Correct screws for metal box

[Nick M]

Is there something in the electrical code which states what kind of screws should be used for attaching metal electrical boxes to wood studs? Are any pan/button head acceptable where flat heads are not? Curious about this one.

 

[Aceman]

As long as it's secure I'm sure the inspector won't care.

That said, we do use pan heads for 99% of the work we do, including installing boxes on studs.

 

[kbs2244]

Most often I use 1 1/2 long black drywall screws.

Nobody has complained yet.

 

[Falcon67]

Pan head screws for neatness, drywall screws because they are usually handy. Nails work too.

 

[Norcal]

Drywall screws have no shear value & look unprofessional.

 

[green.bubbly]

Drywall screws have no shear value & look unprofessional.

You know I gotta ask because I do not know any better but how much shear strength is needed to hold up a box behind drywall?

 

[chickenhauler]

Depends how hard you sledge the drywall.

 

[Teken]

You know I gotta ask because I do not know any better but how much shear strength is needed to hold up a box behind drywall?

If you have hospital grade outlets installed you will notice the amount of force to remove a plug from the wall to be almost 300% more difficult to remove out of the wall.

Over time the flexing *may* cause the dry wall screw to snap.

Have I seen this in the real world, nope . . . But, can attest that depending upon the electrical outlet quality.

Those sons of ******* are very hard to pull out a plug, which causes huge tension and stress on the box.

 

[darkk]

I keep hearing that drywall screws have no sheer strength. I have 8 shelves that will argue that point with you. You would not believe the amount of weight I have on them. They have been up for around 8-9 years with this load and the items are continually changed so it sees a lot of use.

 

[green.bubbly]

If you have hospital grade outlets installed you will notice the amount of force to remove a plug from the wall to be almost 300% more difficult to remove out of the wall.

Over time the flexing *may* cause the dry wall screw to snap.

Have I seen this in the real world, nope . . . But, can attest that depending upon the electrical outlet quality.

Those sons of ******* are very hard to pull out a plug, which causes huge tension and stress on the box.

Thanks. That is why I ask.

 

[Norcal]

I keep hearing that drywall screws have no sheer strength. I have 8 shelves that will argue that point with you. You would not believe the amount of weight I have on them. They have been up for around 8-9 years with this load and the items are continually changed so it sees a lot of use.

The reason they have no shear strength is that they are hardened & if exposed to the wrong force(s) they will snap.

 

[walrus]

I'd like to see someone snap a dry wall screw off pulling a plug out of a receptacle, that would be quite a feat. Maybe if you torqued them to the point of snapping, other than that I don't see it happening.

 

[Torque1st]

The cheap Asian pan head screws we get will probably fail before drywall screws.

Just remember that no matter what type of screw you use you MUST strip out the drive splines during installation.

 

[ishiboo]

I'd like to see someone snap a dry wall screw off pulling a plug out of a receptacle, that would be quite a feat. Maybe if you torqued them to the point of snapping, other than that I don't see it happening.

Torque is exactly that. In a double box, removing a plug from the outlet farthest from the wall does generate a lot of force. Likely to be an issue, no, but there are better options.

I HATE drywall screws for anything other than drywall. They rust like nobodies business, they're often poorly formed (ever drive a screw in with your fingers and have a burr from the screw slice into it? that ***** balls) and they have zero shear strength.

I use them only for drywall. For general purpose, I use all T25 zinc phosphate construction screws. Easy to drive at an angle and the bits are unlikely to strip.

 

[walrus]

I use them only for drywall. For general purpose, I use all T25 zinc phosphate construction screws. Easy to drive at an angle and the bits are unlikely to strip.

I use torx head screws also. The ones I use are rated for pressure treated, I forget what they are called. I like truss head for mounting equipment. If I use dry wall screws for anything I use galvanized ones.

 

[chickenhauler]

Just remember that no matter what type of screw you use you MUST strip out the drive splines during installation.

As often as I have to use a pry bar and sledge, I sometimes think that actually was a requirement.