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#92892 04/15/05 05:25 PM
Joined: Jan 2005
Posts: 71
S
Member
My inspector just turned me down for using sheet rock screws. I screwed up my panel to the studs and mast up the wall. He wrote, can't use sheet rock screws on electrical work. Has anyone ever heard of this? I've been using these screws to screw stuff up for years.

2017 / 2014 NEC & Related Books and Study Guides
#92893 04/15/05 06:41 PM
Joined: May 2004
Posts: 697
D
Member
I use galvanized screws to mount a panel to studs, but lag bolts for the mast.

The NEC uses some words such as "secured", with no definition. That leaves it open to the interpretation of the AHJ. Keep life simple...ask wkat you should use in that jurisdiction, and use it.

Dave

#92894 04/15/05 07:43 PM
Joined: Feb 2003
Posts: 687
A
Member
We buy galvanized deck screws. They are around the same cost for a box. Drywall screws do snap off too easy. Deck screws are much stronger. The heads can strip out but they don't break. Use them sometimes to hold boxes too.

300-6 Protection against corrosian
Includes support hardware shall be suitable for the enviroment in which they are to be installed.

Drywall screws have a black coating but they do rust. They are not made for outside. Maybe rust thru outside?

To hold up the mast drywall screws are way too weak. Do like Dave said and use lag bolts. Or some other 5/16 or 3/8 fastener depending on surface. Make sure the lags and washers are galvinized. Not that I think they will rust thru. It's just beter to do it in a way that the inspector has nothing bad to say about it. Don't want to do it twice. Besides you don't want there to be rust stains on the house years later because you used the wrong washer.

And don't use drywall screws for fan boxes.

For panels you could also use a #10 anchor swrew (without the plastic anchor). They are tough screws.

An onerhead service should cost you a few bucks in hardware to do a good job.

Tom

#92895 04/15/05 09:35 PM
Joined: Feb 2002
Posts: 375
G
Member
sid123456 ---

I believe the inspector is in error.

I don't recall what the strength of drywall screws is but, I expect it is sufficient. You might ask the inspector what load the electrical components need to be desinged to support. I expect you will then have the oportunity to laugh at him.

#92896 04/16/05 07:10 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Sid you said;

Quote
I screwed up my panel to the studs and mast up the wall.

This leads me to believe you are talking about an installation exposed to weather.

In my opinion that would be a violation of 300.6

Quote
300.6 Protection Against Corrosion.
Metal raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the environment in which they are to be installed.

If the drywall screws where not of the galvanized type I think the inspector was correct.

In my opinion the above is clear cut.

The use of drywall screws (even if galvanized) to support a mast is more subject to interpretation.

There are two code articles I can think of relating to mast and this question.

Quote
230.28 Service Masts as Supports.
Where a service mast is used for the support of service-drop conductors, it shall be of adequate strength or be supported by braces or guys to withstand safely the strain imposed by the service drop. Where raceway-type service masts are used, all raceway fittings shall be identified for use with service masts. Only power service-drop conductors shall be permitted to be attached to a service mast.

And

Quote
344.30 Securing and Supporting.
RMC shall be installed as a complete system as provided in Article 300 and shall be securely fastened in place and supported in accordance with 344.30(A) and (B).

The typical drywall screws that come to my mind are fine threaded bugle head #6s.

In my opinion they are to brittle and to thin to be strong enough for a mast, also the threads are to fine to get a good grip on the lumber.

For a mast I would use at least 1/4" galvanized lags.

All this is really up to the inspector to determine the suitable of the fastener for the particular application.

I sometimes use drywall screws to mount 4" square boxes this is a far cry from a mast and I would rather use #10 screws for almost any small equipment.

Bob



[This message has been edited by iwire (edited 04-16-2005).]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#92897 04/16/05 02:18 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
I too am a big fan of the #10 Galv/zink hex heads, for most everything, and lags for panels and such.


Mark Heller
"Well - I oughta....." -Jackie Gleason
#92898 04/18/05 05:31 PM
Joined: Jun 2003
Posts: 1,143
D
Member
I can understand the AHJ if his concern was corrosion.

Heard of an inspector failing to pass a job where the sprakies had used drywall screws to secure the boxes. He insisted they install using wood screws.

It was decided that, even though local and national Code didn't specify, it would be easier in the long run to not fight the AHJ, and thus guarantee fewer hassles on future jobs.

#92899 04/18/05 07:17 PM
Joined: Jan 2005
Posts: 5,316
Cat Servant
Member
I don't see a violation, and I believe the inspector is in error.
That said, I generally do not use sheetrock screws for this application- even though I have many such screws on my truck.
I like to use the screws made by Simpson for their metal brackets. They are of a similar thread and point to sheetrock screws, with two differences:
-they are slightly heavier, at #8 gage; and,
- they have a wider "washer" head, which won't pull through the holes in mounting straps.

For heavier applications, Simpson has also re-invented the lag bolt, giving it a hex (rather than square) head and a sharper point.

I know I sound like an ad....please forgive me....they just happen to make something I like :-)

#92900 04/18/05 07:21 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Quote
I don't see a violation, and I believe the inspector is in error.

What about 300.6?

Maybe in Reno screws don't rust out but they sure do here in NE. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#92901 04/18/05 08:22 PM
Joined: Mar 2004
Posts: 98
O
Member

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