TT Testing
- Thread starter sparky999
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I`m going to stick my oar in here. I`d make certain that there is nothing else connected into that cable, or the rod. 6.69 ohms Ra is MUCH lower than I`d be comfortable with.
Where you are asked for max Ze, insert Ra on a TT system. 30-90 ohms typical. <10 suggests either:
1. an amazingly good rod
2. a parallel path, as suggested above.
Max Zs for mcb`s has no bearing on a TT system, as they are seriously unlikely to trip due to earth fault. If your meter shows PFC when doing EFLI tests, you`ll see very low readings, in the order of a few amps. This is why an RCD is required, as an earth fault could well go undetected by the protective device!
HTH
KME
Where you are asked for max Ze, insert Ra on a TT system. 30-90 ohms typical. <10 suggests either:
1. an amazingly good rod
2. a parallel path, as suggested above.
Max Zs for mcb`s has no bearing on a TT system, as they are seriously unlikely to trip due to earth fault. If your meter shows PFC when doing EFLI tests, you`ll see very low readings, in the order of a few amps. This is why an RCD is required, as an earth fault could well go undetected by the protective device!
HTH
KME
On a TT, it ISN`T a Ze; its an Ra.
But yes, that is what goes in the box.
But yes, that is what goes in the box.
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Why not test the earth at the rod.
Batty
Batty
