Been trying to figure out when a grounding bushing is required. Here in DC, most residences don’t use any type of raceway/metal conduit between the meter and electrical panel, and secure the SECs with a standard clamp/locknut.
However, often the SECs are behind drywall and I can’t verify it’s just using a clamp/locknut, and not a metal raceway. Should I recommend a grounding bushing be installed (given that not all the concentric knockouts are used)?
My understanding is that the grounding bushing is required only when there’s a metal raceway.