While we code to the current regulations we seem to make allowances usually a C3 for earlier installations.
for example Arc Fault Detection Device in a high risk residential building, if the building is 20 years old this makes sense, otherwise we would have to upgrade many properties.
how should we code if the building was wired recently when Arc Fault Detection Device is required .
Arc Fault Detection Devices were just picked as an example but could apply to any changed requirements where the installer has not met the regs at the time.
