Answer Happy

Question 6 a) A 50A BS88-2 HRC fuse is used to protect a 220V single phase equipment against short circuit fault. The circuit is wired by 10mm² 1/C PVC copper cable. Given that: • The cable length measured from the fuse to the equipment is 60m • The short circuit current measured at the fuse is 700A • Resistance of the 10mm² cable is 2.2m/m • K factor of the 10mm² cable is 115 • The time/current characteristic of the BS88-2 HRC fuse is shown. 60 m 50 A LO N -Foo Ise=700 A Figure B4a i) Determine the magnitude of the short circuit current if the short circuit is occurred at the load side of the installation. (4 marks) ii) By using Adiabatic equation, determine whether the cable is thermally protected by the fuse. (4 marks) iii) Calculate the touch voltage during fault (2 marks)