Fuses

Is it legal to connect the air compressor to a 30 amp fuse, or can we only use semi automatic fuses?

Per R55, your choices are 20 Amp fuse or 20 Amp snap-action circuit breaker.

If the compressor is used, the air compressor Spike relay power feed must be protected with a 20A fuse or 20A circuit breaker. No other electrical load can be connected to this breaker.

I recommend the circuit breaker, which won’t usually trip from the current spike during compressor startup. The fuse can really ruin your match if it burns out.

To be more accurate…
<R55> …
 If the compressor is used, the air compressor Spike
relay power feed must be protected with a 20A fuse or
20A circuit breaker. No other electrical load can be
connected to this breaker…
 Relay modules must be protected with a 20A circuit breaker.

The first section allows you to replace the Spike 20 amp fuse with a circuit breaker. If you don’t do this now you will later after you have gone through a box of 20 amp fuses. The second section stipulates only 20 amp circuit breakers must protect a relay module.

Start current on the compressor can be 25 amps while run current is 10-12 amps.