Lets say you have a keyswitch for a roll up door and you want to take out the cylinder and you are told the power is off because nothing happens when you turn the key. Do you believe them? How do you tell? I told the guy pull off the wires and hand it to me and he didnt want to. These have to be around 240. Also if you have a switch for a spa with a shutoff button is there a way to tell if all power to it is off?

