Following a hurricane I had to rewire a beach cottage(about 45 years old). I put in a new meter pan, circuit panel(200 amp) and made new connections to upstair existing wire that I could not pull(old heart pine walls and ceilings). On the advice of Rex Cauldwell’s book(wiring a House) I purchased a suretest circuit analyzer to check all circuits. Everything checked fine except in receptacles of internal wall old wire(12-2 with what looks like a 16 or 18 ground wire) I generally tested on the N-G voltage of the analyzer- 4 to 6 volts of leakage with a resistance of about 1.5 to 2.0 ohms on the ground wire. At the beginning of these circuits there was little leakage at my connection of new 12-2 with g  and very little resistance so I think my panel is O.k. Is this a problem of major concern. It may have been this way for years before I tested with the suretest. What do I need to check further? Thanks for anyone’s help.