Another sub panel in a detached pole barn post

[MZ 500]

I am planning to run 2-2-2-4 Mobile home feeder to my pole barn and want to clear up a few questions.

First off I plan to run it in conduit even though it is rated for direct burial; I want to run coaxial cable out to the bar as well.
Right now there is 110v 3 wire going out to the pole barn there is a 2” conduit that goes out just below my main panel (about 6” maybe) and down the outside into the ground from there it is direct buried to the barn.

#1 can I run the 2-2-2-4 out the bottom of the main panel and into this existing conduit or does it need to be in conduit all the way into the main panel?

#2 in the main panel when I connect to the neutral/ground wires I assume I need to get some larger lugs that bolt on the existing neutral terminals like this. I plan to use a 90amp braker.
http://www.homedepot.com/buy/electr...-electric-breaker-box-neutral-lug-136411.html

#3 Grounding at the barn I have read that I need to separate the ground and not hook it to the neutral Leg in the sub panel and run the ground to two ground rods, why two rods?
I am using a 100amp sub panel in the barn my main panel is 150amp.

 

[Jefe]

The experts will be along shortly to answer your questions specifically, but from my recent experience:
The ground rods are dictated by code. Check with your local authority on whether you need one or two. I was told I only need one. Two wouldn't hurt though.

Another thing, double check that the MHF you buy is rated to be run indoors, otherwise you'll have to change wire types when you enter the house. My understanding is that if it is only rated USE-2 it is NOT suitable for indoor use. (lots of threads about that here.) Again from my inspector, (and the internets) if it is also marked RHW-2 it is ok indoors.

 

[pattenp]

The MHF should have the RHW-2 rating to be run inside the structure. Also all runs of individual wires inside needs to be in conduit, so this means the MHF will need to be in conduit when run inside.

As far as the ground rods go, code requires the grounding rod to have 25 ohms or less resistance. To test for this is expensive so it's cheaper to use the code exception of putting in two rods.

You can use the larger lugs as you have shown.

Edit: The existing 110V 3 wire circuit needs to be remover or disconnected. It's against code to have 2 feeds running to an outbuilding.

 

[MZ 500]

I am pritty sure the wire has the RHW-2 rating as well but it is individual wires so I will need to put it in conduit but since the hole is just below the main box I should be able to use one of those 90° fittings with the cover to get up to the bottom of the box. Oh and I do plan to pull out the old 3 wire. Am I ok to run the coaxial cable with the 2-2-2-4 in the conduit? Aslo do i need to run two ground wires (one to each rod) or one wire and pigtail to the other rod?

Thanks for the help guys!

 

[pattenp]

You should not run any other wire in the same conduit with the feeder. You also need to use a grounding block on the coax so it can be grounded. The ground electrode conductor to the rods should be one continuous wire. The ground rods need to be at least 6 feet apart from each other.

 

[MZ 500]

Well I did some looking last night and the wire is rated for RHW-2 so I am good there but I did find that the 2" conduit that has the existing 3 wire to the barn also has the 3 wire that goes to my septic lift pump so my plan is now to run a second 2" conduit for the 2-2-2-4 right into the back lower corner of my main panel I am pritty sure there is a knock out in that corner, sound good?