When a motor starts your going to get high in-rush currents which exceed the normal operating current for a short time. To cope with that you would use a C or D type MCB, fine with that
Questions: If say the operating current of a motor is 20A what do you expect the in-rush current to be 20% more 30% more. Is there a Calculation or Standard? does this differ for 3ph and single ph Motors?
Also what do you base the cable CSA on? the running current or do you have to beef it up to cope with the in-rush current? TBH if you have to beef it up whats the point of the C of D type breaker after all its the cable your protecting.
Ta
Questions: If say the operating current of a motor is 20A what do you expect the in-rush current to be 20% more 30% more. Is there a Calculation or Standard? does this differ for 3ph and single ph Motors?
Also what do you base the cable CSA on? the running current or do you have to beef it up to cope with the in-rush current? TBH if you have to beef it up whats the point of the C of D type breaker after all its the cable your protecting.
Ta