John John wrote:
My house was built in 1977 and even then the power company would not
have connected without earthing at the meter. In this country we have
long ago abandoned knob and tube wiring...

And that requirement is sufficient only for human safety. Power
company cares not whether your appliances have any protection - or are
even damaged every year. They are only concerned about earthing for
human safety.

Chances are your earthing is not sufficient for transistor safety.
Did you read many posts and technical reasons for enhanced earthing?
Most 1977 homes have earthing woefully insufficient for transistorized
appliances AND have virtually no 'whole house' appliance protection.
Does you telephone service have properly earthing protection - that was
only introduced in the mid 1980s? Again, those many older telephone
installations were only earthed for human safety - not for today's
phones. Did you learn from previous posts to discover if your earthing
is sufficient? Or did you just know and therefore post disparagement
accordingly?

Chances are that a house built in 1977 needs its earthing for all
utilities upgraded. Chances are your earthing is the equivalent of
knob and tube wiring. Did you read those posts or just *assume* 1977
earthing will always be sufficient? You have much learning to do.