Automatic Changeover Switch Connection

An Automatic Transfer Switch (ATS) switches power between the main grid and a backup generator to keep the load running without interruption.

Key Components

• Main Grid → feeds the N (Normal) input of the ATS through an MCB.
• Generator → feeds the R (Backup) input of the ATS through an MCB.
• ATS / Changeover Switch → auto selects Normal or Backup and outputs to load.
• Load MCB → protects the outgoing circuit to the load.

Wiring Overview

1. Connect grid phase/neutral to ATS N (Normal) via grid MCB.
2. Connect generator phase/neutral to ATS R (Backup) via generator MCB.
3. Connect ATS Output to the Load MCB and then to the load.
4. Bond earth/ground for grid, generator, ATS, and load according to code.

How It Works

• Grid available: ATS supplies the load from Normal.
• Grid fails: ATS transfers to Backup (generator) automatically.
• Grid returns: ATS re-transfers to Normal.

Safety Notes

• Use correctly sized MCBs and follow local electrical codes (NEC/IEC).
• Prevent backfeed: never tie generator and grid lines directly.
• Test ATS operation periodically and label all feeders clearly.