Lewys and I looked at the laser cutter this morning to determine what was going wrong.
When we used the test button on the power suppy for the laser tube and it was unable to fire the laser but didn't trip the RCD.
Afterwards we tried using the pulse button after this we could see sparking inside the power supply and the RCD was no longer tripping.
We pulled the power supper out and it looks like it may have have had water leak in to it at some point in time.
I've ordered a replacement power supply for the laser tube but think we should probably look at replacing the water lines before installing it.
The new power supply should arrive in the next 2 weeks.
Mitch