New circuit breaker panel 100 or 200 amp?

[JUNEBUG 88]

Our current panel is a 100 amp panel and I need to either get a sub-panel or get a panel with more spaces to take care of the problem of too many double pole circuit breakers prior to upcoming inspection.
Situation: I would like to in the near future, 1-2 years, upgrade to 200 amp service, but can not afford that now as part of the service run is underground or through the garage. To connect to water meter is a run of 40' for the ground.$$$$
We have a 100 amp main breaker in attached garage between the meter and the house main breaker panel. To save money in the future,and not throw out the new panel I need now, can I put in a 200 amp 40 space panel in the house?

Remember the circuit breaker in the garage is 100 amp for the 100 amp service I have so that would be protecting the house panel, Correct?

I just do not want to buy a 100 amp box now and then throw it out in two years when I do not have to.

[HayZee518]

about the only way you can do this is to use a 200 amp 40 circuit sub panel with main lugs and backfeed a 100 amp breaker to energize the bus. MIND YOU, you CANNOT just upgrade to 200 amps WITHOUT changing the leads to 4/0! and the main breaker to a 200 amp [backfed] breaker. 100 amp is 2/3 aluminum seu. 200 amp is 4/0-3 seu.
Ground wire is #4 stranded copper for the 200 and #6 stranded copper for the 100 amp service ground.
ALSO - the size of your conduit that houses the feeders needs to be increased for 3 or 4 4/0 aluminum individual cables. two inch trade size pvc or metal conduit for 4/0 X 4 or 3 cables, 1 1/4 inch for #2 3 or 4 cables