The neutral-ground bond (N-G bond) belongs only at the service equipment. In your description, that's likely in the trough.Here's a breakdown of why: Service Equipment

The National Electrical Code (NEC) requires that the neutral conductor be bonded to the equipment grounding conductor system only at the service equipment. This single bond provides a low-impedance path for fault current to return to the source, allowing overcurrent protective devices (fuses or circuit breakers) to operate and clear the fault.

Trough as Service Equipment

If the meter feeds directly into the trough and the trough is the first point of disconnects for the building's electrical system, then the trough is considered the service equipment. Therefore, the N-G bond must be located in the trough.

No Bonding Downstream

There should be no neutral-ground bonds in the fused disconnects or subpanels. Adding additional bonds downstream creates parallel neutral paths and can lead to circulating currents on the grounding system, which can cause a host of problems, including nuisance tripping, equipment malfunctions, and even electrical shock hazards.

How to Implement



Trough

The neutral conductor coming from the meter is bonded to the metal enclosure of the trough (or a grounding busbar within the trough) using a properly sized bonding jumper.

Disconnects

The disconnects are fed from the trough with four conductors: two hots, a neutral, and a grounding conductor. The neutral and grounding conductors are kept separate in the disconnects and subpanels. No bonding between them is allowed.

Important Considerations



AHJ Approval

Always consult with your local Authority Having Jurisdiction (AHJ) (e.g., electrical inspector) to confirm that your installation meets their specific requirements and interpretations of the NEC.

Proper Grounding and Bonding

Ensure that all equipment grounding conductors are properly sized and connected.

Service Entrance Conductors

Ensure the size and type of service entrance conductors are in compliance with NEC.

In Summary: The neutral-ground bond belongs only* in the trough, assuming that is designated as the service equipment and is the first point of disconnects after the meter. Do not create any other neutral-ground bonds in the fused disconnects or subpanels. Flag for review