"that has 19 mm NPT fittings?"
Allow me to explain our wonderful measurement system
NPT (National Pipe Thread [US]) is measured by the inside diameter of a steel / iron pipe. So the measurement is sort of nominal as the inner diameter will be different for all different materials and such, while the outside diameter is constant. I think you're talking about a cable gland fitting that would screw into the electrical box. The most common size for that would be 1/2" NPT, basically, though it's meant for rigid conduit (same thread standard) or for adapters and cable gland type things. You could probably search for 1/2" cable gland. The next size up, however, would be 3/4" which is almost exactly 19mm. So your measurement is a little confusing. I'm reasonably confident what you need is 1/2" though, as the *outside* diameter of 1/2" NPT is roughly 19mm so if that's what you get when you measure the hole diameter, that's 1/2".
It's important to note that outside of the Americas, the rest of the world uses BPS (British Pipe Standard). It's also imperial, and as a matter of fact, almost identical to NPT with one critical difference: the Brits used a different thread angle. In plumbing, this makes NPT and BPS completely incompatible, as the threads are responsible for sealing. For your purpose, a 1/2" BPS pipe fitting should thread in with no issue. I'd imagine you might be able to find some sort of pipe fittings to concoct an adapter to use parts available to you. Other than that, you could get some shipping quotes from American companies, like McMaster or Grainger. It's probably expensive
Is this machine even made in the Americas? If not, it's probably BPS.
The ebay search below brings up some things that are not too terribly expensive, but it seems like it's either coming from the US or China.
https://www.ebay.com.au/sch/i.html?...able+glan.TRS0&_nkw=1/2"+cable+gland&_sacat=0