Visonic Trouble — AC Mains Power Failure

What Does This Error Mean?

An AC Trouble warning on your Visonic alarm means the panel is no longer receiving power from the mains electricity supply. It has switched to battery backup, which will only last 8–24 hours depending on the battery age and how active the system is.

Affected Models

Visonic PowerMax Pro
Visonic PowerMax Complete
Visonic PowerMax Express
Visonic PowerG Hub

Common Causes

Power cut in your building or street
Tripped circuit breaker on the alarm's dedicated circuit
Blown fuse in the alarm panel's transformer
Damaged or disconnected wiring between the transformer and panel
Failed transformer/power supply unit inside or near the panel

How to Fix It

Check your general power supply

Is the rest of your home powered normally? If you have a wider power cut, the alarm will automatically restore once the electricity returns.
Check the circuit breaker

Find your fuse board/consumer unit. Look for a breaker labelled 'Alarm' or 'Security' that may have tripped. If tripped, reset it.
Listen for beeping

Visonic panels typically beep every 30–60 seconds during an AC trouble condition. You can silence this temporarily by entering your user code and pressing 'Off' or 'Disarm'.
Monitor battery level

The panel will continue to function on battery. If the power outage lasts more than a few hours, check the panel display for a low battery warning.
If power is restored and trouble persists, call a technician

Continued AC trouble after mains power is restored means the alarm's internal transformer or wiring has failed. A security technician should inspect it.

When to Call a Professional

Only if the power has been restored to your home but the AC trouble warning persists — this indicates a fault in the alarm's own power supply.

Visonic AC Mains Power Failure

When your Visonic alarm displays an AC Trouble warning (sometimes shown as “AC Fail” or a flashing mains power indicator), it means the panel’s connection to your home’s electricity has been lost.

Visonic panels have a built-in rechargeable backup battery for exactly this situation. Your home remains protected — but only for as long as the battery holds charge.

What to Do First

Check whether your home has power at all (lights, sockets)
If there is a wider outage — wait for it to be resolved
If only the alarm has lost power — check the circuit breaker and call your alarm company

Silencing the Beeping

While the trouble condition is active, the panel will periodically beep to alert you. Enter your user PIN + Off/Disarm to acknowledge and silence the warning. The underlying fault remains until the power issue is resolved.

Frequently Asked Questions

Will my alarm still go off if there is a break-in during an AC power failure?

Yes — the panel runs on its backup battery and remains fully armed. Sirens and notifications will still activate during an intrusion, as long as the battery has charge.

How long will the Visonic battery last during a power cut?

A healthy battery provides 8–24 hours of standby. If your battery is more than 3–4 years old, it may not last as long. A persistent low-battery warning after power is restored means the battery needs replacement.