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How do I connect three phase power with change overswitch to db three phase show the diagram?

To connect a three-phase power system with a changeover switch to a distribution board (DB), you need to ensure that the switch can handle the three-phase configuration and that the wiring is done correctly to avoid any safety hazards or operational issues. Here’s a step-by-step guide and some key points to consider:

Wiring the Three-Phase Changeover Switch

Components Needed

A three-phase manual or automatic changeover switch (typically a four-pole switch for three phases and one neutral, if applicable).
Three-phase utility power supply (L1, L2, L3, and N if a neutral is present).
Three-phase backup power supply (e.g., from a generator).
Distribution board (DB) with appropriate connections for the three-phase load.

Connection Steps

Connect the Utility Power:
- Connect the three-phase utility power (L1, L2, L3) to the upper side of the changeover switch. If a neutral wire is present, connect it as well, but note that in many three-phase systems, especially delta-connected systems, a neutral wire may not be used1 4.
Connect the Backup Power:
- Connect the three-phase backup power (e.g., from a generator) to the lower side of the changeover switch. Ensure the backup power is also three-phase and matches the configuration (Y or Δ) of the utility power.
Connect to the Distribution Board:
- The output of the changeover switch (the side that connects to the load) should be wired to the distribution board. Ensure that the DB is configured to handle three-phase power and that the connections are made to the appropriate terminals for L1, L2, and L3.

Example Wiring Diagram

Here is a general outline based on the information from the sources:

For a Four-Pole Three-Phase Manual Changeover Switch:

Upper Side (Utility Power):
- L1 to the first terminal on the upper side
- L2 to the second terminal on the upper side
- L3 to the third terminal on the upper side
- N (if present) to the fourth terminal on the upper side
Lower Side (Backup Power):
- L1 from the generator to the first terminal on the lower side
- L2 from the generator to the second terminal on the lower side
- L3 from the generator to the third terminal on the lower side
- N (if present) from the generator to the fourth terminal on the lower side
Output to Distribution Board:
- The output terminals of the changeover switch should be connected to the corresponding terminals on the DB (L1, L2, L3, and N if applicable)2 5.

Important Considerations

Phase Sequence: Ensure that the phases are connected in the correct sequence to avoid issues with three-phase motors and other equipment4.
Current Rating: Make sure the changeover switch and all connections are rated for the current and voltage of the system.
Indication and Safety: Use indication lamps or voltmeters to monitor which phase is active and to ensure safety during switching operations5.

Here is a simplified diagram based on these steps:

Utility Power (L1, L2, L3, N)  ------>  Changeover Switch (Upper Side)
                                             |
                                             |
Backup Power (L1, L2, L3, N)  ------>  Changeover Switch (Lower Side)
                                             |
                                             |
                                             v
Changeover Switch Output (L1, L2, L3, N) ------> Distribution Board

For a detailed wiring diagram, you can refer to specific tutorials or manuals that match your exact setup, such as those provided in the sources2 5.