My house was built in 1929. The original wiring is knob & tube (2-wire with no ground). The electrical service was upgraded to 200 amp service, but the old 2-wire outlets remain. They are supplied by a fuse box.
I need to add ground to at least one of the 2-wire outlets. Is there a way to ground the fuse box which will ground all 2-wire outlets? I think just grounding one outlet (ground rod) is not recommended (against code?).
Originally posted by dr-art: My house was built in 1929. The original wiring is knob & tube (2-wire with no ground). The electrical service was upgraded to 200 amp service, but the old 2-wire outlets remain. They are supplied by a fuse box.
If you have a new 200A service why are these circuits supplied by an old fuse box?
quote:
Originally posted by dr-art: I need to add ground to at least one of the 2-wire outlets. Is there a way to ground the fuse box which will ground all 2-wire outlets?
NO, grounding the fuse box (which I suspect is already grounded) will NOT ground the branch circuits if they are only 2-wire.
quote:
Originally posted by dr-art: I think just grounding one outlet (ground rod) is not recommended (against code?).
NO, a grounding electrode DOES NOT create or provide a "ground", as in the third hole in a receptacle. Not even close.
The ONLY ways to ground an non-grounding circuit are: - to run a ground wire back to the panel, or back to part of the grounding electrode system which is inherently bonded to the service neutral at the main panel. THIS is your safety ground, NOT the ground rod.
- or to run a new circuit to the receptacle.
Posts: 204 | Location: NYS | Registered: Nov 13, 2007
Thanks. The 200 amp service was installed on its own and never connected to the fuse box. The previous owner just left the old fuse box in and seldom, if ever, used the small number of outlets that it serves.
Running the 2-wire outlet I need to be grounded back to the service neutral at the main panel would be a huge undertaking (lots of impediments). Can I run a new 3-wire cable from an existing 3-wire outlet (connected to the 200 amp service box), as long as the capacity of that circuit is not compromised? That would be a significantly easier, though still cumbersome, fix.
I wonder if I can run a ground wire from an existing grounded outlet to an un-grounded outlet? Would that provide grounding for the 2-wire receptacle through the 3-wire receptacle circuit?
Either of your suggestions would work and be legal. I personally do not like the running of a ground wire though. I would run a new grounded cable from an existing circuit given the opportunity. If you do, be SURE to cap off the old wires very securely.
Posts: 204 | Location: NYS | Registered: Nov 13, 2007
you should make certain that it is on a circuit breaker. we bought a house that was built in 1925 and could noy even get homeowners insurance without having that beyond that...you should have it replaced. the wiring is old, cloth covered, and not designed for the kind of loads that we have electrically these days the only thing we didn't do here is the lighting,due to the low demand it requires... knob and tube is not a do it yourselfer type of project know your limitations and consult a professional
