How to implement PEC boundary condition in PDE Toolbox's harmonic electromagnetic analysis?

I am working on a simple frequency-domain electromagnetic analysis of a coaxial transmission line in PDE Toolbox. I could describe conductors as media with high conductivity but this requires dense meshing. Hence I would like to describe them as perfect electric conductors (PECs). Is there a way to specify such a boundary condition in the harmonic analysis? I inspected 'electromagneticBC' but this function forces me to provide all vector components while PEC says only that the tangential component is zero. Any ideas?