6 gauge wire for 60 Amps. If you are running 240 volts i would do 6/3 romex.
Yes, this breaker can be used in a General Switch panelboard. Inside the door of your panel there will be a label and on that label will be the list of circuit breakers approved for use in the panel. On that list you will find Bryant BR breakers. The Eaton/Cutler-Hammer BR breaker replaces the Bryant breaker.
It can if the panel is designed to use a branch circuit breaker. It would require it to be secured to the panel by a screw through the hole visible in the lower middle of the breaker especially if the breaker is installed with the feeders backfeeding the breaker. Note: only as approved by the panel manufacturer.
It will in a siemens wp4611
Please hire an electrician. These breakers do not accept a white wire, they go on the neutral bar in the panel.
This will take two spaces in the panel, each pole is the same size as a normal breaker
No, this breaker will not fit in a Zinsco or Zinsco style Sylvania panel. For a replacement breaker do a search for Connecticut Electric breakers, they make a Zinsco replacement although they are very expensive. The best option, however, would be to replace the panel. Zinsco panels are known fire hazards.
I used this breaker with #8 gauge with no issue.
Eaton/Cutler-Hammer has two panels, the CH series and the BR series. This breaker will only fit the BR series of panels.