IEC 60364 Table 48A

 

Higher rated circuits has a much lower R1+R2, producing voltage drop on the transformer and in turn a lower touch voltage whereby disconnection can be longer without worry of physiological harm. 

Really? You are saying that the Voltage droop will be more than say 200 Volts leaving a maximum "touch Voltage" of 50 or less. ? You may wish to re-think that assumption. If the Voltage droop is too much the current flowing may be insufficient to operate a fuse or circuit breaker and the fault current left flowing for a very long time..


And if there is no R2 what happens?


I have a customer whose elderly father has cut through the flex of an electric hedge trimmer twice. On both occasions the new garage unit's M.C.B. and R.C.D. tripped off making the situation instantly safer.


Imagine just what might happen if somebody is using an electric appliance/tool outside and damages the flex. There is no R.C.D. protection. The tool is a Class 2 type so no C.P.C. exists. The bare live (line) wire becomes touchable and the person is standing on the ground, perhaps barefooted on the lawn, or perhaps they are touching metal railings with their other hand.


Would the protective M.C.B. trip off? Will the 13 Amp fuse in the appliance plug open?



I certainly would prefer R.C.D. protection. In this case the garage R.C.D. runs in series with a house R.C.D.


Z.


 

 

Higher rated circuits has a much lower R1+R2, producing voltage drop on the transformer and in turn a lower touch voltage whereby disconnection can be longer without worry of physiological harm. 

Really? You are saying that the Voltage droop will be more than say 200 Volts leaving a maximum "touch Voltage" of 50 or less. ? You may wish to re-think that assumption. If the Voltage droop is too much the current flowing may be insufficient to operate a fuse or circuit breaker and the fault current left flowing for a very long time..


And if there is no R2 what happens?


I have a customer whose elderly father has cut through the flex of an electric hedge trimmer twice. On both occasions the new garage unit's M.C.B. and R.C.D. tripped off making the situation instantly safer.


Imagine just what might happen if somebody is using an electric appliance/tool outside and damages the flex. There is no R.C.D. protection. The tool is a Class 2 type so no C.P.C. exists. The bare live (line) wire becomes touchable and the person is standing on the ground, perhaps barefooted on the lawn, or perhaps they are touching metal railings with their other hand.


Would the protective M.C.B. trip off? Will the 13 Amp fuse in the appliance plug open?



I certainly would prefer R.C.D. protection. In this case the garage R.C.D. runs in series with a house R.C.D.


Z.