Any Tips on Lining Up a KO hole

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Old 03-28-14, 09:53 AM
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Any Tips on Lining Up a KO hole

Ordered a large pull box that will sit right underneath a transfer switch.
Plan to mount them via close nipple. Will be utilizing the 1" KO already on the transfer switch.

So just short of measure twice, cut once

Do I simply line up the hole, and mark the current KO onto the pull box top


Then Measure the middle of that drawn circle - create my hole for the KO stud and Hope when all said and done, they line up exactly how I wanted them . I know there is some slop/wiggle room in this- about 1/8" of tolerance.

Any other suggestions you can offer to this weekend warrior.
 
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Old 03-28-14, 10:09 AM
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I would not sweat it too much. The knockout holes are generally larger than the fitting so there will be some wiggle room at each box. Left to right is pretty easy to line up but if you get off in/out you can shim behind the enclosure when you screw it to the wall.
 
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Old 03-28-14, 11:20 AM
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Do I simply line up the hole, and mark the current KO onto the pull box top
That would be it. Mount the transfer switch, knock out the KO and hold the pull box in place directly under the transfer switch. Trace thru the 1" KO with a sharpie right onto the pull box.

You can do the same thing by laying both items flat on their backs on a workbench. They would be at the same mounting level and you'd trace thru the transfer switch onto the pull box.
 
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Old 03-28-14, 01:49 PM
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Drill the hole for the punch stud in the pull box. Stack the pull box on the panel and use the KO to line up the punch in the KO.
 
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Old 03-29-14, 06:32 AM
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BTW, pros/cons of coupling this together

Option A: 2 Chase Nipples and a Ridgid Coupler
Option B: Locknuts, Short Nipple, Bushing

B - being the more common way I suppose ?
 
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Old 03-29-14, 06:59 AM
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Either way is acceptable.
 
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Old 03-29-14, 07:15 AM
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Close nipples do not need a coupling, just 4 locknuts.
 

Last edited by pcboss; 03-29-14 at 07:40 AM.
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Old 03-29-14, 07:27 AM
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Close or short nipples need 4 lock nuts. Two on each end.

Chase Nipple need a threaded coupling if you use two:

[ATTACH=CONFIG]29145[/ATTACH]
 
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Old 03-29-14, 07:33 AM
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Locknut Still Required on the Inside if I go the Chase Nipple Route ?
 
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Old 03-29-14, 07:42 AM
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With the chase nipple the panels are touching. All you need is one locknut.
 
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Old 03-29-14, 07:43 AM
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No. Just make it tight on the coupling. They also make long chase nipples if you can not find a short rigid coupling.

Yes, if if the panels are tight together, you only need one chase nipple, one lock nut, and a bushing if your wire is #4 or larger.
 
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Old 03-29-14, 09:46 AM
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Two chase nipples plus a coupling makes a very clean-looking install, plus it gets the panels close together but far enough apart to preserve the function of the two doors and covers.
 
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Old 03-29-14, 10:36 AM
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I was thinking about the covel panel on the pull box . With the 2 mated tight, it might not be so fun taking/putting it on.

Locknut required between coupler/exterior side of panel if I am using a chase nipple ?
 
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Old 03-29-14, 11:41 AM
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Locknut required between coupler/exterior side of panel if I am using a chase nipple?
Originally Posted by Tolyn Ironhand
No. Just make it tight on the coupling.
. .
 
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Old 03-29-14, 11:52 AM
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The can "extend" the exact center of the 1" K.O. to the pull-box with a plumb-line.
 
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Old 03-29-14, 03:29 PM
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Thank you all. Started the 1st step of the install

Ran some Backboard, shot some nails into the crete - and waiting for the PL Premium adhesive to setup...
 
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Old 03-29-14, 08:08 PM
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Two chase nipples plus a coupling makes a very clean-looking install, plus it gets the panels close together but far enough apart to preserve the function of the two doors and covers.
Yes, it makes a clean good looking installation. I've seen this done twice on larger panels, one was a 800 amp generator panel, it looked great, no problems. The second time was on a 400 amp installtion and the inspector wouldn't pass it. The rigid coupling, according to U.L. Listing, is to be used to join two lengths of rigid conduit and isn't listed to be used as an adapter for a chase nipple.
 
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Old 03-30-14, 06:56 AM
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I have had the same experience using the coupling,really not sure what the advantage is to using the coupling in the first place accept for saving on a couple of locknuts and bushings.
 
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Old 03-30-14, 07:16 AM
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It appears to me that the only advantage is cosmetic. The disadvantage I see is that locknuts, when properly tightened, actually bite into the metal box through any paint, but the chase nipples and rigid coupling just press against the metal box. The inspector had a valid point.
 
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Old 03-30-14, 08:19 AM
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The disadvantage I see is that locknuts, when properly tightened, actually bite into the metal box through any paint, but the chase nipples and rigid coupling just press against the metal box. The inspector had a valid point.
I would have suggested to just bond around the nipples then.
 
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Old 03-31-14, 11:48 AM
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Curiosity intrigues me. Where does CODE specify when you need to use a INSULATED chase nipple versus non insulated. The Flared profile of a chase nipple seems to be sufficient enough for all intended wires/abrasion issues ?
 
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Old 03-31-14, 06:18 PM
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There is nobody that makes an insulated chase nipple AFAIKO. A chase nipple is for exactly what you describe, to protect the wires from abrasion on a sharp edge. Whether it is a plastic one or a metal one will only depend on the wiring method used.
 
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Old 03-31-14, 06:36 PM
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Off the top of my head, T&B, Arlington and Bridgeport most def. do make a insulated variant.
 
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Old 03-31-14, 06:44 PM
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I have never seen, nor heard of an insulated nipple.
 
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Old 03-31-14, 06:51 PM
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One of these is what I was referring to

 
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Old 03-31-14, 06:53 PM
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That's not considered an insulated nipple. It just a bushing to minimize sharp edges.
 
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Old 03-31-14, 07:03 PM
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It's not a separate bushing you insert though. It comes WITH or Without.

I'm not sure the part/model # WITH, is the OD of the chase nipple actually larger, so that the ID of the overall with the lined Bushing/Insulated is the same as with a Chase Nipple Without.

Hence, bearing the question that sparked this, does code Dictate when you need to use a Insulated chase nipple/bushing rather than a regular ~unlined~ version.

I guess the same Question would apply to flex connectors. I've used and seen both insulted and non insulated Flex Connectors. I see the benefits of the lined for the throat of the fitting, but technically, it's nice and smooth anyways.
 
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Old 03-31-14, 07:04 PM
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Thanks for the picture. .
 
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Old 03-31-14, 08:36 PM
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