- Reaction score
- 984
You can not do R1 +R2 = Zs -Ze as for the parallel paths
If we are talking domestic, mostly twin and earth cabling
You can calculate this fairly accurately, if your in any doubt, if you take your ZS then remove your ze, then have an approximate idea of cable run you can look at the resisstance per meter
Rings are easier to confirm with the exception of a long spur from the furthest point
i only usually find parallell paths in a domestic setting on immersion circuits/ring circuits with heating/boilers etc on and houses with supp bonding
Commercial/ind jobs using a lot of metal work are of course
another matter
Obviously r1 and r2 on TT systems domestic or otherwise i would measure in all circumstances