Lightning conductor for ametuer radio antenna mast - electrician says regular PVC sheated yellow green wire is ok from mast to earth rod

will regular 35mm green/yellow sheated earth be good enough to provide earthing for antenna mast while being exposed to the elements? How long will it last?

BS 7671 lists bare 25mm² copper as being sufficient for a buried earthing conductor for protection against both mechanical damage and corrosion (table 54.1)  - so you should be more fine with 35mm² PVC covered on that score. (Copper water pipes seem to survive the elements both buried and above ground almost indefinitely.)


If it's to be used as a lightning conductor though it'll have to survive lightning currents - others here will know more about that than me.


 

a corner of my house setup as a radio shack

I'd be a bit wary of converting a part of the house to TT while keeping the remainder as TN. When you have two different earthing systems it's imperative to keep them out of reach of each other - otherwise there can be a significant shock risk between items of metalwork connected to the two different systems. Metallic plumbing systems are one obvious way the boundaries between the two systems can be crossed (both initially and future channges) - but even things like Class I portable appliances and/or extension leads risks reducing the distance between the two systems in a way the electrical designer can't really guard against. I'll let the 'ham' types on here suggest the best solution to that problem though.


    - Andy.

will regular 35mm green/yellow sheated earth be good enough to provide earthing for antenna mast while being exposed to the elements? How long will it last?

BS 7671 lists bare 25mm² copper as being sufficient for a buried earthing conductor for protection against both mechanical damage and corrosion (table 54.1)  - so you should be more fine with 35mm² PVC covered on that score. (Copper water pipes seem to survive the elements both buried and above ground almost indefinitely.)


If it's to be used as a lightning conductor though it'll have to survive lightning currents - others here will know more about that than me.


 

a corner of my house setup as a radio shack

I'd be a bit wary of converting a part of the house to TT while keeping the remainder as TN. When you have two different earthing systems it's imperative to keep them out of reach of each other - otherwise there can be a significant shock risk between items of metalwork connected to the two different systems. Metallic plumbing systems are one obvious way the boundaries between the two systems can be crossed (both initially and future channges) - but even things like Class I portable appliances and/or extension leads risks reducing the distance between the two systems in a way the electrical designer can't really guard against. I'll let the 'ham' types on here suggest the best solution to that problem though.


    - Andy.