triple,
Are you talking about poly-phase pumps?
I had a situation over here that needed a solution similar to what you have there.
What I did was made up some stainless steel bollards (for want of a better term) that had a base plate that was Dyna-Bolted to the floor (with stainless rawl-bolts) and from there, welded a plate on to the bollard to take the controls/pump isolator.
Reason behind the stainless hardware is that if this area could be wet quite often, zinc-plated or even galvanised stuff is not going to last.
In my niche of the trade (the dairy industry), things get wet all the time, use something like galvanised steel at your own peril.
What's more, is that if you can plan it to have your conduit come up through where your bollard will be placed, you have instant mechanical protection for your wiring as it comes out of the ground.
