DIY 3.6 kVA Variac control station.

I've had this Carrol & Meynell CMV15E-1 Variac for quite some time.
It is a really useful tool for soft starting old or big incandescent lamps and running equipment designed for a lower voltage.
You can also null out any fluctuations in the mains supply when taking measurements. (My mains varies from 248 to 253v)

I later built up a test box which plugged into the output of the Variac which allowed me to monitor what was going on without messing around with clamp and multimeters.
This worked but it was still a bit of a pain with cables and leads going everywhere so I decided to build an enclosure that holds everything together in one unit.
This is the result:
The switch on the left energises the power meter and also closes a contactor which feeds the input of the variac.
The switch on the right controls another contactor which supplies the 3 outputs below.
For flexibility I have added 3 different output sockets: A standard UK BS1363, a C19 and also a C13.
All outputs are protected by an 16 amp MCB and the control side is protected by a 1 amp MCB.

In order to limit the inrush current (this thing likes to take out 32 amp MCB's!) when the main power input contactor is closed, the power goes through a resistor (a 250v 15w Atlas Pygmy lamp) to limit the inrush current which is then shorted out after a 3 second delay by another contactor. The main output contactor can only be closed after the shorting contactor is has pulled in.

Despite being rated for 15amps I have tested this unit with loads of over 20 amps for short periods and it does seem quite happy being overloaded at least for very short periods!

A quick video tour can be found Here