J
Jodes
In "Advanced Electrical Installation Work" by Trevor Linsley, he says that an earth electrode rod that is 1m deep will typically have a resistance of between 10 and 200 ohms. Given that fault currents can supposedly, momentarily, be in the order of 1000's of amps, this makes me scratch my head:
Let's say 1000 amps and 10 ohms, that would be a p.d. of 10kV. But given a 240v supply, the highest fault current possible would be 24A. So a short between live and earth would bring just about every bit of metal up to 240v, potentially without a single fuse blowing!! (Ignoring RCDs)
What am I missing?
Let's say 1000 amps and 10 ohms, that would be a p.d. of 10kV. But given a 240v supply, the highest fault current possible would be 24A. So a short between live and earth would bring just about every bit of metal up to 240v, potentially without a single fuse blowing!! (Ignoring RCDs)
What am I missing?