A person wants to add a meter to an existing 200 amp service to split up the apartments in a house.100 amps is to be the second service. What would be the best way to go about this? A double 200 amp meter socket or spliter box? The second panel will have a 100 main breaker does this serve as the service disconnect and does the second panel have to be grounded with 2 ground rods? What would be the best way to go. Thanks

Are you doing this or is an electrician?
Are you the homeowner?

From the tone and content of your question I going to guess that you are a novice at doing electrical work.

With that in mind, there are several things you need to be made aware of. First please add me to your beneficiaries list in your will. Might as well add Stan also. :)

Much of the work on the meter would have you working on unprotected circuits that are basically kill zones if you do not know what you are doing!

You need to start this discussion with a call to the power company to see what they are willing to do for you. Meters are the property of the power companies and they tell you where to install them.

Next on the list would be the "Permits and Inspections" department to verify they will allow a homeowner to do this work.

If you are truly a novice, please consider getting the service of a licensed electrician and have him/her pull the permit for the work to be done.

The National Electrical Code is about "Safety". And the area you would need to work on is both very dangerous and complicated.