These joists are used widely in our area. You can pretty much drill any where on the web of these joists, provided that your hole isn't larger than 1" You are permitted to make larger holes, but you must stay away from either end of the joist. Most lumber yards/suppliers will provide you with a schedule of how far you have to be from the ends of the joist to make a larger diameter hole. Naturally, the wider the joist, the better support it provides, and the closer you can drill at either end of the joist. Also as pointed out earlier, some manufacturers have premade 'knockouts' running at 2-4' intervals along the span of the joist. Just take a hammer and punch them out. A really ingenious idea and saves much drilling. As far as mounting of the boxes and stapling, we use the lower part of the 2x3 for this, just as you would on a normal wood joist.
Cheers!
[This message has been edited by Sandro (edited 01-30-2002).]
