Discuss What’s your countries Max Zs Values? in the UK Electrical Forum area at ElectriciansForums.net
The Table 41.3 in the BBB is for the MCB at Umin and no allowance for cable temperature, so in that case we have for 32A B example:Interesting theres quite a disparity there and we are supposed to only allow 80% of the stated values too!
I have never been happy with the use of an RCD as your primary protection.Well if we use an RCD it is acceptable to allow a Zs of 1667 ohms so pretty high really.
Agreed. Good example of what the regs at times allow but what in reality would amount to poor (in this case even bad) work practice. Add to that the fact rod resistance can vary considerably.Well if we use an RCD it is acceptable to allow a Zs of 1667 ohms so pretty high really.
While the UK regs allow for 1667 ohm in theory (i.e. 50V touch potential at 30mA) they also state that earth rod impedances above 200 ohms are likely to be unstable in practice.Agreed. Good example of what the regs at times allow but what in reality would amount to poor (in this case even bad) work practice. Add to that the fact rod resistance can vary considerably.
Reply to What’s your countries Max Zs Values? in the UK Electrical Forum area at ElectriciansForums.net
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