"Attached (Contact Resistance on Compact NS_NSX MCCBs.pdf), you will find the new procedures for measuring the contact resistance. The procedure can be summarized as follows:
Pole resistance measurement:
1. Manually operate 5 times the circuit breaker to the OFF and then to the ON position (without current)
2. Apply test current across one pole for at least 30mins
3. Record the millivolt drop and calculate the resistance (R = U / I)
4. Take 3 consecutive measurements operating each time the device and calculate the average
5. Repeat for each pole
Concerning the acceptable value, values less than or equal to 1.3 times the reference value are acceptable in view of measurement uncertainties."
Pole resistance measurement:
1. Manually operate 5 times the circuit breaker to the OFF and then to the ON position (without current)
2. Apply test current across one pole for at least 30mins
3. Record the millivolt drop and calculate the resistance (R = U / I)
4. Take 3 consecutive measurements operating each time the device and calculate the average
5. Repeat for each pole
Concerning the acceptable value, values less than or equal to 1.3 times the reference value are acceptable in view of measurement uncertainties."
Released for:Schneider Electric Nigeria
