Knockout on a pre-stamped KO on Panel
#1
03-25-14, 04:41 PM
Knockout on a pre-stamped KO on Panel
I'm leaning on making a 1" KO in a area of the panel where it has a 2" or so pre stamped KO.
Is this OK to do ?
There is not other area I can see that will accomodate the 1" conduit I plan to run to the panel
Is this OK to do ?
There is not other area I can see that will accomodate the 1" conduit I plan to run to the panel
#2
03-25-14, 04:51 PM
How do you plan on punching this hole? A drill will cause the existing KO to come loose. About the only safe way to do it is with a punch set. You can do that anywhere on the box, basically, not just on the KO's.
#3
03-25-14, 04:59 PM
You can, but I'm pretty sure the code requires using a grounding bushing on the connector in the panel. Pre stamped holes aren't considered to have continuity for grounding.
#6
03-25-14, 05:11 PM
I was just looking in my code book, but it's 2008 and I don't see it mentioned. I think the 2011 changed for using concentric and eccentric KOs. I've had to use bushings on jobs, but I don't remember what kind of KO's they were. Either one or the other, or all types of KOs need grounding bushings now.
#7
03-25-14, 05:40 PM
Group Moderator
Usually only the incoming service requires a bonding bushing. Technically it's required on a concentric knock out only but I use them on all incoming piped service connections.
If you press too hard you may end up knocking out that 2" or so KO and then you could use donuts(reducing washers) to fill the hole.
If you press too hard you may end up knocking out that 2" or so KO and then you could use donuts(reducing washers) to fill the hole.
#8
03-25-14, 05:51 PM
The reducing washer is a good idea. You may be right about the feed being whats actually required for the bushing. Some of or jobs are specced to put bushings on all the pipes using KOs coming into a panel. That might be what I'm thinking about.
#9
03-25-14, 05:54 PM
Group Moderator
Usually connectors like romex, MC or BX connectors are too short to put bushings on but any pipe run coming into the panel should have a bushing on it. Just a plastic bushing.... not a bonding bushing.
#11
03-25-14, 06:46 PM
Member
I was just looking in my code book, but it's 2008 and I don't see it mentioned. I think the 2011 changed for using concentric and eccentric KOs. I've had to use bushings on jobs, but I don't remember what kind of KO's they were. Either one or the other, or all types of KOs need grounding bushings now.
#12
03-25-14, 07:11 PM
Forum Topic Moderator
The code requires the bushing when the coonector does not provide a smooth edge or when conductors #4 and larger are used.
#13
03-25-14, 09:27 PM
The area is the only area where I can make the 1" KO.
