T
thebassman
Hi All
I was called to a farm to a fault in there pumping system for there water supply, this consists of a pump some 300 metres away from the farm the pump is controlled via a contactor, the coil is controlled by the float switch at farm storage tank. The fault is when float switches call for water contactor operates but when float switch opens the contactor stays in, we replaced contactor so this is a new contactor. with float switch open i measured a volatge of 120v on switch wire from float switch. So i tested the cable which is a 2 core swa and got insulation of greater than 100mOhms between core and to earth. So as you see there seems to be no leakage in the cable i also connected cable to 240v and did loop impedance test this was high at 7.37ohms, i would have thought that if there was any leakage between core appplying 230 would have caused mcb to trip. I have also disconnected float which and just linked out cable end and the same thing happen i have ran out of ideas for this one spent a a whole day at this tramping down through a field about 20 times in the rain.
Any thoughts on what could be problem i am convinced its the cable its been in 23 years and is one continuous lenght no joints in it
Danny
I was called to a farm to a fault in there pumping system for there water supply, this consists of a pump some 300 metres away from the farm the pump is controlled via a contactor, the coil is controlled by the float switch at farm storage tank. The fault is when float switches call for water contactor operates but when float switch opens the contactor stays in, we replaced contactor so this is a new contactor. with float switch open i measured a volatge of 120v on switch wire from float switch. So i tested the cable which is a 2 core swa and got insulation of greater than 100mOhms between core and to earth. So as you see there seems to be no leakage in the cable i also connected cable to 240v and did loop impedance test this was high at 7.37ohms, i would have thought that if there was any leakage between core appplying 230 would have caused mcb to trip. I have also disconnected float which and just linked out cable end and the same thing happen i have ran out of ideas for this one spent a a whole day at this tramping down through a field about 20 times in the rain.
Any thoughts on what could be problem i am convinced its the cable its been in 23 years and is one continuous lenght no joints in it
Danny