The 6 pound limit you refer to is for 'old work' boxes, where the box is supported by the drywall, rather than by being attached to a framing member.
Shuruuda shantaa oo jihaadka ood sheegtey oo shantaa waa "shuruudu sixatil camal" cibaadaatka kalena way la wadaagaane jihaadka kaliya kuma koobna.