Coordination of Electrical, Plumbing and Mechanical Trades
The general contractor owns the sequence even though licensed trades do the work. In Massachusetts, plumbing and gas work is performed by licensed plumbers and electrical work by licensed electricians; each trade pulls its own permit and gets its own inspections. The GC coordinates so nothing is covered or energized before it is signed off. A homeowner may generally do work on their own single-family residence, but inspection is still required.
Sequence: under-slab and underground plumbing and electrical before the slab; framing; then rough mechanical (ductwork, refrigerant lines, flues), rough plumbing (DWV and water lines, tested), rough electrical (boxes, wiring, panel); then fireblocking and firestopping of every penetration; then insulation; then rough inspections; then drywall. Blocking and chases must be planned before drywall - grab bars, panel backing, mechanical hangers.
Clearances: electrical panel working space 30 in wide by 36 in deep and clear to the ceiling; water heater and furnace clearances to combustibles per the label; flue terminations meeting the 2-ft-in-10-ft rule plus sidewall clearances; dryer and bath exhaust ducted outdoors; condensate to positive discharge.
Plumbing: DWV slope 1/4 in per ft for 2 in and smaller, 1/8 in per ft for 3 in and larger; every trap vented; vent terminals clear of windows and intakes. Electrical: AFCI and GFCI protection where the code names, smoke and carbon monoxide alarms where Massachusetts requires them, and proper bonding and grounding of metal piping.
Worked example: a 20 ft run of 2 in drain falls 20 x 0.25 = 5 in. Confirm against the plans and set blocking before the wall closes.