Am these be used outdoors with low voltage lights?

If one uses liquid electric tape. apply all over each connector. I've used liquid electric tape over all my inground landscape connections no issues

no I would not use these connectors for that application as they are not waterproof. Look for the weatherproof connectors sold in the stores they have a gel inside them that helps seal the connection. have fun Ron at ron.kipper@idealindustries.com