# electrical knock out box holes **URL:** \ **Category:** Factual Questions\ **Created:** [January 22, 2017, 8:12pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869 "2017-01-22T20:12:04Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [January 22, 2017, 8:12pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/1 "2017-01-22T20:12:04Z")
hello, in the electrical boxes/ knock out boxes there are lots of holes some larger than the others what are they all for? I googled but didnt come up with anything. I don’t mean the ones that you take out to put wires through, I mean the small one on the sides other than the ground and attachment screws virtually yours Virtually Yours ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [January 22, 2017, 8:15pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/2 "2017-01-22T20:15:05Z")
> [@virtually\_yours](#): > > hello, in the electrical boxes/ knock out boxes there are lots of holes some larger than the others what are they all for? I googled but didnt come up with anything. > I don’t mean the ones that you take out to put wires through, I mean the small one on the sides other than the ground and attachment screws Have you got a picture you can share? I’m not aware of any knockouts on an electrical box that would _not_ be for wires. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [January 22, 2017, 8:39pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/3 "2017-01-22T20:39:04Z")
Perhaps the heavy ground wire … 6 gauge I think … make sure you use a [romex clamp](https://s3.amazonaws.com/cesco-content/unilog/Batch3/018997/625313-ProductImageURL.jpg) to run the wires into the box … ---
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [January 22, 2017, 8:56pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/4 "2017-01-22T20:56:12Z")
> [@friedo](#): > > Have you got a picture you can share? I’m not aware of any knockouts on an electrical box that would _not_ be for wires. hi, not talking about the knockouts, I am talking about the little screw sized holes all around it. opps i think i found out what they are for, to attach a side bracket. saw it on this pic [http://www.garvinindustries.com/electrical-junction-boxes/4-square-junction-boxes/1-1-4-and-1-1-2-deep/52151-3-4ab](http://www.garvinindustries.com/electrical-junction-boxes/4-square-junction-boxes/1-1-4-and-1-1-2-deep/52151-3-4ab) ---
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [January 22, 2017, 8:58pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/5 "2017-01-22T20:58:04Z")
here are a few other examples [http://www.garvinindustries.com/electrical-junction-boxes/4-square-junction-boxes/1-1-4-and-1-1-2-deep](http://www.garvinindustries.com/electrical-junction-boxes/4-square-junction-boxes/1-1-4-and-1-1-2-deep) ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [January 22, 2017, 9:23pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/6 "2017-01-22T21:23:04Z")
The little screw sized holes are for actual screws to mount the box to the wall. ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [January 22, 2017, 11:03pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/7 "2017-01-22T23:03:50Z")
You’ll find they are for fixings for the earth tags on steel wire armoured cable glands ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [January 22, 2017, 11:25pm UTC](https://boards.straightdope.com/t/electrical-knock-out-box-holes/777869/8 "2017-01-22T23:25:56Z")
Big ones for cable, little ones for multiple options for attaching the box with screws to something solid.