Checking if there is a way of accessing an independent earth in the workshop. If there is, then whatever it is (pipes etc) need to be included in the main equipotential bonding. Hence that will also need to be carried on the SWA CPC.
There is a (rare) failure mode with PME supplies, that a loss of suppliers Neutral (the so called Protective and Neutral conductor that comes into the building), then your installations neutral and hence earth will be left floating, and connected to live via all your appliances.
This could result in live casework on the kiln. This becomes dangerous if you can touch something else that is still connected to a real earth. If all the stuff around you is only earthed via the PME earth, then it should all be sat at the same elevated voltage, and hence not pose a direct shock risk.
Yup, especially with slow start - that could push it well into the cycle.
Click to see the full signature.