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What You’re Allowed to Drill Through in a Wood Frame Setting

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What You’re Allowed to Drill Through for Wires in a Wood Frame Setting

What We Cover in this Article:

  • What You’re Allowed to Drill Through in a Wood Frame Setting

With this post’s popularity, I have written other how to drill holes for wires articles.


You may think, “Oh, this is a silly post”..

But believe me! – I’ve seen this stuff first hand when co-workers drill through or cut the wrong thing.

So, I’m going to keep this short and brief, but please do not take this lightly.

By drilling into/cutting the wrong thing, it can open a huge can of worms, get an engineer involved, be very costly, and be a really embarrassing moment for you.

Please note, this is my disclaimer:

I will not be held liable for things you can and cannot drill through, the outcome or financial burden of your situation. Please make sure to ask your boss/site general before proceeding with drilling/cutting.

Let’s first start with what we can drill through.


When pulling our wire as electricians, most things are pretty safe to drill through; it’s mostly structural beams and trusses which are big no-no’s.

But your standard 2×4 and 2×6 stud walls which we mount our boxes on are usually safe! (Always check the other side of the stud before drilling! There might be wires!)

Here’s a picture of a safe 2×4 wall to drill through:

An example of a 2x4 wall in a condo building in rough construction.
An example of a 2×4 wall in a condo building in rough construction, which we mount our electrical device boxes on. These are usually very safe to drill through, just make sure to check the other side of the 2×4 before drilling!

I know it may be hard to tell, but here’s a 2×6 wall:

A 2x6 Wall which a Range or Dryer Electrical Box is mounted on.
A 2×6 wood framed wall in rough construction. Notice the electrical box has much more space behind it. (The box is a 4-11/16-inch box.. other known as a Range (Oven) or Dryer Box.. must be supported on two sides!)

Now, these 2×4 and 2×6 walls also have top and bottom plates. These are also safe to drill through if we need to pull our wires down to a switch or into the basement.

On a side note, NEVER run your wires on a top plate. When people drill, they usually do not double check a top plate because nothing should be there. This is a serious no-no.

But with bottom plates I usually walk downstairs and take a quick peak just to make sure no wires or other materials are in the way of your drilling.

Showing the Top Plate of a 2x4 Wall which electricians should never staple their wires to!
This is an example of a top plate which we electricians can drill through to pull our wires down to light switches, thermostats, or plugs for example. (NEVER staple your wires on the top or bottom of a top plate.. no one can see them, and can potentially drill through and damage your wires!)


Remember, if you’re unsure, ask before you drill!

Here’s some examples of what you cannot drill into:

Structural Beams / Load Bearing Support Beams:

Structural Support Beam (Laminated Beam.. or LVL Beam)
This is a structural support beam which is load-bearing. Do not drill through these! These are sometimes different colors, and can be termed as LVL (Laminated veneer lumber), or Engineered Support Beam. (The odd time an engineer is consulted regarding drilling through, which they will tell where, and what size of bit to use!)

Sometimes these structural beams are yellow, but sometimes they aren’t!

Support beams are usually pretty obvious because the type of wood looks different and is installed in such a way that it is a crucial part of the building to hold up weight.

Besides the color of these structural beams, their height is often quite big, too; like 14″ in height for example!

I personally suggest you don’t drill through these beams ever. I have been on a site where it’s been approved to drill a small hole in this structural beam, but it’s important to make sure all the paper work is in place and everything is signed.

I’d rather find an alternative path around a support beam myself, even if it requires more wire.

On a side note – I was once on a job where someone sawzalled just a little bit of the floor joists just to get a light box to fit in a better place. (This was an embarrassing moment for that person and involved phone calls from the higher ups.)


Roof Truss Example on Top Floor of Building
Trusses are only on the top floor of a building. NEVER drill through these. As an electrician, our top floor is typically our fastest because we can simply pull our wires on top of the trusses and staple on top of them, rather than having to drill all of our holes!
Truss Example in a Condo
Notice how wires can be stapled to the side of a truss. We can also run our wires from truss to truss, but if the height is more than 3 feet, we need to use a RUNNNG BOARD (which you can actually see in the image on top of the trusses!) DO NOT DRILL into a truss!

Trusses are only on the top floor of a building. They are what the actual roof attaches to.

NEVER drill through these.

As an electrician, we can pull our wire on top of trusses and staple on top of them.

If a truss becomes larger than 3 feet in height, electricians are required to use a running board to staple their wires to for support. (Often some scrap 2×4 or 2×6 is used to go from rafter to rafter). This is so no one will step on the wires between the trusses if they need to go up there when it is dark.

A fun fact: the top floor is actually your fastest floor for rough-in as an electrician because the amount of holes you have to drill is dramatically reduced because you can simply pull your wires on top of the trusses instead of having to drill holes like we do on lower floors or basements!


And so there you have it.

Those are your most common things you’ll see in a wood frame setting, from my experience.

If you’re ever unsure, just ask. It’s really as simple as that.

And, don’t forget, you’ll also want to make sure you drill your holes level for your wires, so you can be efficient, not burn the wires, and have a VERY professional and clean look.

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