i was under the impresion that befor u can alter a circuit, the main and suplimentary bonding must be up to scrach, does not matter were the alteration takes place. am i wrong?
Under 16th edition if you were doing electrical work in a bathroom then you would need to make sure that both supplementary bonding and main earthing were up to standard alongside all of your other prescribed tests.
Under 17th for bathrooms you still check the same but can omit the supplimentary bonding so long as:
1. All ccts in bathroom meet disconnection times (Zs)
2. All ccts in bathroom additionally protected by 30 ma rcd
3. All extraneuous conductive parts are effectively connected via main bonding to the MET
However all of the above applies to bathroom installations, so unless you have a bathroom where you can install a socket outlet at least 3 metres away from zone 1(edge of bath or shower tray)
then you wont be allowed to install a socket outlet in your bathroom
So this now takes us to where we were previously. If you are just adding a socket outlet to a cct (not in a bathroom) and are not installing a new circuit then this will be a minor works certficate not related to the bathroom.
So with this in mind this is what you need to verify
1 That the earth contact of socket outlet is connected to MET (r1 + r2 test)
2 Measure the insulation resistance for the whole of that circuit and compare results to table 61 ( min 1meg ohms)
3 Check Zs
4 Check and confirm polarity
5 check effective operation of the rcd protecting that circuit. If one wasnt fitted before you will probably have to make provision for this now.
So for this scenario you will not need to check if supplimentary bonding is adequate in the bathroom.
However it would be good if you could give more detail as to the socket outlet addition that you intend to do.
Hope this helps