I was impressed at @ remodel job today. The sheetrock was cut perfectly around the boxes, a matchbook cover would not make it's way bettween rock & box, this without any mud... The owner( DIY'er) had applied his wife'slipstick to the boxes, pressed the rock against them, and cut as marked, resulting in better than the pro's do.
314.21 Repairing Plaster and Drywall or Plasterboard. Plaster, drywall, or plasterboard surfaces that are broken or incomplete shall be repaired so there will be no gaps or open spaces greater than 3mm (1/8 in.) at the edges of the box or fitting. 300.21 Spread of Fire or Products of Combustion. ......Openings around electrical penetrations through fire-resistant-rated walls, partitions, floors, or ceilings shall be firestopped using approved methods to maintain the fire resistance rating.