Solid plaster partition walls with straw inside:fixing boxes?

[sinewove]

Came across these yesterday and wondered if anyone on here has seen them.Solid plaster with horizontal strands of straw inside.I finished up cutting the holes with a multisaw then driving 75mm screws thro the sides of the twin metal boxes,since plastic plugs were useless.Never seen these walls before and wondered how they were constructed on site.Thanks for any replies.
Regards,S

 

[stevethesparks]

Long screws to the sides, could also put some industrial strength adhesive on the box, or foam them in, keeping foam from the cable entry areas.
As much as you chop out, them walls just seem to fill up again, I hate them.

 

[SJD]

The ones I've come across, the have vertical channels at regular intervals for cabling, you just have to locate where they are, and can then site any new accessory boxes to align with the channels. I've usually just used long screws from the sides of the boxes, as you mentioned.