a false alarm

false alarm

A benign situation initially mistaken for an emergency. Mary thought she was going into labor, but it turned out to be a false alarm. When the smoke detectors started beeping, we thought the building was on fire, but it was just a false alarm caused by faulty wiring.
See also: alarm, false
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

a false aˈlarm

a warning of something, especially something unpleasant or dangerous, which does not in fact happen: They thought the packet contained a bomb but it was a false alarm.
See also: alarm, false
Farlex Partner Idioms Dictionary © Farlex 2017
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References in periodicals archive ?
Reducing false alarms with Smart Signal can help save taxpayer dollars and prevent property owners from incurring costly fees or fines due to a false alarm response.'
However, it turned out to be a false alarm and fire crews were not asked to attend.
If approved as expected, the ordinance would also update references to the correct National Fire Prevention Association's standards and define for the first time what a false alarm management company is for administrative processes related to permitting, registration, billing and data processing.
JERUSALEM: Rocket warning sirens went off on Thursday on the Israeli-occupied Golan Heights, but the Israeli military quickly said it was a false alarm.
However, it was established that it was a false alarm and residents were allowed back in their homes.
31 (ANI): The head of Hawaii's emergency management agency has resigned and a state employee who sent out a false alarm of an incoming ballistic missile has been fired, officials said on Tuesday, after the mistake caused statewide panic earlier this month.
Many Hawaiians first learned that the alert was a false alarm from Hawaii Congresswoman Tulsi Gabbard.
It was confirmed to be a false alarm caused by human error less than an hour later, but that did not stop Hawaiians from preparing for the worst.
Washington, Rabi'II 26, 1439, January 13, 2018, SPA -- An alert saying a missile was headed for Hawaii was a false alarm, officials said Saturday after people in the US state were alarmed to see a warning about an imminent threat on their mobile devices, according to dpa.
Rescuers' search over 'false alarm' A FALSE alarm sparked a major sea and air search off Anglesey.
In total 158 of those were due to Automatic Fire Alarms wrongly alerting crews A spokesman for the Northern Ireland Fire and Rescue Service said: "In cases where human error or system failure may result in the actuation of a false alarm, firefighters are alerted and attend due to the nature of the call.
Merseyside Fire & Rescue Service was called to Lawrence Road at 6.48am yesterday but said the call-out was a false alarm.
This resulted in fire engines being mobilised on blue lights 18,000 times - almost ten a day - to what turned out to be a false alarm.