hole too big - expanding foam strong enough?

[cozd]

my builder has put some plasterboard up which i'll be attaching pendant lights (not very heavy). but he 'kindly' punched two holes for the cables - which, unfortunately, are way too big for me to attach the pendant lamps i've already got.

i've heard about an expanding foam which you can drill into for lightweight fixings - anyone know about it please?

ta

[welsh brickie]

you would be better using drywall adhesive ,with foam you cant get a fixing.