backward adapter as? There is nothing which relates to the space it takes up within the box.

3) Inability to adjust the pressure after installation. Actually it's more accessible than if it were outside the box, we just need an offset screwdriver.

Why would you need to "adjust pressure after installation"? Either the adapter had the cable properly placed in it and properly clamped, or it did not. If the cable was not properly placed and clamped in the adapter, then its installation would not have been acceptable to start with.

How are those for starters to get the discussion going?

[S Miller]

Thanks Jerry. That's where we were heading, just couldn't quite justify it. We had eliminated the box fill issue figuring there was no allowance needed for a proper clamp so for the 'head' we could allow 3,4,5 wouldn't matter there's plenty of room. However that brought up the issue of the potentially sharp edges of the clamping mechanism which we figured would be a sufficient enough point to void the reverse installation by itself. The "inability to adjust" point was just thrown out there by one of the guys. We had pretty much decided it was irrevelent.
As you can see, we've been having fun with this (at the expense of our new guy). Now, with your added comments we'll really give this kid a hard time. He wouldn't fall for the old "That's the righted handed bender, I need the left handed bender" routine so we'll have to pick on him with this. Isn't life great