[billybob1]

i have an existing 100 amp main breaker box i want to upgrade to 200 amp but that means moving the box approx 5' from the existing. can i use the existing 100 amp box(i will clean all breakersa out) as a junction box to make connections to lengthen the wires?

 

[vsheetz]

What is it that forces the relocation of the panel when upgrading?

 

[J. V.]

i have an existing 100 amp main breaker box i want to upgrade to 200 amp but that means moving the box approx 5' from the existing. can i use the existing 100 amp box(i will clean all breakersa out) as a junction box to make connections to lengthen the wires?

No. You need a new panel. You need a new service. The structures (house) service is rated for 100 amp and must go if you plan to upgrade to 200 amp.

You can buy the new panel and install it while the old one still serves the residence. (build a new service). If you can move the meter, you can go ahead and install the new meter and the wiring. Then when you are ready you can move the wires to the new panel. If you can keep the old panel, remove all the guts and use it for a big junction box. Just run a couple 2" conduits between them. You can connect the old small wires together in the old panel and use it for a pull box for the new panel.
Just my thoughts. I am certain we will hear many more. Stay tuned.