ATS Failure Automatic Transfer Switch failures

ATS Failure – automatic transfer switch (ATS) failures can happen

 Automatic transfer switch (ATS) is a device that automatically transfers the electrical power supply from its primary source supply to a backup source, ‘standby power generator’, when the ATS senses a failure or outage in the primary supply source,( which is usually the national GRID supply).

An ATS consists of copper bars and contactors, which keep the primary power source separated from the standby power source in an isolated manner.

The ATS constantly monitors the supply for harmonic distortion which it ‘sees’ as being a prelude to a power loss.

Should the ATS ‘see’ the primary power source operating outside of safe operational parameters then the ATS will automatically isolate the primary power source and switch over to the backup power source as well as sending a start signal to the backup generator to start up and provide power.

This action will happen, without human intervention, either prior to the power loss event of within seconds of sensing the power loss.
Service and Maintenance contracts must be active and actioned.

ATS operate like this in the real world.

1.The Electrical power to your building is usually supplied from the primary power source, which is the National GRID supply.

2.The ATS is constantly monitoring the quality of the primary power source since it was installed by Power Continuity Systems.

3. When a failure occurs in a primary power system, the ATS will automatically isolate the primary power source and switch over to the backup power source, within seconds.

4. The ATS sends a start signal to the backup generator

5. Your backup generator starts to take the building load with 20-30 seconds, completely independent of the failed GRID supply.

What can cause ATS failure?

ATS Failure – automatic transfer switch (ATS) failures


If you can hear ‘chattering’ this is a sign that debris is bouncing around between the contactors in your ATS. Your ATS will still operate BUT….. it is an indication that parts are wearing and in need of replacement during the coming 12 months.


If you can smell ‘burning’ emanating from the ATS then this is a sign that the terminals or some of the terminals have burned out.
Fire is a real possibility. Business Continuity needs to be addressed.
REPLACE immediately as your ATS won’t operate without replacement.
Service and Maintenance is important.


Loose Metal debris inside the ATS will cause a ‘Buzzing’ sound.

Get your local generator engineer to isolate the ATS and clean out all metal debris . Clean and then safely re-energise the ATS

4.Control panel dead

Without a visual operating control panel your ATS will NOT operate.

If the control panel has NO life and NO images then as a matter of urgency replace with a NEW power control panel.

ATS Failure Control panels can fail due to age or component failure

For more assistance please contact Power Continuity Engineers on

 0845 055 8455 We’re here to help 24/7 in the UK

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