I have a hard-wired 240v appliance in the garage. A junction box contains the connection between the 8/2 feed from the panel and the 8/2 appliance leads. I am removing the appliance. Is it legal to simply cap off the supply wires and screw the junction box closed? My preference would be to install a 6-50R, but the breaker is only 40a, so that's not an option. Does the breaker in the panel need to be removed/disabled so that the wire isn't live?