
Power Cable 173
in both conductors concentrates near their adjacent faces as shown in Figure7.6. The
virtual effect of such current concentration is to increase the effective resistance of
the conductor working in proximity of other conductors. The combined skin and
the proximity effects are generally accounted for by multiplying factors listed in
Table7.7 for various conductors at 60 Hz and 50 Hz, from which
R
ac
= R
dc
× Skin and proximity factor from Table7.7 (7.7)
7.6 CABLE DESIGN
The cable design primarily requires selecting the conductor size with required
ampacity at the operating temperature that will also meet the v