A 5G mast was set on fire at Doagh Road in Newtownabbey on Tuesday evening (11 November).
It was reported to police shortly after 7pm.
Officers attended the scene, along with the Northern Ireland Fire and Rescue Service, who extinguished the fire.
Part of the Shore Road and Doagh Road were closed for a time while emergency services attended, however they have since been reopened.
Detective Sergeant Ash said: “This is just one of a number of 5G masts that have been set on fire recently and I cannot emphasise enough the dangers of lighting fire to electrical equipment. This is extremely reckless, and those responsible are putting themselves and members of the public at serious risk.
“We are treating this as arson and I am appealing to anyone who may have witnessed anyone suspicious in the area or anyone with CCTV or other footage that could assist with enquiries, to contact detectives on 101 quoting reference 1333 11/11/25.”
Alternatively, a report can be submitted online using our non-emergency reporting form via http://www.psni.police.uk/makeareport/. You can also contact Crimestoppers anonymously on 0800 555 111 or online at http://crimestoppers-uk.org/.