ECN Forum Forums Code Related Discussion NEC & other Code issues Reduced grounding wire in NMC

Once upon a time there was no requirement for residential NM to have an EGC. Eventually, there was an NEC requirement (early 1960's) for branch circuits to have an EGC, but not until a few years later did the NEC tighten the requirement by specifying a minimum gauge for it. Before that manufacturers could and did make NM with a reduced gauge EGC. The most likely reason why is probably the most obvious - cost.