Will it be okay to override a PIR using a key switch, incase the PIR stops working?
If the PIR has a relay output (the type that goes click when switching) then no problem. Some types though apparently have electronic outputs which don't appreciate being fed 230V the 'wrong way' (which can happen if your extra switch is simply in parallel with the PIR output). If you only use the override switch if the PIR has failed then it might not be too much of an issue. Alternatively use a 2-way switch to switch the light between the PIR's output and permanent L, so that the PIR doesn't get back-fed.
Will it be okay to override a PIR using a key switch, incase the PIR stops working?
If the PIR has a relay output (the type that goes click when switching) then no problem. Some types though apparently have electronic outputs which don't appreciate being fed 230V the 'wrong way' (which can happen if your extra switch is simply in parallel with the PIR output). If you only use the override switch if the PIR has failed then it might not be too much of an issue. Alternatively use a 2-way switch to switch the light between the PIR's output and permanent L, so that the PIR doesn't get back-fed.
