Holes in 2x12 for wiring question?

[Mak]

Ive got dimensional 2x12 joists spanning 17 feet for my floor. Each joist allready has about 4 to five half inch hole cut in them for wiring to pass through, both in the middle and near the ends. I want to wire my basement now, can I continue to drill more holes for wiring? As my floor allready has a fair amount of deflection I hate to drill more holes in the joists? How many holes can I have and where should they be, middle or ends, up low or high? Can I staple the wires to the bottom of the joists?

[Sweep]

It's all specified in your building code but in general try to stay out of the middle third of the span, stay at least 2" away from the top or bottom, keep holes at least 2" apart, the middle is better than the top or bottom of the joist. Hole sizes are limited to 3 3/4" for a 2x12.

[Sparks]

If you're really concerned you could staple the romex to running boards attached to the bottom of the joists. This would be code compliant. Just be cautious about protecting the romex at a lower height if it isn't between studs. Some areas allow surface running romex and some do not. ( I'm speaking of at heights where it would be subject to physical damage.)