greensparky
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- Aug 29, 2008
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Hi guys I hope there is some one out there that can answer my question, I am learning to do electrical testing, and for practice I did a periodic inspection for a friend to see if it needs any work done before it is tested by an experianced tester, the test was on a mot station and mechanical work shop with overhead lines and is earthed on a TT system, I did an earth electrode test and got a reading of 6.61 ohms so with the R1+R2 measurments on each circuit the results are all over 7 ohms, this is where I start to get confused, because the regs say that a measurement of below 100 is OK for an RCD to opperate, Great but what about the circuit breakers these measurments are to high. so what is the presidence if you use an RCD does it not matter about the earth loop inpeadence measurment for the circuit breaker measurement ? I have looked through the regs and gn3 and another couple of books i bought but I can not find an answer does any one know where I can find out cheers.