Reduced ground question

[willerjim@msn.com]

I am a general contractor. We are remodeling small residence built in the 40's. All wire is older romex with smaller- guessing 14 gauge- ground wire. We are tapping into some of this wire with new romex that has the heavier ground. The question is - can you tie into these lighter gauge grounds with the newer heavier gauge romex grounds? I have heard from some electricians that you cannot. What say you? Any experience with this issue? Is it even an issue. It will all be grounded with greenies, but I want to make sure.

 

[glene77is]

WillerJim,
...
This may involve a local interpretation,
which the Electrical Inspector's office can help.
I have called our code enforcement several times,
and found ours very helpful.
...
Practically speaking, try looking at this way,
will the EGC trip the OCPD under ground fault conditions ?
That is, will the #14 EGC pass enough current during the moment of fault,
so as to trip the CB ?
I think you will say 'Yes'.
...
If in doubt about code issues, install GFCI recepticals,
which do not require any EGC at all.
The NEC handbook has a good description of how these function,
which may make you a believer.
...
Just curious, what kind of insulation does your 'romex' have?
Is it rubber, with paper wrapping each conductor,
with a greasy paper sheathing over all this?
If so, be certain not to bend the wire, as the insulation may fall off !
Try this method, which I use:
Slide a new JB over the end of the old 'romex',
then strip and crimp splice (with butt splices).
Paint any exposed wire with liquid rubber.
Just a suggestion from my experience.
...
Your comments are welcome.
...

 

[mull982]

I would thing that as long as the existing #14 ground in the existing romex is large enough per code for the existing OCPD that the existing romex circuit is connected to, and all the new romex connections will be fed off of the same romex circuit then I would not think there is any issue with doing this.

 

[charlie]

In the #12 and #14 sizes (not sure about #10), the grounding conductor was #16. It was fine until some jack-legs and DIY started using the grounding conductor for a neutral and burning up stuff. After that, the grounding conductors were up-sized to the same size as the rest of the conductors through #10.

 

[c2500]

Out of curiousity, are you sure of the house age? In Greenville, SC, I have never seen grounded NM in anything earlier than the late 50's, and normally it was the late 60's before it showed up. We are blessed with an abundent supply of oily cloth sheathed NM. Where are you located? By the way, does anyone know when the reduced grounds were eliminated?

c2500