Some key remarks on 'ampacity' at 1min20sec.
I wonder if the tripping has only just begun to happen which would indicate some sort of failure leading to increased earth leakage or current drawn. What follows assumes it has only begun to trip.
I suspect it is intermittent tripping and happens depending on when the X ray valve is pulsed on in the cycle of the mains voltage waveform. The switching on and off of the X ray valve will take place on the mains side of the transformers. Typically the X ray valve current ay 70kV is 7mA - I will use 10mA for my estimates. These are peak values.
70 000 x 0.01 = 700Wpk. Not a lot for a 16A mcb/RCBO but the current will not be sinusoidal but more like attachments 1 and 2 depending on the nature of the LV to HV power supply being inductive or capacitive.
The RCBO's fast magnetic overcurrent trip may be tripping because of a very high peak current if the X ray is pulsed on when the sine wave is crossing the time axis for an inductive transformer or at peak voltage for a capacitive switched mode PSU.
Why would this affect the 32A RCBO. The high but brief current of the X ray machine may:
a. create a voltage drop along the neutral feeder to the DB sufficient for the RCBO's functional earth electronics to 'think' the neutral has become open circuit;
b. the 32A RCBO's electronics is sensitive to the voltage disturbance;
c. the EMC/EMI filters in the IT server respond to the short but fast voltage disturbance when the X ray pulses on and off by creating earth leakage current L-E and N-E the sum of which is not zero and greater than the prevailing trip threshold bearing in mind the IT server is on a final circuit with other kitchen equipment.
What to do? Some suggestions on what I would try:
1. Establish if the 16A RCBO is the correct rating and type for the X Ray machine;
2. If the wiring allows, swap 16A RCBO for a 20 or 30A RCBO and see if further trips happen again considering type of RCBO;
3.
Temporarily and only during you attendance on site connect the DB's N and E busbars together using at least 6mm2 - this ties the N and E voltages together irrespective of the surge current through the feeder N conductor;
4. Move the X ray supply to another phase - may still need to uprate the RCBO though.
5. Upsize the feeder to the DB.