just a quick question while i was doing some calculation a ring main on a tns system
Wired in 2.5mm twin and earth ( r1+r2 value 19.51 m.ohm/M )
Approx length of run 35 Metres
Type B circuit breaker max E.F.L. 1.16ohm (on site guide)
Zs = 0.8 + (0.68 ) = 1.48ohm (exceeding max value for breaker)
is it the fact that circuit will have r.c.d. protection or because its a 'ring' mean this circuit is ok even though the e.f.l is high? or is it not ok and ive missed something?
Wired in 2.5mm twin and earth ( r1+r2 value 19.51 m.ohm/M )
Approx length of run 35 Metres
Type B circuit breaker max E.F.L. 1.16ohm (on site guide)
Zs = 0.8 + (0.68 ) = 1.48ohm (exceeding max value for breaker)
is it the fact that circuit will have r.c.d. protection or because its a 'ring' mean this circuit is ok even though the e.f.l is high? or is it not ok and ive missed something?