Dec 14 2017 13:30
"Would it be fair to say that a USB charger module added to a socket outlet is a fixed wired appliance and therefore not part of the installation wiring?"
No, it's not an appliance (as defined in the Act). From an ESRs perspective, t's a fitting connected to installation wiring. From a Wiring rules perspective, it's in the nature of an electricity converter ( LV > ELV, ac > dc), but could also arguably be classed as a kind of ELV socket outlet.
"Replacing a GPO on a non-RCD circuit with a GPO that includes a USB charger doesn't trigger the requirement to add RCD protection."
As far as 184.108.40.206 goes, yes Exception 1 applies: replacing an existing socket outlet with another socket outlet; specifically permitting replacement of single with multiple - and by implication also for double to quad, double to single, or any type to one including an ELV socket.
But add the USB on a separate plate, no longer a replacement; but instead an alteration to the subcircuit (adding a point). Unfortunately 2.6 doesn't differentiate between LV & ELV sockets when it comes to RCD protection, so RCD required.
Nor does 1.4.86 definition of socket outlet.
Not the only problem with 2.6. 220.127.116.11 doesn't allow a socket added to an NZ non-domestic (non-school) to avoid RCD - 18.104.22.168 doesn't require RCD for new subcircuits outside of schools, so there's no exception to pick up via 22.214.171.124.
Next edition is better, but in my view still not fully correct.