I need to describe what I want to my wife. I want to ask about rewiring the house and to explain the concept of earthing. I've tried Thai2English, but not sure that is what I need. TIA

I believe the term you are looking for is, สายดิน, saai din.

Just because you know what term to use doesnt mean she will understand, best talk to a builder.

Just to make sure you know what you call "earthing" may be known here by the American term "grounding" and a "earth return connection" may be called a "ground wire" by some of the local electricians that learned it that way from a Thai technical school with an American ciriculum.

Thanks guys