How to Connect Conduit to Back of Main Panel

[exranger06]

I'm trying to install a subpanel in my garage. The easiest way to get the wire from the main panel to the subpanel is to use a knockout on the back of the main panel and go straight through the wall to the outside of the house, and run a conduit on the exterior of the house. The conduit will be less than 10 feet in an "ugly" corner of the house where there is already lots of utility equipment and an AC condenser, so I'm not concerned with looks. I'm planning on using 1.5" rigid steel conduit. My question is, how do I connect it to the back of the main panel? I was going to buy one of these connectors:
http://www.homedepot.com/p/Halex-1-1-2-in-Rigid-Water-Tight-Conduit-Hub-16315/100118103
But I'm not sure how I can use it with that large flange on the connector. I would have to drill a large hole in the siding and maybe caulk around it when I'm done. Should I just use a threaded nipple to go through the wall and just use a locknut on the end inside the panel? The conduit will go into an LB as soon as it gets outside.

 

[Donald]

The back of a panel seems to be pretty busy with the buss. I would go through the top. Remember you need 4 wires, isolated neutral and ground.

 

[exranger06]

There is a large knockout available on the back side of the panel that's perfect for running the conduit out. The bus doesn't go all the way to the bottom of the panel. There's a good 3-4 inches of space between the bottom of the panel and the bottom of the bus on the back side. The main panel is in my finished basement with drywall all around it. Going out any other side will require hacking up drywall which I'm trying to avoid. Also, the top is actually the most crowded place, as almost all of the branch circuits exit the panel at the top.

 

[BigCahuna]

Making this type of connection in the backside of the panel at this point in time can be a pia. You'd be better off coming into the side of the box, and use a locknut on the outside and inside of the box. Along with a blue bushing.,,

 

[exranger06]

An electrician apparently ran some conduit to the back side at some point in time. There are two conduits connected to the back that were obviously after-the-fact. I'll have to take a look at how he did it when I get home. I agree that this is really turning into a PITA. I just had a thought though. I can maybe cut a small section of drywall out right next to the panel and use a knockout on the side. I can use an LB to make a tight 90 degree turn and go right out the wall. I know the LB has to be accessible and I can't drywall back over it. I can maybe get some kind of access panel and install that over the hole.

 

[KJSmith]

Use a nipple and 2 "locknuts". One to keep it from going in to far and one on the inside.

Seal around the nipple where it comes out.
I would also seal around the wires inside the conduit in the panel.

Why 1.5".

 

[exranger06]

Originally Posted By: KJSmith
Use a nipple and 2 "locknuts". One to keep it from going in to far and one on the inside.

Seal around the nipple where it comes out.
I would also seal around the wires inside the conduit in the panel.

Why 1.5".

That's basically my plan. I was just concerned about drilling a large hole in the exterior of the house to get the locknut through and having a gap all the way around the conduit. I'm using 1.5" conduit because I'm using 2-2-2-4 Al SER cable to feed the panel, and a customer service rep from Southwire recommended that size conduit for that cable.