The correct link cable with armouring, there are versions which are not armoured. The cable must be clipped up to the top of the heel-board above the prop-shaft, especially the non-armoured versions. If this is not done compression of the suspension can cause the prop-shaft to wear through the cable insulation with predictable results ... (Image Motaclan/Leacy)
... as this from 'Mike' on the MGOC forum shows:
When I replaced the POs 12v battery with twin 6v I fitted a new link cable (unarmoured as that was all that was available at the time). Although the armouring was still in place on the car the new cable came with clamps already fitted so I removed the old armouring and just pushed the cable through the holes in the sides of the battery boxes. Some time later something made me remove the cable and check it and the insulation had worn part way through. I put it through a length of plastic waste pipe that was supported by the holes in the sides of the battery boxes but even that subsequently showed the underside as having been rubbed by the propshaft.
When replacing that with armoured (because of corrosion at a clamp) I re-used the original support clip under the battery shelf and above the prop-shaft to hold it well out of the way. Even though wear and shorting is unlikely to be an issue with armoured it is likely to make a noise:
Typical installation, with strips of red sheathing off an old Metro cable indicating the polarity. This was an earlier non-armoured cable, subsequently replaced with armoured when one clamp became heavily corroded.
Massive growth around the link cable terminal on the right-hand battery. It was only when I replaced the cable that I noticed a crack in the casing by this terminal. Probably the cause, repaired using Araldite it has run for another 12 months without developing again and only a very slight reduction in electrolyte level.
The new armoured cable going to the terminal at the top left, as annoyingly it wasn't long enough to go to the other corner as on both the previous and the original link cables. The extended main battery cable from the cut-off switch now goes to the further terminal, the battery having been rotated 180 degrees. This means that the 12v terminal is now very close to the clamp bracket (circled) so care needs to be taken to maintain adequate clearance. But as both terminals on the left-hand battery are 'live' with respect to earth this is no different to the original orientation. As all the cables are black I was bothered about incorrect connection right back when I fitted twin 6v batteries. I happened to have a length of red cable from somewhere, so I cut the insulation off that in a spiral and used two lengths to wrap round the main 12v cable ...
... and the +ve end of the link cable.
