On 7/4/2011 9:45 AM, leza wang wrote:
my home is like 70 or even more years old (not sure really). I want to
know if i should upgrad the wiring. the electrical panel shows i have
100 amp. I have been told if i have knob 2 wiring then i should change
it to 3 knob wiring. My question, how can I know if i have 2 knob
wireing or 3? in the main floor, i have all power outlet with 2 holes
(+,-) upstair I have power oullet with 3 holes (+,-, ground)
Thanks a lot.

OK Leza, here's the deal. A 70+ year old house can, and probably does
have many types of wiring, possibly including Knob & Tube. The fact that
you have a 100 amp service is a good indicator that some upgrading has
already been done. Older wiring, regardless of type, will be less safe
than current wiring types. This doesn't necessarily mean you should run
out and have it all replaced. It would be helpful if you could post some
pictures of your electric service, the cables entering the service
panel, and any wiring you can see in your attic. With the pictures, a
better evaluation of you situation can be made.