Table 41.1 Assumed Touch Voltage

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ProMbrooke:

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?  


From IEC 61200-413

Table 41.1 refers to MAXIMUM disconnection times.


NOTE 1 says that disconnection is not required for protection  against electric shock, but may be required for other reasons such as protection against thermal effects. Also, a 30mA R.C.D. usually protects against dangerous electric shocks in most cases, due to its swift operating action.


Z.


 

Right.


Note 1 only applies to DC touch voltages between 50 and 120 volts.


RCDs can and do fail and should not be sole means of achieving ADS.


 

Zoomup:

ProMbrooke:

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?  


From IEC 61200-413

Table 41.1 refers to MAXIMUM disconnection times.


NOTE 1 says that disconnection is not required for protection  against electric shock, but may be required for other reasons such as protection against thermal effects. Also, a 30mA R.C.D. usually protects against dangerous electric shocks in most cases, due to its swift operating action.


Z.


 

Right.


Note 1 only applies to DC touch voltages between 50 and 120 volts.


RCDs can and do fail and should not be sole means of achieving ADS.