I've got a customer that is having a water problem entering through the service which enter the house below grade in the basement. From there they have 4 150 amp panels branching from a gutter. To solve the problem I need to rebuild the service, putting all the disconnects outside and re-entering above grade. All currect service cables are fairly new and are 4 conductor.

Can I splice each of these cables in a j-box or gutter? I can't find a code prohibitting splicing the main, I've just never had to do it.

Thanks