Determine the minimum conductor size for a final sub-circuit supplying a single-phase 230V power circuit protected by a 20A Circuit breaker. The circuit consists of TPS cable with copper conductors in a roof space. The route length of the circuit is 38m, and the voltage drop in the existing consumer's mains is 3V.
Voltage drop permissible in the final subcircuit:
11.5 volts- 3 volts=
8.5 Volts
1 Phase Vc= Vdx1000/(LxI)
= 8.5 x1000/(38x20)
= 11.18m.v/a.m
3 Phase Vc= 1 phase Vc/1.155
=11.18/1.155
= 9,68m.v/a/m
TPS cable with copper conductors should use Table 42; Column 6 (75 Degrees-max)
Answer: 4mm2 with a 6.49m.v/am rating.
Correct answer on the system is: 2.5mm2.
Is there and error?
Minimum size cable as per table