On Tue, 3 Mar 2020 20:14:01 +0000, Skyhawk
m wrote:

Have had the same set up for the past three years with no changes or issues.
240 v unit, 30 amp breaker. Twice in three days the heater has sparked and
tripped the breaker. Open the cover and everything is hooked up but one
connection, supply side of the thermostat, has evidence of arching. Cut the
burned wire nut off, stripped the wires and reconnected. Two days later it
happens again. Still a loose connection or other possibilities?
Still arcing? or just tripping the breaker? I'd change the breaker
if you do not have evidence or arcing and replace the heater (or the
thermostat) if there is.