How would you do this?

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bjp_ne_elec

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Need a WP Disconnect for a small A/C unit that is 240V/20A. Obviously it's on an outside wall and the wall is going to be finished.

Running NMB from panel to wall, and then what I'm struggling with is how I make the penetration to the outside and terminate in the disconnect. I know you can't run Romex NMB to the outside - so what would you do - put it in a PVC nipple. If it was exposed inside, I would run EMT with an LB to get through wall in to the disconnect - but everything needs to be concealed behind the sheetrock.

Keep in mind my experience is heavy commercial in my past life, so I probably ask a lot of stupid questions as I work to learn more about the differences in residential, and light commercial.

Thanks

Brett
 
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Having installed countless amounts of A/C disconnects without any type of conduit nipple,I can`t see a problem.I use a simple plastic snap fastener type NM connector on the back KO.Since 99.9 % of our homes are stucco finished I install the disconnect on rough in, that way the disconnect doesn`t sit cock eyed on the finished surface.
 
Brett, your right about the NM not being listed for outdoor use.

That said, it is very common for NM cables to be brought through the wall into the back side of a rain tight disconnect.

In some areas of the country the entire service panel is located on the outside of the home and NM cables are brought out to that through the back.
 
Bob-- tell me how you can bring 40 circuits to a WP Main Breaker panel without violating the code other than putting a pull box inside and bring all the nm into it. My area is one of those areas where main panels were regularly installed outdoors with all the nm cables penetrating from either the wall or crawl space with a short PVC nipple (coupling and chase fitting). This seems to violate the NEC but is always accepted even in our toughest inspection counties. There is not enough connector knockouts,etc to deal with this, thus they let us do it. But this is probably another thread indeed.
 
Dennis Alwon said:
Bob-- tell me how you can bring 40 circuits to a WP Main Breaker panel without violating the code other than putting a pull box inside and bring all the nm into it.
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As far as what?

The NM being rated for outside?
 
iwire said:
As far as what?

The NM being rated for outside?
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No. In terms of article 312.5 C where no wire is attached to the box. The code gives exception to a conduit out of the top but not the back and certainly not 2" long nipples.
 
I would say using PVC nipples is a violation.

What I would expect to see is the NMs brought into the back of the panel with either single or twin NM connectors.
 
Dennis Alwon said:
That would be impossible when you have 40 circuits with range, dryer, water heaters, a/c or heat pumps, etc
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Why?

Say 15 1/2" KOs for 30 two wire circuits and a few 3/4" for others.

In a 200 amp 40 circuit panel I bet I could lay those out.

Besides, I have seen pictures of outdoor residential panels done this way.
 
iwire said:
Why?

Say 15 1/2" KOs for 30 two wire circuits and a few 3/4" for others.
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That statement reminds me of the old joke "How do you get 10 elephants in a Volkswagon? 5 in the front and 5 in the back.

Every outdoor residential panel I have ever used (GE, ITE (Siemens), & Cutler Hammer) have one or two 2" knockouts in the back on the bottom. There is simply not enough space to do it. I can't even get a 40 circuit indoor panel wired without having to use most of the knockouts on the bottom. I would bet you can't do it. Hence, this is why they allow that installation here.
 
Dennis Alwon said:
Every outdoor residential panel I have ever used (GE, ITE (Siemens), & Cutler Hammer) have one or two 2" knockouts in the back on the bottom. There is simply not enough space to do it.
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You do have a uni-bit or hole saw?
 
WP service panls outside

WP service panls outside

Just had to comment. In CA, we use 2" romex connectors or other szs if need smaller, all circuits come in the back of the panel..yes it can be done.. thanks.
 
la2151 said:
Just had to comment. In CA, we use 2" romex connectors or other szs if need smaller, all circuits come in the back of the panel..yes it can be done.. thanks.
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That is likely an NEC violation.

Unless that 2" NM connector is listed for use with the number and size of cables you use it with.
 
iwire said:
That is likely an NEC violation.

Unless that 2" NM connector is listed for use with the number and size of cables you use it with.
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Every time I see multiple cables through a large connector, it makes me a little angry. I take great effort to put the right cables through the right connectors, then some guys shortcut and put all of them in one big one. I did some research a while back to find out if any connectors were actually rated to do this. The best I came up with was Arlington's 1-1/4" connectors are rated for up to 9, 14-2's.

http://www.aifittings.com/c_20.htm

I found no 2" connectors rated for multiple cables.
 
I like to use a caflex connector, with your hole from the house just large enough to accomidate the plastic screw in. It creates a non-metalic raceway through the exterior wall penetration and the factory gasket on the connector fits tight against the wall if the hole is drilled right. Doesn't work in all situations, but it does in most. The only issue is there is no actual clamp to the disconnect.:roll:
 
iwire said:
You do have a uni-bit or hole saw?
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I do have both bit and saw but lets think about your installation. How big a hole would you have to hack out of the siding or the band of the house in order to accomplish what you think can be done? The integrity of the siding would be aborted. How would you stop water from entering through that hugh slot you would have to make for all those connectors if you caould make them fit.

Now, take a whole saw 2.5" and drill three holes. In the panel put three 2" knockouts with your ko punch or whatever and install a 2" PVC TA or coup with a slip fitting. Nice snug fit, yep, but against the code. I still say there is no legal way to do it and I believe the 3 hole method does the least damage to the house. I guess the most important thing is safety and I feel that it is safe especially if you seal the holes with fiberglass or silicone.
 
Dennis Alwon said:
I do have both bit and saw but lets think about your installation. How big a hole would you have to hack out of the siding or the band of the house in order to accomplish what you think can be done? The integrity of the siding would be aborted. How would you stop water from entering through that hugh slot you would have to make for all those connectors if you caould make them fit. .
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I would prably cut a couple of slots vertically behind the panels gutter space.

I would seal the panel to the wall on the top and sides with silicone which os what I usally do.

I believe it was Peter D that had picture of a building under construction that the NMs entered the back of the panel.

It's a big country, different areas have different ideas of the right way to do things.

Here we keep our panels in the basement so this issue does not come up around here.
 
The one thing I have a question about is, When is outside actually outside. Examples... If I cut a old work box into the outside of a house vs using a bell box, the old work box is legal correct??

8091RIns3.jpg


How can this be leagal vs using a bellbox??? or a disco?
 
stickboy1375 said:
The one thing I have a question about is, When is outside actually outside. Examples... If I cut a old work box into the outside of a house vs using a bell box, the old work box is legal correct??

How can this be leagal vs using a bellbox??? or a disco?
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I don't think either is illegal.
 
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