Insulation
The Insulation boundary condition node adds two types of boundary condition, namely an electric and a magnetic boundary condition. The electric boundary condition is expressed as
which is a natural boundary condition. It corresponds to the Electric Insulation node for the Electric Currents interface.
Electric Insulation in the COMSOL Multiphysics Reference Manual.
The magnetic boundary condition is expressed as
and sets the tangential components of the magnetic potential to zero at the boundary.