It's me again -- the pest ;-)
On the general inspection report for the house we're looking at buying, there's a note about the house's electrical:
Some three prong outlets did not test properly grounded. This may be an indication that the wiring in the walls is the older ungrounded type. We recommend considering upgrading to grounded type wiring for safety enhancement.
How big of a safety concern is this? Is there any other explanation for faulty ground tests? What corrective action would be necessary? I'm concerned that fixing this would require the entire electrical lines to be replaced... If so, any thoughts on how expensive that would be? I'm guessing quite a bit.
What's strange is that the report does mention that a ground is present on the main panal:
Grounding system is present. The grounding electrode was buried and not fully visible at the time of our inspection. Wood screws are used to secure the dead front cover to the panel. This is improper because they have sharp ends and can damage the protective coating in the wires inside the panel. We recommend installing proper screws.
The inspection report also recommended adding GFCI outlets. Would that help at all?