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Table 41.1 Assumed Touch Voltage
Former Community Member
I am a bit confused by this. Why do the disconnection times in Table 41.1 appear to be based on a touch voltage of 100 volts rather than a touch voltage of 125 volts?
For example, 110% of 230= 253 volts. Assuming L and PE are of the same size and material, indirect contact touch voltage is 126.5 volts. Would 0.33 seconds not appear more realistic?
If they are not totally reliable then use two in series to half the perceived risk.
No, it's much better than that. Assuming that whatever causes one to fail does not affect the other one, i.e. failures are independent of each other, the risk is squared. So if the failure rate of one is 7% (about 1:14) the failure rate of both is 0.5% (1:200).
Oh ek! I knew that I should have gone to those maths' evening classes.
If they are not totally reliable then use two in series to half the perceived risk.
No, it's much better than that. Assuming that whatever causes one to fail does not affect the other one, i.e. failures are independent of each other, the risk is squared. So if the failure rate of one is 7% (about 1:14) the failure rate of both is 0.5% (1:200).
Oh ek! I knew that I should have gone to those maths' evening classes.
