As a Computer Network Tech, this is my bread and butter.
The shielding is probably a little overkill, but why not, there is a possibility [garantee] of the Generator building up EMF noise later on.
The connector on the network card for the PLC should have a Shield ground point, Manufacturers have been requred to use one since about 1999, mostly because they can't buy the unshielded surface mount RJ-45 connectors anymore.
On the card I don't see the ground tab on the circit board, but some of them are a surface mount which I can't see.
The NetOpia router definatly has the ground tab on it. (I have not found anything new without the shilding tab in years)
That said. Here is a link to RJ-45 Crimp Terminators, http://store.pchcables.com/rjshmoplfors.html
With Ethernet the sheilding being grounded is optional (Defeates the purpose mostly) but otherwise it does shield high level EMF and Radio static.
Also they are not technically grounded. There is a large resistor in place to prevnt a true ground out and Fire hazzard.