EMT (Electrical Metallic Tubing): thin-wall steel conduit, unthreaded. ANSI C80.3, UL 797. 3/4 in trade size = 0.922 in OD, 0.824 in ID. Max conductor fill: 40% area (NEC 344.22). Typical fill: 3-4 #12 THHN conductors. Fittings: set-screw or compression connectors and couplings. Bending: max 360° total bends between pull points. Support spacing: 10 ft max, within 3 ft of boxes. Not permitted: wet locations exposed to physical damage, underground, corrosive environments. Use IMC or RMC for those. Cost: $0.50-$1.50/ft. Weight: 0.45 lb/ft. EMT is NOT a grounding conductor by itself in all jurisdictions — check local amendments. CSI 26 05 33. Cutting: rotary cutter (no hacksaw to avoid burrs). Reaming required after cutting.