I know this is old, but I wanted to revisit this topic again as there are a lot of miss informations about each wall connector supposed to have its own circuit breaker.
Here in the Wall Connector guide it says the following:
Power sharing is ideal for households that need to
charge more than one Tesla at the same time, but may not have enough power for multiple electrical circuits. This functionality allows up to four Wall Connectors to share power from one circuit while still allowing your vehicles to receive a sufficient charge.
The Tesla Wall Connector is the most efficient way to charge a Tesla at home — just plug in your vehicle overnight and wake up to a charged vehicle.
www.tesla.com
I have had Power Sharing working with two gen 3 Wall Connectors connected to one 60amp breaker.
Each Wall Connector is setup to its maximum allowable amp (60 amps for 48amps continuous)
When both cars are connected which ever car has the lowest charge requests more energy. Both Wall Connectors never exceed the maximum supply amp (in my case 48 amps between the two).
As soon as one car is fully charge, the other car gets all 48amps assigned.