Hmm, we're all worried about splicing, that should not be a big deal when burying cable. Your deal is what to do with electrical boxes & outlets that are ABOVE ground/sea level. You need a BELL housing. What I'm refering to is an encasement with an open bottom, big enough for whatever box or cabinet you need to protect, and enough room to reach up and plug in connections to outlets, check breakers, etc.. The top can be fastened down with a couple of bolts, just make sure that the top is leakproof, otherwise air will escape as the 'bell' is being submerged and still flood the compartment. This can be a heavy plastic bin or metal container, nothing fancy. I'd just watch putting my hand up into it each time, wasps or something may build a nest up in it.
