Here is the picture of a T/R switch I built. There was no evidence of arcing or problems with 1000 watts input with key down. On 160m the unit switched between dipole and verticle.
The switch uses manual switches and in the auto mode transceiver output for switching. The relay provide the logic to support the switch modes.
Control Panel for the 1000W T/R switch. Right: Man Vert and Man LNA only works when the (center) switch is in the MAN position. The left switch is either in bypass (thru mode) or controlled switching automatically from the transceiver