Grounding for outdoor load center
We are in the process of moving our mobile home 200' or so to a permanent foundation, which will require a new meter/disconnect structure. We currently have a rather outdated 200A/100A disconnect system that sits on either side of the current meter feeding the home and a detached shop/barn. Once a new 320A meter socket was picked out, I decided at someone's suggestion to go with a 200A outdoor load center (Siemens W0816B1200CT) with through-feed lugs to service the mobile home. Within the load center I'll use a 100A 2-pole breaker to service the shop and a single-pole GFCI breaker to service an outdoor outlet nearby.
The 200A disconnect currently in use is grounded with a ground wire connected directly to the box and into the ground. The 4th wire (ground) going to the service panel inside the MH is also just connected to the side of the 200A disconnect box. Now, in the new Siemens load center, I could make accommodations to ground it similarly, or I can conveniently use the dual neutral/ground lugs on the neutral/ground bar inside. According to an article I found on Self Help & More, "(t)he grounding electrode conductor may be run from the grounding electrode system to the neutral/grounding combination bar or bars located in the main service rated panel or disconnect." Am I good with this neutral/grounding combination or should they be separate as with the current disconnect?