How does an automatic transfer switch work?

An automatic transfer switch (ATS) is a critical safety device that automatically switches your home's electrical supply from the utility grid to your backup generator when the power goes out, then switches back when utility power is restored. This happens without any manual intervention, ensuring seamless backup power for your home.

The ATS continuously monitors the voltage and frequency of your incoming utility power from NB Power. When it detects a power outage, voltage drop, or frequency issue, it sends a start signal to your backup generator. Once the generator reaches proper voltage and frequency (typically within 10-30 seconds), the transfer switch safely disconnects your home from the utility grid and connects it to the generator. This prevents dangerous "backfeeding" that could electrocute NB Power workers trying to restore service.

How the switching process works: The ATS contains heavy-duty contactors (electrical switches) that physically move to break the connection with one power source before making connection with the other. There's a brief interruption (usually 5-10 seconds) during the transfer to ensure the two power sources never connect simultaneously. Modern units include time delays to prevent nuisance switching from brief power blips.

Key safety features include neutral switching (required by TSANB), which ensures both the hot and neutral conductors are properly transferred. The switch also monitors generator performance - if the generator fails or overheats, it will attempt to transfer back to utility power if available. Most units include manual override capabilities for testing and maintenance.

In New Brunswick, TSANB permits and inspections are required for ATS installation. The Canadian Electrical Code specifies installation requirements including proper grounding, disconnect locations, and clearances. Your licensed electrician will coordinate with TSANB for permits and ensure the installation meets all code requirements.

Generator sizing is crucial - the ATS must match your generator's capacity and your home's electrical load. A typical New Brunswick home might need a 20kW generator with a 200-amp transfer switch to handle essential circuits during ice storms. Some homeowners opt for smaller units (10-14kW) with load management to prioritize critical circuits.

Installation typically costs $5,000-$15,000 depending on generator size and electrical complexity. Given New Brunswick's frequent ice storms and power outages, an ATS with backup generator is an excellent investment for maintaining comfort and preventing frozen pipes during extended outages.

Need help finding an electrician experienced with generator and transfer switch installation? New Brunswick Electrical can match you with qualified professionals for a free estimate on your backup power project.