Shack wiring and static protection

[eddie_ce]

If the supply had been changed in the street and the outer lead covering not connected to neutral and the households not converted that would be illegal and extremely dangerous as some of the houses in my vicinity may not have their gas and water pipes bonded to the incoming earth. My home was like that when we moved in about 30 years ago.

I'm not sure if this comment applies to post #12. The point I was trying to make is that the fact that your main earth is connected to the lead sheath does not automatically imply you still have a TN-S system. It would indeed be illegal to leave the lead outer sheath floating as your MET would be hanging in the air as far as the DNO is concerned.

If however, for one of the reasons stated in post #12 the outer sheath of your supply cable is no longer a continuous earth conductor back to the transformer but en route has been connected to the PEN conductor by definition you no longer have a TN-S supply although under normal conditions you still have a fully functional earth conductor. AFAIK the DNO is under no obligation to inform you of this change.

I do not wish to hijack this thread or labour the point. I am merely trying to point out potential pitfalls.

Perhaps somebody more qualified than my self will comment.

[stuarth]

Having your MET connected to the outer sheath of you incoming cable does not mean you have TNS, there may be a section of the cable between your house and the substation where the neutral and earth share a common connection. There should be Protective Multiple Earths on the cable into you house, but the break in the shared NE cable could be close to your house, so there may be few of those PMEs to keep your mains earth connection close to ground potential.

The essence of the wiring rules and the RSGB document is that in your shack that there should be either a mains earth, or an RF earth, but not both - unless they are securely bonded together, i.e. at the same potential. This even applies if the radio equipment is battery powered; if it has exposed metalwork connected to the RF earth, there should be no exposed metalwork connected to mains earth in the same shack.

Stuart

[crackle]

So it looks as if I will need to disconnect the RF earth from the antenna pole as it connects via the braid to the shack (bedroom), and remove the RF earths in the shack as I have a central heating radiator and obviously the mains in there also.
I cant say it makes me feel safer.

Thanks everyone for your contributions, it will be interesting to see if this helps prevent the output MOSFETs from blowing.

Mike