3 phase 3 wire system???

[electicamateur]

I have an irrigation system that is 3 phase 3 wire 240volt. I would like to have an outlet or two that I can plug in tools and/or an RV maybe. I tested the phase to phase leads and all 240V +.  Phase A & C to ground is 120V+ while phase B to ground is 208V +.  The problem I see with the 3 wire system is that there is no neutral (4th wire) to use for a single phase outlet/panel.  Any ideas or help would be appreciated. Thanks.