How to tell if your property has three-phase or single-phase power lines. Look for three parallel lines mounted at the top of a wood pole in a T-formation.
How to Identify a Single-Phase or 3-Phase Power Supply
Cornell Cooperative Extension
How to tell if your switchboard is single phase or three phase?
How to Identify a Single-Phase or 3-Phase Power Supply
Solar Farm Land Requirements & Solar Developments, YSG Solar
What is 3-phase electric
Three-phase electric power - Wikipedia
Solar Farm RequestGreen State Power
Is this power line 3-phase and can it support power transmission from solar? : r/solar