Air con blowing 20a MCB a few weeks into box change in shop/commercial

[The Ghost]

Strange day, changed DB in shop couple of weeks ago from old wylex with cooked neutrals and burnt out neutral bus. Wiring was the usual sargasso sea of cables above suspended ceiling, old circuits, redundant circuits and really bad light switch arrangement. Pulled out the switch wires (six) and re-located into grids at reachable height and so on. Fully expected to be called back for RCD problems.
Got a call regards the air con MCB popping a couple of weeks in. Thought mhmm just megger cables (SWA) and flexible control cable from outside fan to unit. Not possible as could not disconnect or access cables on outside unit. I suspect the outside fan is jamming but can't even look at it as it is inaccessible. Do not really know about air con apart from the obvious general principles. Anyone up on air con? Its a Fujitsu in suspended ceiling quite old by the looks of unit.

 

[Pete999]

Pete999, as mentioned previously, i am a/c refcom certified installer / maintainer. I mentioned the air off simply for the OP to stick his hand near it perhaps with a thermometer, not start to be a refrigeration engineer, politely you have some knowledge of a/c but its either out of date or you have not experienced the full spectrum. Modern systems manipulate pressures and have quite robust protections in place, air off is very reliable. Many systems now are VRF the indoor unit is not powered from the outdoor unit, just saying

So if it's a normal cassette type A/C split unit as they used to be called where do they pick up their supply from?

 

[Pete999]

Pete999, as mentioned previously, i am a/c refcom certified installer / maintainer. I mentioned the air off simply for the OP to stick his hand near it perhaps with a thermometer, not start to be a refrigeration engineer, politely you have some knowledge of a/c but its either out of date or you have not experienced the full spectrum. Modern systems manipulate pressures and have quite robust protections in place, air off is very reliable. Many systems now are VRF the indoor unit is not powered from the outdoor unit, just saying

So if it's a normal cassette type A/C split unit as they used to be called where do they pick up their supply from? Oh and in addition I don't, never have described myself as an A/C expert, I was just passing my limited knowledge on to someone who has less experience than me, by the way it was never mentioned that the system was a VRF type system, just saying.