•  Line losses

•  Loss in conductors/cables where lowersize conductors are used. This causessags and temperature rise in conductorswhich further aggravate the loss,

•  Loss in higher loaded phase wires due to unbalanced loading,

•  Loss due to current in neutral for cases or unbalance where neutral wires of lowersize are used (like 3 ½ core cables, andneutral wires of size lower than phasewires),

•  Loosening of strands (in multi-strandconductors like ACSR, AAC, AAA, etc.). 

•  Loss in mid-span joints

(or any joint) and at

terminations

•  Contacts of joints due to improper installation and looseness,

•  Contacts of joints due to inadequatesurface area of contact.

•  Loss in transformers

(typically DTs)

•  Loose connections at bushings,

•  Bend in jumpers at connectors where the strands are not tightly held,

•  High no-load loss depending on type of core used, 

•  High no-load loss in repaired transformers where the core has not been properly tightened,

•  No load loss in case a large number of lightly loaded DTs,

•  High copper loss for transformers operating at sub-optimal loading which is not commensurate with the designed optimal loading. 

•  Loss in service cables

and connections

•  Undersized service cables,

•  Loss in joints of service cables at the poles/junction boxes,

•  Use of inappropriate fasteners without spring washers at the crimped joints.

•  Loss due to high

impedance faults

•  Tree touching, creepers, bird nesting,

•  Insulator breakages and tracking on surface of the insulator.

•  Loss in re-wired

fuses/jumpers

•  Loose connections,

•  Inadequate size of fuse wires - often a source of hot spots.