I did this a while ago. I had a variac (a variable transformer that can convert 120V AC into 0-140V AC) sitting around and figured I should build a case for it. I wanted a rugged case, and one that was portable. So off to Princess Auto (a farm tool & stuff store with a cool surplus section) to buy an old military ammo case.

I cut holes in the case, and mounted the unit inside. Wired for 0-140V range, with a safety fuse, power switch, built in meter and power light.

For output I installed 3 banana / posts and a standard 120V single phase (North American style) outlet.

The analogue meter works.

Complete!

Enjoy!