Yes, it is permissible to install ground bushings and jumpers inside the panels to properly ground the panels per 517.19(D) and have a compliant design.

NEC Section 517.19(D) states:> Equipment Grounding Conductor Installed. Where an equipment grounding conductor is not installed in the raceway, the raceway shall be electrically continuous between equipment grounding termination points and shall serve as the equipment grounding conductor. Approved grounding bushings shall be used at non-metallic conduit terminations.In this case, since there is no ground wire in the conduit, you can install approved grounding bushings at the non-metallic conduit terminations and jumpers between the bushings and the panel enclosures. This will create an electrically continuous path for the equipment grounding conductor, making the raceway serve as the equipment grounding conductor.

Steps to Install Ground Bushings and Jumpers

1. Install grounding bushings at the non-metallic conduit terminations on both the 400 amp distribution panel and the elevator machine room panel.
2. Use an approved jumper to connect the grounding bushing on the 400 amp distribution panel to the grounding bar inside the panel.3. Use a second jumper to connect the grounding bushing on the elevator machine room panel to the grounding bar inside the panel.

Additional Notes: Make sure the grounding bushings and jumpers are properly sized for the application. The grounding bushings must be listed for the specific raceway system being used. The jumpers must be insulated and properly rated for the voltage and current involved. Once the grounding bushings and jumpers are installed, you should perform continuity testing to verify the grounding path. Flag for review