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I'm trying to build a laminar flow hood for mushroom farming, but the centrifugal fan wiring has me a tad confused.

I've attached two images so you can see what I'm talking about. So I was expecting live, neutral and earth wires but that's not exactly what I've got. As you can see on the wiring diagram it references 4 wires, though there are only 3 - the earth wire is missing.

Do I just assume its doubly insulated? Just connect the capacitor between blue and brown, active to brown and neutral to black?

Thanks!

Before the electricians respond, is the 4 connector terminal block supplied with the fan?
And what is the material of the fan on the outside?
Excuse me for observing, the end wires do not look factory new!

The wiring diagram indicates that an earth is required, is it missing due to the stricter saws in Australia (only licenced electricians being able to install / replace or repair things such as fans, lighting switches / pendants, plug sockets and even a plug for an appliance?)

Could it have be left out in expectation that the licenced electrician will make up the earthing circuit for the fan motor? And dissuade the public diy'er from attempting to install tit themselves?

It seems the start capacitor is wired away from motor, not seen this with fans, but have seen it with submersible pumps, there is a control box between fan and supply you have not shown, not sure why, but it will need that box.