Breaker box ain't got no holes!?

[jack]

I am installing a 120v water heater in a 208/120 breaker box. Oddly, there are no knockouts. Is that common in 208/120v?

I see three options; your advice on their legality would be appreciated.

1) I can cut a hole with a hole saw. Not a pleasant chore, but possible. 2) There is an outlet in a box just below the breaker box, connected to it by a 1/2" conduit. I could connect my MC cable to the outlet box and run the wires into the breaker box by the 1/2" conduit. I presume 1/2" conduit can take two sets of #12 cable. 3) I can run my circuit to the outlet box and attach it to the wires that feed the outlet. The outlet is only used for a radio and the water heater is only 13a, so there should be plenty of capacity.

[Colbyt]

More than one wire can go through a single knockout.

If your wire will not fit through an existing one, relocate one of the 110v to create space.

This option is 100% legal. The others I have doubts about.

[jack]

All the existing holes have conduit connected to them, so they aren't available. It might be legal, but it isn't possible.

[gfretwell]

It is common for industrial equipment to come without preformed KOs. Industrial electricians have KO punches and poke a hole where they need one. You can get the wrench powered ones at a good home store. Drill a 3/8" hole, assemble the cutter and die on each side and tighten it up and you cut a clean hole.

[RBM]

A 7/8" hole saw cuts you a 1/2" knockout. Drill a few for the future

[aemeijers]

What the other guy said about a hole punch (Greenlee?). Makes a much nicer hole, and little or no debris inside, and no warping of the panel.

-- aem sends...

[RBM]

Big difference in price between a 7/8" hole saw and a greenlee punch, besides, if he has a panel with no KO's in it, it's a commercial panel, it ain't gonna warp

[Colbyt]

I missed that part of the post. Sorry.

The other posters have good suggestions.

I would have to wonder why everything is in conduit. Is the a commercial building? Or a Condo type project?

Conduit may be a requirement for certain structures and locations.

Are they all in use? Sometimes when I have to cut open a wall to pull a wire I add some empty conduit sections to the panel box for future use. I cap both ends to prevent critter entry.

Try a rental center for the proper tool. It sounds expensive.

[S. Barker]

How did you get the water heater IN the breaker box?

s

[HeyBub]

Why do you say that? A metal-cutting hole-saw should do the job in less than two minutes.

[Pete C.]

The much maligned Harbor Freight has a manual KO punch set rather cheap that would probably do the job. They also have a hydraulic driver available.

There is also the option of the Greenlee KO sized step bit, which is what I use for the small number of times I need to make holes in pull boxes and whatnot.

[dpb]

Pete C. wrote: ...

If the box steel isn't harder than the punch... :)

HF -- ya pays ya money and takes ya chances...

--

[gfretwell]

A Greenlee punch is $30 or so if you shop around and it will last a lifetime. Over the years I have managed to collect several sizes and they all still work fine.

[dpb]

[e-mail] wrote: ...

Agreed...

--

[Pete C.]

Yep, which is why having a HF retail store nearby where you can see the items in person is a huge benefit. There are a number of gems in their lineup, as well as many more perfectly serviceable for home shop use items.

[Pete C.]

Yes, but the HF set is half that. They may not last a lifetime in pro use however.

[dpb]

Pete C. wrote: ...

The question w/ HF is will they last a single use??? :)

IME it's been a crapshoot...some stuff is amazingly good for the price; some is pure junk. The problem is there's almost no way to tell a priori...

Since there's no local outlet, I've pretty much given them. Doesn't mean anybody else needs to take the advice, I was simply making a (mostly) lighthearted aside...

--

[dpb]

Pete C. wrote: ...

Wish I'd seen this comment before the other...is there an echo here? :)

--

[Colbyt]

For the $15 it is sure to make one or two holes.

I retract the rental suggestion. This is the way to go.

Colbyt

[RBM]

I still don't know why. To use a 1/2" KO greenlee punch, you have to drill a hole practically that large to fit the bolt through. You may as well use a

7/8" hole saw. Drill once and you're done... and it's cheaper