J
jonboy1
I have recently installed an earth spike within a garage and the Zs reading I got was 66 ohms and pf 3KA What is the permitted reading for a TT system within a garage?
Discuss Ze reading for TT system in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
Hey there.
A Ze (RA) reading of 66 ohms on a TT system is absolutely fine.
The accepted maximum is 200 ohms.
The maximum according to BS7671 is 1667 ohms, but a reading this high should never be accepted.
Cheers
I have recently installed an earth spike within a garage and the Zs reading I got was 66 ohms and pf 3KA What is the permitted reading for a TT system within a garage?
Thats a relief. We were going to throw a bucket of water over the rod to get a better reading. He he!
over 200 is classed as unstable as the reading may change with weather conditions. For instance if the spike is put in in winter the soil is wet but come mid summer after sunshine (not in scotland) the soil has dried and the resistance has risen.
If the reading is under 200 the liklyhood of the summer reading being over 1667 is low
Also need to keep in mind that
For additional protection x5 rcd tests on 30mA. So 150mA
50 divided by 0.15 = 333.33 ohms
Reply to Ze reading for TT system in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
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