Here are the general steps for installing an MCCB (Molded Case Circuit Breaker) as a replacement for the main disconnect link switch in a Carrier 30XA chiller:

1. *Pre-installation checks*:
- Ensure the chiller is shut down and locked out/tagged out.
- Verify the electrical supply is disconnected.
- Check the MCCB's ratings match the chiller's requirements.
2. *Disconnect electrical connections*:
- Carefully disconnect wires from the old switch.
- Label wires for easy identification.
3. *Remove old switch*:
- Take out the old switch from the panel or enclosure.
4. *Install new MCCB*:
- Mount the MCCB in the panel or enclosure.
- Ensure proper alignment and secure fastening.
5. *Connect electrical wires*:
- Connect labeled wires to the appropriate MCCB terminals.
6. *Tighten connections*:
- Ensure all connections are secure and meet torque specifications.
7. *Perform safety checks*:
- Verify the installation meets safety standards.
- Check for proper clearance and insulation.
8. *Test the MCCB*:
- Perform a functional test to ensure proper operation.
9. *Start-up and commissioning*:
- Follow the chiller's start-up procedure.
- Monitor the system for proper operation and performance.

Remember to consult the Carrier 30XA chiller manual, MCCB manufacturer instructions, and relevant electrical safety standards (e.g., NFPA 70, NEC) for specific guidance and requirements. Additionally, consider consulting a qualified electrician or technician if you're unsure about any aspect of the installation.