Okay, let's break down the requirements for using EMT as an Equipment Grounding Conductor (EGC) for a 225A panel, focusing on fitting types and code compliance.

Key Considerations and Code References (Primarily based on the NEC)



Suitability of EMT as an EGC

EMT is permitted to be used as an EGC.

250.118(4) Metal Raceways

Electrical metallic tubing (EMT) shall be permitted for use as an equipment grounding conductor.

250.136(A) Connection to an Equipment Grounding Conductor. Noncurrent-carrying conductive metal parts of equipment, raceways, and other enclosures, where required to be connected to an equipment grounding conductor, shall be connected in accordance with 250.8 using equipment grounding conductors, jumpers, and listed fittings. 250.8(A)(5) Connection of Grounding and Bonding Equipment Listed for the purpose. Mechanical Integrity and Electrical Continuity are Paramount

The entire EMT system must be mechanically secure and provide a continuous, low-impedance electrical path back to the source (service equipment or separately derived system). This is crucial for effectively clearing ground faults.

Fittings Matter

The type of fittings you use directly impacts the electrical continuity and suitability of the EMT as an EGC.

250.96 Bonding Other Enclosures (A) General. Metal raceways, cable trays, cablebus, cable armor, cable sheath, enclosures, frames, fittings, and other metal non–current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary. Fault Current Capacity The EMT must be sized and installed in a manner that it can safely handle the available fault current.

Set-Screw vs. Compression Fittings



Set-Screw Fittings

Set-screw fittings are generally permitted for EMT used as an EGC,

BUT they must be listed for grounding and suitable for the application. In high fault current applications, there can be concern about the set screws maintaining sufficient contact under fault conditions. They must be properly torqued (according to the manufacturer's instructions and/or listing requirements). Loose set screws are a common cause of poor grounding. Compression Fittings

Compression fittings are generally preferred for EMT used as an EGC, especially in applications where high fault currents are possible, because they typically provide a more robust and reliable connection with lower impedance. Compression fittings are less prone to loosening over time.

Specifically for a 225A Panel

Given the 225A panel, which implies a potentially substantial fault current:1.

Best Practice Recommendation



Compression fittings are the better choice. They offer superior electrical contact and mechanical strength, enhancing the effectiveness of the EMT as an EGC. This is especially true when you've relocated and rerouted the conduit, ensuring optimal performance.2. If using Set-Screw Fittings (proceed with caution)



Verify Listing

Absolutely confirm that the set-screw fittings you're using are specifically listed for grounding applications (look for markings indicating this).

Proper Installation

Torque set screws to the manufacturer's specifications using a calibrated torque wrench. Overtightening or undertightening can both compromise the connection.

Inspection

Regularly inspect set-screw fittings for looseness, especially after the initial installation.3.

Consider a Supplemental EGC

You can use a supplemental EGC (a separate grounding conductor run inside the EMT) to supplement the EMT's grounding capabilities. This provides an extra measure of safety and redundancy. This is generally a great idea for higher ampacity services and panels. Size this supplemental EGC according to NEC Table 250.122.
4.

Bonding Jumpers

Ensure that any boxes or enclosures within the EMT run are properly bonded using bonding jumpers to maintain electrical continuity.5.

Inspect and Test

After installation, it is important to visually inspect all connections to ensure they are properly made and tight. Additionally, it is highly recommended to perform an impedance test of the grounding system to verify its effectiveness.

Important Considerations for your Relocation/Rerouting



Conduit Condition

Inspect the EMT itself for any damage (dents, corrosion). Damaged EMT may compromise its grounding capabilities.

Number of Bends

Minimize the number of bends in the EMT run. Excessive bends can increase impedance and reduce fault current capacity.

Proper Support

Secure the EMT with appropriate straps and supports to prevent movement and stress on the fittings.

Make sure to remove any paint or coating from the EMT that can interfere with a proper connection.In Summary

While set-screw fittings can be used if they are listed for grounding and properly installed, compression fittings are generally the better choice for a 225A panel due to their superior electrical contact and mechanical strength. Given that you've relocated the panel and rerouted the conduit, using compression fittings provides an extra margin of safety and reliability. Consider a supplemental EGC for enhanced grounding performance. Always prioritize proper installation techniques and adherence to the NEC.

Disclaimer: I am an AI chatbot and cannot provide definitive electrical code interpretations. Consult with a licensed and qualified electrical contractor or electrical inspector for specific advice tailored to your installation and local codes. They can assess the specific conditions and requirements of your project. Flag for review