As far as altering the listing of the box goes. I know that boxes are listed to be used with hardware that has certain specifications. I don't question that Pierre is right.
Pierre C Belarge said:
I believe that the portion of the box that accepts the screw has been designed for a 6 or 8 size shank, depending on if it is a device or fixture box. If a screw of large diameter is used, it will put excessive pressure on the wall of the box, and in some instances the pressure splits where the screw is inserted. I have seen this many, many times as I am sure others here also have.
Each AHJ has to decide how far to press each issue. We could spend all day at one house taking apart every joint and looking at every screw and nail but then we would need 10 times the number of inspectors and a budget to match.
We don't want to micromanage every fastener choice. So we see what products are realistic common problems and concentrate on those. We won't approve anything installed with a drywall screw but beyond that, the contractor is pretty much free to use whatever type of fastener they think will get the job done and if they choose one that's too big for that particular box and is not listed for that application, then they take responsibility for whatever damage is done to the box.
Our view of drywall screws is as Mike once posted
Mike03a3 said:
The black drywall screws have a coating that protects them against corrosion from the chemical composition of the drywall. As a byproduct, they are very brittle. Even a cursory google of the internet will bring up thousands of cautions against using them in applications requiring any real strength. As many have already said, they are especially poor in shear strength.
If other types of screws are used in a job that passes inspection, that doesn't mean we agree with the choice or have determined that it's the proper screw. Just because a job is inspected doesn't mean that the contractor is free from responsibility or liability. The contractor always bears the most responsibility for his job, more than the inspector. Our time on the job is extremely limited and is only a quick snapshot of the job as it stands at one particular moment.
If we say we will accept any screw except a drywall screw that doesn't mean that we're certifying the compatibility of whatever fastener the contractor chooses with the box it's used on.
In a way, we're just picking our battles wisely to use our time to accomplish the most good. We can't drive ourselves crazy backing out and examining every little screw and trying to determine its compatibility or listing for that particular equipment.
David