A yw polisi cynllunio Llywodraeth Cymru (i) yn ei gwneud yn ofynnol neu'n (ii) argymell bod llinellau trosglwyddo a dosbarthu trydan yn cael eu gosod o dan y ddaear (a) mewn parciau cenedlaethol, (b) mewn ardaloedd o harddwch naturiol eithriadol, (c) mewn tirweddau cofrestredig o ddiddordeb hanesyddol eithriadol ac arbennig, (d) ar arfordiroedd treftadaeth ac (e) mewn ardaloedd tirwedd arbennig?
Planning Policy Wales states the Welsh Government’s preferred position on new power lines is that, where possible, they should be laid underground. However, it is recognised that a balanced view must be taken against costs which could render otherwise acceptable projects unviable. Where undergrounding of lines is not possible or applicable, proactive engagement with energy companies and the public to mitigate the visual impact of any potential new transmission lines should take place.