Under 600 V anyone can work on it. Above 600 V generally everything is restricted to qualified personnel only. See the exception to having a disconnect within line of sight. Realistically you can do it but a lot of MV disconnects are non-load break. The Joslyn Clark one is very nice as is the Federal Pacific Autojets. A lot of the others leave a lot to be desired or are private labels. For instance the Siemens one is a private labeled JC or a knockoff.