Grid cable support (5)
I believe the answer is:
pylon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grid cable support</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pylon that I've seen before include "Grid cable support" , "Bearer of cable" , "Tower for carrying power line" , "Steel structure carrying cables" , "Electric grid support" .)