The KM3NeT Collaboration has started the implementation of the first phase of the ARCA cubic-kilometre-scale neutrino telescope in the Northern hemisphere integrated in a platform for Earth and deep sea sciences. The ARCA detector will be located in the Mediterranean Sea close to the Sicilian coast, about 100 km offshore Capo Passero at a depth of 3500 m. This location will allow surveying a large part of the sky, including most of the Galactic Plane and the Galactic Centre. Theoretical models for neutrino emission, that predict neutrino fluxes from gamma-ray and cosmic-ray measurements, can be robustly constrained by the neutrino observation with a detector with an excellent pointing accuracy such as ARCA. In the KM3NeT Letter of Intent the first estimates of the discovery fluxes from benchmark fluxes from candidate Galactic neutrino sources have been reported together with the discovery flux for generic $E^{-2}$ point-like sources. A more sophisticated analysis has been developed by the KM3NeT Collaboration and new expectations will be shown not only for the supernova remnant RX J1713.7-3946 and the pulsar wind nebula Vela X but also for other potential neutrino sources in our Galaxy. Expectations for a generic point-like source with a spectrum proportional to $E^{-2}$ will be reported.