Aluminium ground system suitability for ham radio station

I have been asked a few times about my article Implementation of G5RV inverted V using high strength aluminium MIG wire, and conversations ran to the suitability of the wire to a radial system on Marconi type antennas.

Firstly, a progress report on the antenna, no news to report and that is good news, there have been no issues so far. Inspection of connections without disassembly has not shown signs of corrosion or fatigue.

So, if the ongoing trial reveals no problems with aerial conductors, I cannot see why it would not also be suited to elevated radials.

I would not bury aluminium wire as part of a power earthing system, lightning protections system or RF ground.

The two relevant US ‘standards’ state:

  • NEC: Aluminium electrodes shall not be permitted
  • NFPA-780: Aluminum shall not be used where contact with the earth is possible or where rapid deterioration is possible.

Those standards exclude use of aluminium ground electrodes for power earthing and lightning protection.

Now you might argue that insulated wire can be an effective conductor for buried radials, effective at RF, and that is true.

The matter of relevance is why is aluminium prohibited by those standards? It seems related to corrosion, and a conducting material prone to attack by acid soils might not exist for very long.