Okay, let's break this down and clarify the grounding and bonding requirements for your detached shed with a 60A subpanel. You're right to question the AHJ and ensure compliance with the NEC (National Electrical Code).

Understanding 250.32(B): Detached Buildings or Structures Supplied by a Feeder or Branch Circuit

This section addresses the grounding and bonding requirements for detached buildings supplied by a feeder (like your 60A circuit). Here's the relevant part to your situation: 250.32(B)(1) Grounded Systems

This applies if the feeder circuit is grounded (which it almost certainly is in a typical residential service). It states that the grounding electrode system (GES) at the detached building must be connected to the following: The grounding electrode conductor (GEC) at the detached building. The equipment grounding conductors (EGCs) that run with the feeder to the detached building. The grounded conductor (neutral) of the feeder if you are allowed to use the feeder neutral for grounding at the shed.

What you've done so far Installed two ground rods, 8 feet apart: This is good. You've established a local grounding electrode system (GES). Installed a 60A disconnect outside the shed. Installed a 60A subpanel inside the shed.

The Key Question: Neutral-Ground Bond

The most critical point to determine is where you are allowed to bond the neutral to ground. If you are using a four-wire feeder (hot, hot, neutral, ground), the neutral and ground should ONLY be bonded at the service entrance (main panel) at the house and NOT at the detached building. This keeps neutral current from flowing on the equipment grounding conductors.However, there are exceptions where the neutral can be bonded in the shed, which I will cover.

How to Properly Ground and Bond Your Shed

Here's the recommended approach, and I'll address the common scenarios: Scenario 1: Four-Wire Feeder (Hot, Hot, Neutral, Ground) – Most Common and Preferred1. Feeder

Run a 4-wire feeder (two hots, a neutral, and an equipment grounding conductor) from the main panel in your house to the disconnect at the shed. The EGC must be sized per NEC Table 250.122, based on the rating of the overcurrent device protecting the feeder (your 60A breaker in the main panel). Typically, this will be a #6 copper or #4 aluminum.
2.

Disconnect

Land the feeder conductors (two hots, neutral, and ground) in the disconnect. The equipment grounding conductor (EGC) should be bonded to the metal enclosure of the disconnect (if metal).

Do NOT bond the neutral to the enclosure or ground at the disconnect.3. Subpanel

Run the same 4 wires from the disconnect into the subpanel in the shed.4.

Subpanel Bonding

Land the two hots and the neutral on the appropriate lugs/terminals. Land the equipment grounding conductor (EGC) on the grounding bar in the subpanel.

Do NOT bond the neutral to the grounding bar in the subpanel. Remove the bonding screw or strap if the subpanel comes pre-bonded. This is crucial.5. Grounding Electrode Conductor (GEC)

Connect a grounding electrode conductor (GEC) from the grounding bar in the subpanel to your ground rods. The GEC size is based on NEC Table 250.66, based on the size of the feeder conductors. For a 60A feeder, the GEC will generally be #8 copper (check the table to be sure, as the size of your feeder conductors matters).
6.

Important

Ensure the equipment grounding conductor (the wire running with the feeder) is properly connected and sized. This provides the fault current path back to the main panel.

Scenario 2: Three-Wire Feeder (Hot, Hot, Neutral) – Allowed Under Specific Circumstances (250.32(B)(1) Exception 1) Conditions

This is only permitted if there are no continuous metallic paths between the house and the shed (e.g., no underground metallic water pipes, no shared metallic conduit containing other circuits).

Neutral as Ground

In this case, the neutral can be used as the equipment grounding conductor, but only if these conditions are met: The neutral conductor is insulated. The neutral conductor is not smaller than the required grounding electrode conductor specified in Table 250.66

Wiring

1. Run a 3-wire feeder (two hots, a neutral) from the main panel in your house to the disconnect at the shed.
2.

Disconnect

Land the feeder conductors (two hots and neutral) in the disconnect.3.

Subpanel

Run the same 3 wires from the disconnect into the subpanel in the shed.4.

Subpanel Bonding

Land the two hots and the neutral on the appropriate lugs/terminals.

Bond the neutral to the subpanel enclosure. This creates a neutral-ground bond at the shed.5. Grounding Electrode Conductor (GEC)

Connect a grounding electrode conductor (GEC) from the neutral bar in the subpanel to your ground rods.

Caution

This method is generally discouraged due to safety concerns.

Scenario 3: Three-Wire Feeder (Hot, Hot, Grounded Conductor) – Rarely Encountered (and Usually Incorrect) I am including this for informational purposes only. This is similar to scenario 2, with the exception that there is no neutral provided. It is important to note that the grounded conductor in this scenario MUST be bonded to the subpanel enclosure AND a grounding electrode system. It also must be sized per the larger of 250.122 and 250.
166. This configuration is not suitable for powering 120V loads.

Addressing Your AHJ's Potential Misunderstanding

Your AHJ's insistence on running the GEC to both the disconnect and the subpanel is technically incorrect in most cases. The GEC runs from the grounding bar in the subpanel to the ground rods. The disconnect is bonded to the subpanel through the EGC in the feeder.

Recommendations1. Use a Four-Wire Feeder

This is the safest and most compliant approach, especially for modern installations.2.

Confirm with Your AHJ

Before proceeding, politely ask the AHJ to clarify their reasoning and cite the specific NEC code section they are interpreting that requires the GEC to go to both the disconnect and the subpanel (when using a four-wire feeder). It's possible they have a local amendment, but it's important to understand their justification.3.

Provide Documentation

Be prepared to show them the NEC code sections (250.32(B), 250.66, 250.122) and diagrams illustrating the proper grounding and bonding of a detached building with a four-wire feeder. Mike Holt Enterprises and other electrical training resources have excellent illustrations.
4.

Document Everything

Keep a record of all communications with the AHJ, including dates, names, and the substance of the conversations. This can be helpful if there are disputes later.

In Summary Ground rods are good. Use a four-wire feeder if possible. Bond only at the main panel (and maybe at the shed subpanel if using a 3-wire feeder and meeting the strict exception requirements). GEC goes from the subpanel grounding bar to the ground rods. Don't let neutral current flow on the equipment grounding conductors.By following these guidelines and communicating clearly with your AHJ, you can ensure a safe and code-compliant installation. Good luck! Flag for review