P
peterhardacher
Hi am currently employed as testing and inspection on a industrial site just wondered if you could give me some advise
What it is I got a 110 kw motor 180 amp 100 m run full load now I got a 75 mm cable supplying it . I have checked table 4d4a in the regs as it is 3 core armoured . Ref method E . According to this it says am allowed 207 amps without correction factors .
I have also done a cable calc 110000 w / ( 1.73 * 400v ) = 158 amp without power faction correction is this correct ?
I have been in Internet on cable calc program's for cable manufacturers which is telling me 75 mm
Now what it is the cable is protected by a HRC motor fuse 315m 355a according to Ib < In < Iz the fuse size is greater than the cable max amps
Also what concerns me is local to motor the 75 mm goes to a JB and reduces to 25mm I think because there is a lack of space for the bigger cable as the motor has other things around it . Now a 355 amp defo does not protect that cable in case of overload
Now one final thing this motor goes through a variable speed drive but even if it was set at 80 % I still have the problem of oversized fuse . Now I pointed this out to my boss he says its acceptable but I think he's wrong and as am signing the sheets I would great fully apreciate your professional advise on this thanks
What it is I got a 110 kw motor 180 amp 100 m run full load now I got a 75 mm cable supplying it . I have checked table 4d4a in the regs as it is 3 core armoured . Ref method E . According to this it says am allowed 207 amps without correction factors .
I have also done a cable calc 110000 w / ( 1.73 * 400v ) = 158 amp without power faction correction is this correct ?
I have been in Internet on cable calc program's for cable manufacturers which is telling me 75 mm
Now what it is the cable is protected by a HRC motor fuse 315m 355a according to Ib < In < Iz the fuse size is greater than the cable max amps
Also what concerns me is local to motor the 75 mm goes to a JB and reduces to 25mm I think because there is a lack of space for the bigger cable as the motor has other things around it . Now a 355 amp defo does not protect that cable in case of overload
Now one final thing this motor goes through a variable speed drive but even if it was set at 80 % I still have the problem of oversized fuse . Now I pointed this out to my boss he says its acceptable but I think he's wrong and as am signing the sheets I would great fully apreciate your professional advise on this thanks
