G
glasgospark
question probably how would you test resistance of electrode on a tt system on a stand by generator.
firstly ask permission and notify the customer that the standby generator will be locked off thus premisses will be with out a back up power supply.
generator isolated lock it off and retain key
disconnect earth from generator
test equipment- earth electrode resistance tester
question may state length of existing electrode say 3m
so, current electrode must be put in 30 meters from the electrode under test and between the 2 is a potential electrode.
tester connections C1 and P1 connected to EUT c2 -current electrode p2 potential electrode
make a test at this point record reading
move potential electrode 3meters towards current electrode make a test and record reading
then move it 3 meters towards EUT from the initial point make test record reading
take the average of all 3 and each reading should be within 5% of the average if they are then the average of all 3 is the reading that is recorded.
disconnect test equipment re connect earth to generator
Read more: http://www.electriciansforums.net/i...ns/68577-2394-2395-exams-2.html#ixzz2OPF9LV92
firstly ask permission and notify the customer that the standby generator will be locked off thus premisses will be with out a back up power supply.
generator isolated lock it off and retain key
disconnect earth from generator
test equipment- earth electrode resistance tester
question may state length of existing electrode say 3m
so, current electrode must be put in 30 meters from the electrode under test and between the 2 is a potential electrode.
tester connections C1 and P1 connected to EUT c2 -current electrode p2 potential electrode
make a test at this point record reading
move potential electrode 3meters towards current electrode make a test and record reading
then move it 3 meters towards EUT from the initial point make test record reading
take the average of all 3 and each reading should be within 5% of the average if they are then the average of all 3 is the reading that is recorded.
disconnect test equipment re connect earth to generator
Read more: http://www.electriciansforums.net/i...ns/68577-2394-2395-exams-2.html#ixzz2OPF9LV92