Job I'm on at the moment has a fair bit of the lighting wired in steel conduit, which also provides the CPC for the circuit. I'm getting high results on continuity tests (typically above 10ohms, sometimes a few hundred) and soft non tripping loop tests (typically 50-100 ohms), but a high current loop test returns values which look much more sensible.
My thinking at present is that the joints in the conduit are starting to corrode or form a layer of oxide and this affects the low current tests, but the full loop test manages to arc past it, and that while in the current situation if a fault were to occur it would probably have the same effect and would cause the circuit to be diconnected correctly (though we cant say that with certainty), is that its an unacceptable situation because it indicates the conduit is starting to break down and it could eventually progess to a stage where the continuity is totally gone, and therefore is not an acceptable situiation to be in
Just basically want to ask if people generally agree with my assement of the situation, or if others would just bang a high current loop test on and be happy if it gave an acceptable value? ,just don't want to make recommendations and theh have someone else come along, contradict me and say 'its fine, zs checks out ok'
My thinking at present is that the joints in the conduit are starting to corrode or form a layer of oxide and this affects the low current tests, but the full loop test manages to arc past it, and that while in the current situation if a fault were to occur it would probably have the same effect and would cause the circuit to be diconnected correctly (though we cant say that with certainty), is that its an unacceptable situation because it indicates the conduit is starting to break down and it could eventually progess to a stage where the continuity is totally gone, and therefore is not an acceptable situiation to be in
Just basically want to ask if people generally agree with my assement of the situation, or if others would just bang a high current loop test on and be happy if it gave an acceptable value? ,just don't want to make recommendations and theh have someone else come along, contradict me and say 'its fine, zs checks out ok'