r, x, & z - cable calcs

[Rockingit]

Interested to hear how different people approach doing loading / vd calcs for larger size single core cables in a 3ph situation - ie 3 separate L1, L2, L3 & N cores above say 95mm.

 

[Spoon]

For cables that have 3 figures: r (resistive) x (reactive) z (impedence). I use the z value for mV/A/m as a general rule of thumb.

 

[pc1966]

Unless you have figures for the supply Z (e.g. transformer, etc) decomposed in to R & X, etc, and it is comparable to the cable figures then simply using cable Z makes sense for VD.

For I2R heating losses then R, of course!

Edit: @Julie. is probably the best one to ask for this!