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Deleted member 9648
Doing a PIR on an installation and one of the DB's is an old crabtree C50 3phase board ,with the old white lettering breakers which are M3 rated....now I've a measured single phase PFC/PSC of 1.7ka...which gives a max phase-phase result of 3.4ka.
All of the final circuits from the DB are single phase ,so it seems to me highly unlikely that these mcb's would be subjected to the max 3.4ka fault current on the load side....would I be correct in that, or should I code it as the M3 breakers will not meet the max measured PFC??
(cant rely on upstream devices in this instance as the guidance is that only a 1361 type2 fuse rated at max 100A will raise the breaking capacity of final circuit mcb's to 16ka....this DB is supplied from bs88 100a fuses with 200a at the head)....Any thoughts?
All of the final circuits from the DB are single phase ,so it seems to me highly unlikely that these mcb's would be subjected to the max 3.4ka fault current on the load side....would I be correct in that, or should I code it as the M3 breakers will not meet the max measured PFC??
(cant rely on upstream devices in this instance as the guidance is that only a 1361 type2 fuse rated at max 100A will raise the breaking capacity of final circuit mcb's to 16ka....this DB is supplied from bs88 100a fuses with 200a at the head)....Any thoughts?
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