Gunther, I don't have it here at home but this goes back to the UL Fire Resistance Directory. (Orange Book Set)
In short, "cut in boxes" and even " some plastic boxes" are approved for rated walls up to two hour if secured to a stud. I will post the exact wording tomorrow.
Actually, all boxes used in rated walls must be supported by framing or structure.
Roger
[This message has been edited by Roger (edited 11-04-2003).]
