Ran into this today. 2 Small clamp-like items around the main feed. They had a security system in the house, would it be to alert the company if the power was cut?
They look like current transformers – they sense when current is flowing through the wire they are wrapped around. They have all kinds of applications and security system could be one. Quick call to the security company could clear it up! No way of ‘gently’ tracing them out eh?
they are ct’s installed by the POCO for a time of use/demand metering system