Have I got a faulty 1.5kw spindle

[Muzzer]

Bummer. They should be doing insulation tests before they ship the products. It's always a risk when you buy Chinesium stuff - the downside of the cheaper deals.

I guess this highlights the importance of correct installation protective earth connections ("equipotential bonding") to all exposed parts. As a general rule, protective earth wiring should be at least as thick as the supply wiring and the fuse rating should be low enough to prevent any of the wiring burning out before the fuse in a fault condition.

You have an RCD here which trips out before any fuses etc are blown or people are fried. Ideally you should have had your protective earthing connected up before this happened but hopefully now you can see how it's important. The danger of relying on a fuse rather than an RCD is that you might pop your VFD and the protection would rely on blowing the fuse which is more of a test of the wiring.

Bottom line is to ensure exposed metallic stuff (including the machine body itself) has a good hard earth connection, particularly if it's been sourced from China! I'm always careful to install and test the main earth connection and ensure everything has a good connection to the (grounded) cabinet / chassis. I'm sure there must be some real horrors in home workshops around the world.