I want to upgrade the plugs to ground type in a house built in the 1960's.The old romex has a reduced size (#16 I think)grounding conductor in the cable that is wraped around the romex and pinched in the connector or under the clamp of the metal box. What is the correct way to convert to ground type plugs in this case? Is the reduced size ground wire in the romex OK to use for grounding?
There is nothing wrong with the reduced size grounding conductors. The reason the grounding conductors were required to be made to match the circuit conductors in the smaller cables (#10, #12, and #14) is that too many DIYs and jacklegs were using the grounding conductors for circuit conductors. I have even seen the grounding conductor used as a phase conductor where a single-phase switch was converted to a three way without replacing the cable (they just taped up the grounding conductor and connected it to the switch and light fixture).
Table 250.122 requires a #14 copper grounding conductor for a 15 amp overcurrent device protected circuit...so how can the #16 grounding conducter in the old romex be used for grounding when upgrading a house to grounded plugs?Is there an exception somewhere?
Re: romex from the 1960's#89617 10/10/0410:27 AM10/10/0410:27 AM
BigB, the smaller wire works just fine for fault clearing the same as smaller wire works for fault clearing on larger circuits. Remember that the fault will be cleared before the current will destroy the grounding conductor or table 250.122 would not be valid.
Depending upon where you are working, you may or may not be "grandfathered". You need to check with your local laws and ordinances. In Indiana, you are permitted to continue to wire an addition with the Code that was in force when the home was built.
If it met the code in effect at the time of installation shouldnt it be Grandfathered in?I was always under the impression that the code was not retroactive but, assuming things can cause lots of trouble.
Re: romex from the 1960's#89623 10/12/0405:42 AM10/12/0405:42 AM