I would not risk it in your place - the Contax flashes I own have trigger voltages no higher than their DC battery voltage (5-6V).
Indeed I'd declare the 283 unsafe on every TTL flash capable camera with multi-contact hotshoe - its voltage is outrageously high. Even if the trigger circuit itself can stand the voltage, many trivial accidents (from moisture to a mishap while inserting/pulling the flash) can feed trigger voltage into the TTL circuit, which almost certainly will be toast after contact with 120+V.