I
ianherts
hi all ,pleas could some one help me with this:
a 12mm squared cable with 90 degrease thermosetting rubbers is to be used in conjunction with lighting,small power, data and fire alarms insullations. it is protected by a 40 A fuse to BS 88 part2 in an installation where loop impedence between lines of print where the fuse is installed is 0.14 olms. If the supply is 415V three phase, what will the protective short circuit be? Also determine the time for the current to raise the conductor temp to the permissible level.
this is what i have made it but not sure if its right:
I VL over Z A = 415v over o.12 olms = PSC 3.46 KA
T k squeared x S squeared over I squeared = (143x143) X (12x12) over 3460 = 0.245970129306
a 12mm squared cable with 90 degrease thermosetting rubbers is to be used in conjunction with lighting,small power, data and fire alarms insullations. it is protected by a 40 A fuse to BS 88 part2 in an installation where loop impedence between lines of print where the fuse is installed is 0.14 olms. If the supply is 415V three phase, what will the protective short circuit be? Also determine the time for the current to raise the conductor temp to the permissible level.
this is what i have made it but not sure if its right:
I VL over Z A = 415v over o.12 olms = PSC 3.46 KA
T k squeared x S squeared over I squeared = (143x143) X (12x12) over 3460 = 0.245970129306
