Does the NEC permit the grounded conductor to be bonded to panelboard D enclosure?

The National Electrical Code (NEC) does not permit the grounded conductor, commonly referred to as the neutral, to be bonded to the panelboard enclosure in most situations. This prohibition is based on safety concerns; bonding the grounded conductor to the panel enclosure can create parallel paths for current flow, which increases the risk of electrical shock and introduces potential fire hazards.

In a typical residential or commercial installation, the neutral must remain separate from the ground at the panelboard. This separation ensures that the grounding system provides a clear path for fault currents, while the neutral conductor carries the return current from the circuit. The main service panel is the only location where the neutral and ground are allowed to be bonded together, and this is done at the point of service entrance.

When panelboards are installed downstream from the service equipment and are not the main service disconnect, bonding the neutral to the ground in these locations is not permissible according to the NEC. Understanding this principle is crucial for ensuring safe electrical installations and compliance with the code.