is this a laserwash by any chance?
i'm doing one right now, but from the ground up. its a 3 bay auto with 3 wand bays as well.
the loads should be taken into consideration when sizing the service.
the existing panel should be converted to a subpanel as per code specs and could be fed from a lug kit ordered with the panelboard to save the cost of a 200 amp breaker.
the units being installed on my job require a 200 amp, 3-phase/208 volt breaker each, plus the additional lighting and motor loads.
and yes you can install them side by side.
