The other day I saw a mobile home wired with a 4/0 4/0 2/0-4 al feeder assembly. I looked it up on the net and sure enough they sell this cable assembly in this and in 4/0 4/0 4/0 2/0. They were both rated at 200A. I thought you needed a full size neutral and grounding conductor for a mobile home? What gives? Is there ever a reason that your allowed to downsize a neutral and grounding conductor? If there isn't why do they make this cable combination? Please explain with code references . Thanks

I looked in 550.33 in the '02 NEC and it reads like as long as you can meet the requirements in that section you are good to go. I wonder if your "feeder assembly" meets all these requirements and is Listed for use with a mobile home?

Is the 3d wire insulated?

Hey thats all the supply houses here carry.The 4/0 quad(use) It has 4/0 4/0 2/0 4awg The cables at the big box stores have 3 or 4 4/0 and you need to buy a lug for the panels for the ground wire and neutral.