Metal guards on stud for wiring

[andyvh1959]

For the wiring in my detached garage, i ran the wires through the 2x6 wall studs. I drilled holes for the wires at least 1" into the wall from the inner face of the wall studs. Electrical inspector for Green Bay WI came by and he only noted a few thing to correct:
1. 2nd ground rod 6' from the one I have routed through the slab.
2. Wiring staples within 8" of the boxes

But he did not add that I should have metal straps on the stud guarding the area where the wires pass through the studs. I routed the wires through the wall less than 8" above the boxes purposely to reduce the likelyhood of a nail or screw into the stud hitting a wire. Does the NEC require metal guards on the studs? Or is it a regional wiring specification? I added the 2nd ground rod and stapled the wires above the boxes as noted.

 

[pattenp]

Bored holes closer than 1.25" to the nailing surface needs protection plates.

 

[rburke65]

Inspection passed, but they should have some type of nail guard over the stud area.

 

[Jim greengo]

I normally try and drill holes through center of studs.
I'd nail gaurd them.

 

[wyliesdiesels]

For the wiring in my detached garage, i ran the wires through the 2x6 wall studs. I drilled holes for the wires at least 1" into the wall from the inner face of the wall studs. Electrical inspector for Green Bay WI came by and he only noted a few thing to correct:

1. 2nd ground rod 6' from the one I have routed through the slab.
2. Wiring staples within 8" of the boxes

But he did not add that I should have metal straps on the stud guarding the area where the wires pass through the studs. I routed the wires through the wall less than 8" above the boxes purposely to reduce the likely hood of a nail or screw into the stud hitting a wire. Does the NEC require metal guards on the studs? Or is it a regional wiring specification? I added the 2nd ground rod and stapled the wires above the boxes as noted.

shouldve drilled holes closer to center at say 1 1/2" or 1 3/4" on a 2x4 but you have 2x6s so you couldve drilled them at 2 1/2" and not have to worry about nail plates.

also, code is staple within 12" of box...

 

[andyvh1959]

Right on the staples at 12". I just did added them within 8". The holes through the studs are actually about 1-1/4" in from the stud face. So the plates are or are not required by NEC? I may add the plates anyway.

 

[wyliesdiesels]

if the holes are closer than 1.25" then they need plates. I like to put them on even at 1.25" if someone else is doing the drywall and ends up using longer screws than usual

 

[Norcal]

shouldve drilled holes closer to center at say 1 1/2" or 1 3/4" on a 2x4 but you have 2x6s so you couldve drilled them at 2 1/2" and no worry about nail plates.

also, code is staple within 12" of box...

Single gang boxes w/ NM cable W/O clamps need to be stapled within 8".

 

[nadogail]

IMHO, the cost of Nail Plates is less than the cost of going back in to fix something where the plate was left out.

 

[Terry D]

Even when running wires down a stud, the 1 1/4 rule needs to be followed. On a 2x4 you can get 2 wires next to each other and be ok. Anything more than 2 wires, you need to use stack-its. Naturally on a 2x6 stud, you can have more wires stapled on the surface before violating the rule

https://www.amazon.com/dp/B001AWP7MI/?tag=atomicindus08-20

 

[Jim greengo]

shouldve drilled holes closer to center at say 1 1/2" or 1 3/4" on a 2x4 but you have 2x6s so you couldve drilled them at 2 1/2" and no worry about nail plates.

also, code is staple within 12" of box...

 

[wyliesdiesels]

Single gang boxes w/ NM cable W/O clamps need to be stapled within 8".

hmmm i couldve sworn it was 12"

 

[Norcal]

hmmm i couldve sworn it was 12"

Everything else other than the plastic single gang nail on is 12"

 

[wyliesdiesels]

Everything else other than the plastic single gang nail on is 12"

so a plastic double gang nail-on is 12"?

 

[sparky 1971]

Single gang boxes w/ NM cable W/O clamps need to be stapled within 8".

How about a code reference for that? I am not saying it isn't there, but I can't find it and have never heard of such a thing. All I can come up with is 334.30. This is from the 2017 NEC.

334.30 Securing and Supporting. Nonmetallic-sheathed cable shall be supported and secured by staples; cable ties listed and identified for securement and support; or straps, hangers, or similar fittings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (4 ½ ft) and within 300 mm (12 in.) of every cable entry into enclosures such as outlet boxes, junction boxes, cabinets, or fittings. Flat cables shall not be stapled on edge.

 

[Innovate1]

Not sure where in the code it is but I took a test for a homeowners permit last year and it is 8" from the box if it doesn't have a clamp (like the plastic boxes that just have a hole) and 12" if it has a clamp.

How about this:
551.47 Wiring Methods.
(J) Nonmetallic Box Without Cable Clamps. Nonmetallic sheathed
cables shall be secured and supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps.

Or 314.17 C - requires nonmetalic sheathed cable be secured to the box. There is an exception for a single gang without clamps if the cable is secured within 8".

 

[sparky 1971]

Not sure where in the code it is but I took a test for a homeowners permit last year and it is 8" from the box if it doesn't have a clamp (like the plastic boxes that just have a hole) and 12" if it has a clamp.

How about this:
551.47 Wiring Methods.
(J) Nonmetallic Box Without Cable Clamps. Nonmetallic sheathed
cables shall be secured and supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps.

Or 314.14 C - requires nonmetalic sheathed cable be secured to the box. There is an exception for a single gang without clamps if the cable is secured within 8".

I'll be damned. I wish the code panel would group all the "like" topics together. I have never measured the staples, but would guess the first is 8-10". Always told the new guy to make sure it's within a foot. Six hours of CEU on Tuesday, if can stay awake and think of it, I will ask the instructor for some insight as to the reasoning.

 

[Innovate1]

BTW, when I gave both the 8" and 12" details on my test (written out answer not multiple choice) the code department guy said I was the only one that ever gave the full answer. Not sure where I first learned about it when studying.

What's really strange is they also require courtesy loops and those aren't counted as part of the distance, at least how I read it.

 

[Norcal]

Thanks for adding the code reference, I was offline for a few hours so it was done & over before getting back.

 

[Pingel85]

551 is recreational vehicles so that doesn’t really apply.

Also, my 2017 doesn’t have a 314.14......What am I missing?

 

[Innovate1]

551 is recreational vehicles so that doesn’t really apply.

Also, my 2017 doesn’t have a 314.14......What am I missing?

Might be 314.17(C) exception. I don't have an easy way to check right now but I see several other sites refer to that.

 

[Taco Truck]

The 314.17(B)(2) exception in my 2020 NEC states that 2.5"X4" nonmetallic boxes with knockouts not less than 1/4" in diameter don't need to be supported in the box if they're supported outside of the box within eight inches. Where the confusion comes from, I think, is that people assume that the tabs in plastic boxes are a knockout which requires support at eight inches. I don't interpret it that way. I think the tabs themselves count as support in the box and you only have to support the NM if you've actually removed the tab.

When I was a first year apprentice we were told to staple the NM no further than eight inches just so there was no potential for issues during inspections. What happens is people are given instructions like this and tell the next person who tells the next person and before you know it people just start thinking that romex needs to always be supported at eight inches when it's in a plastic box.

 

[sparky 1971]

Might be 314.17(C) exception. I don't have an easy way to check right now but I see several other sites refer to that.

314.17(c) is it. Now...Why can't the geniuses that make up the cmp put that in 334.30? Maybe it would make too much sense to put it in the secuement of nm cable article.

 

[Taco Truck]

314.17(c) is it. Now...Why can't the geniuses that make up the cmp put that in 334.30? Maybe it would make too much sense to put it in the secuement of nm cable article.

Just a heads up for when Iowa adopts the 2020 code, but that's not the code reference in the 2020 edition. It's 314.17(B)(2).

 

[sparky 1971]

Just a heads up for when Iowa adopts the 2020 code, but that's not the code reference in the 2020 edition. It's 314.17(B)(2).

Thanks. Jan. 1, 2021 it goes into effect. I finally have the update class tomorrow. The last one got canceled for the 'Rona. Not too concerned about the cable stapling though, I have been installing them the same way for 26 years. Apparently, it's either close enough or the inspectors don't care.

 

[andyvh1959]

Wow, when I posted this didn't think it'd generate this much discussion. Just goes to show how much a lowly homeowner doesn't know of the NEC, and how easy it is to screw up. Sure helps not having inspection issues later. So for the record on my wiring:
1. Holes through the studs are at 1.25" from the inner face, I didn't know any better
2. I have plastic boxes without the clamps, so I stapled the cables within 8" of the boxes
3. I am adding the wire shields onto the studs over the area where the wires pass

Thanks for all the input, especially from all the experts on here. Goes to show there is a LOT to know than just where to hook up the black, white and ground. Electrical inspector is coming this Friday for the followup inspection from his 1st review. I already installed the 2nd ground rod and I'll have the ground line connected to the ground rods and into the sub panel ground bar. It'll be interesting to see what he says.

 

[cmandp]

Don't forgot NM needs to be supported every 4-1/2' (I think it's 4-1/2' anyway) along the run. And going through framing counts as supported.

I learned while doing things in the 1950s addition to our house. They framed the part I was working on with 2X3s. So you can never be the required 1.25" from the surface of the stud. Used a lot of plates in there.

Also ran into this in our attic going down through the wall plate that's over a doubled up joist. Have to drill near the edge of the plate to not hit the meat of the joist.

 

[reader2580]

My brother and my father wired my brother's new house. He failed the rough-in inspection because he didn't use the clamps in the plastic boxes that were closest to the the stud. (Or maybe it was furthest from the stud) The inspector made him put large nailing plates behind every box. The big ones like a plumber might use. He had to go to multiple stores to get enough.

 

[Norcal]

The plumbing safety plates do not meet the requirements in the NEC as they are thinner then the safety plates used for electrical.

 

[wyliesdiesels]

The home depots out here carry 3 types- 20ga, 16ga, and 14ga

 

[Taco Truck]

Not too concerned about the cable stapling though, I have been installing them the same way for 26 years. Apparently, it's either close enough or the inspectors don't care.

For sure. It definitely falls into the "is this really ******* necessary" category for me, and I think reasonable inspectors probably feel the same way.

 

[reader2580]

The plumbing safety plates do not meet the requirements in the NEC as they are thinner then the safety plates used for electrical.

I saw the plates he used and they were very thick. He said he got them in the plumbing area. The second rough-in inspection passed so the inspector was apparently okay with them.

 

[rburke65]

TacoTruck.....I second that !

 

[checkthisout]

The reason for 8" and 12" is single-gang boxes are the only boxes that are rated for use with no retention where the cable enters the box hence the requirement for 8".

Single-gang and above all have clamps/retention where the wire enters the box hence the 12"

 

[spudley]

Where the confusion comes from, I think, is that people assume that the tabs in plastic boxes are a knockout which requires support at eight inches. I don't interpret it that way. I think the tabs themselves count as support in the box and you only have to support the NM if you've actually removed the tab.

Hmmm...So you believe the itsy bitsy tabs holding the knockouts in place really act as a clamp securing wire to the single gang box?

I'll buy in on the double gangs with the spring action type but no way on single gangs.

Staples are cheap.

 

[checkthisout]

The 314.17(B)(2) exception in my 2020 NEC states that 2.5"X4" nonmetallic boxes with knockouts not less than 1/4" in diameter don't need to be supported in the box if they're supported outside of the box within eight inches. Where the confusion comes from, I think, is that people assume that the tabs in plastic boxes are a knockout which requires support at eight inches. I don't interpret it that way. I think the tabs themselves count as support in the box and you only have to support the NM if you've actually removed the tab.

When I was a first year apprentice we were told to staple the NM no further than eight inches just so there was no potential for issues during inspections. What happens is people are given instructions like this and tell the next person who tells the next person and before you know it people just start thinking that romex needs to always be supported at eight inches when it's in a plastic box.

Do they make single-gang NEW WORK boxes with cable clamps?

 

[Taco Truck]

Hmmm...So you believe the itsy bitsy tabs holding the knockouts in place really act as a clamp securing wire to the single gang box?

I'll buy in on the double gangs with the spring action type but no way on single gangs.

Staples are cheap.

Yes. Ever tired to pull romex out of a box with those tabs? Let me know how it works for you.

What are you going on about? I'm aware staples are cheap. I'm not saying not to use them. I'm just pointing out why I think the code us written the way it is.

 

[andyvh1959]

Electrical inspector came by yesterday and I'm approved! He checked/confirmed my 2nd ground rod installation and ground cable routing to the ground bar in the sub-panel. I had wired in the service cable to the main lug and neutral lug, all good there. Showed him I added the cable staples and wire shields. Even that I had taken off the OSB I had already temporarily mounted on three walls to add the staples and shields.

For the red, black and white 2awg THHN cables I routed to the lugs in the sub panel, is there an actual torque value for the clamp screws? Or just tighten them as much as possible?

We actually spent more time discussing my off grid solar system for LED shop lighting, workbench lighting and motorcycles charging. He was pleased I had planned in a fused, switchable combiner box for the four panels feeding the charge controller. He said he has inspected many systems wired into the grid, but not a stand alone 12v system like mine. We did discuss some notation on or in my garage to alert fire/emergency personnel that the 12v solar system is always live. My system will use four 12 deep cycle batteries wired parallel, so I'm well below the 96v range that requires an auto shut off. I also have a separate ground rod for the system and will ground the panel mount system as well.

 

[wyliesdiesels]

Electrical inspector came by yesterday and I'm approved! He checked/confirmed my 2nd ground rod installation and ground cable routing to the ground bar in the sub-panel. I had wired in the service cable to the main lug and neutral lug, all good there. Showed him I added the cable staples and wire shields. Even that I had taken off the OSB I had already temporarily mounted on three walls to add the staples and shields.

For the red, black and white 2awg THHN cables I routed to the lugs in the sub panel, is there an actual torque value for the clamp screws? Or just tighten them as much as possible?

We actually spent more time discussing my off grid solar system for LED shop lighting, workbench lighting and motorcycles charging. He was pleased I had planned in a fused, switchable combiner box for the four panels feeding the charge controller. He said he has inspected many systems wired into the grid, but not a stand alone 12v system like mine. We did discuss some notation on or in my garage to alert fire/emergency personnel that the 12v solar system is always live. My system will use four 12 deep cycle batteries wired parallel, so I'm well below the 96v range that requires an auto shut off. I also have a separate ground rod for the system and will ground the panel mount system as well.

Yes there is a value and it should be listed on the panel label or documentstion that came with the panel.

 

[andyvh1959]

Found this on the Schneider (Square D) page:

https://www.se.com/us/en/faqs/FA128927/

Gotta get out my inch-pound torque wrench and confirm the lug values.

My take is its more intended to insure people tighten them enough, and not assume that just snug is good. In Wisconsin we have no tremors or earthquakes. But in other locales enough shaking could occur to cause a connection to fail and arc if the lug wasn't tight enough to begin with. Do the lug screws loosen over time due to wire strand settling?