I figured there might be different terminologies in other countries, should have put more effort into my first post. In Australia it's a Residual Current Device (see pic.) This is located in the main power box in my shed.
I have been over the wiring a number times since the problem arose. Main thing is it worked fine previously and is an issue that came about overnight. This leads me to think it may be a product (filter) failure. Of the 3 filters currently installed in the system it's only 1 that trips the RCD. Are there better filter units available without breaking my bank maybe?
I was informed by a friend that I can rewire the power point that runs the mill to bypass the RCD. For me, this would be a last resort as I figure the RCD is there for a reason. Most likely to stop me burning my shed down or electrocuting myself.