What the 1700 A AC-1 rating means for your BOM line
The LC1F1700N7 is a 3-pole contactor from the TeSys F range, rated 1700 A conventional free-air thermal current (Ith) and 1700 A operational current in AC-1 utilisation category — that is, purely resistive loads like large heating banks, furnace elements, or power-factor correction capacitor banks. The AC-1 rating is the headline figure here; this contactor is not characterised for motor starting (AC-3) or mixed loads. The control circuit is 415 VAC at 40-400 Hz, with a pickup range of 0.85 to 1.1 Uc and a dropout band of 0.3 to 0.5 Uc — so on a 400 V nominal supply, the coil holds in above 340 V and drops out reliably below 208 V.
Physical integration — plate-mount, bar connections, torque specs
Mounting is plate-mount only — no DIN-rail option on this frame size. The dimensions are substantial: 438 mm wide, 332 mm high, 238.6 mm deep. Power-circuit connections are via bolted bars accepting up to three cables per pole with a busbar cross-section of 100 x 5 mm. Tightening torque on the power circuit is 58 N.m — that is a high-torque joint requiring a torque wrench, not a screwdriver. Control-circuit connections use screw-clamp terminals accepting 1 to 4 mm² flexible or solid wire, torqued to 1.2 N.m. The 36 W heat dissipation (200 W per pole in AC-1 duty) means the panel must account for thermal rise; forced ventilation or generous enclosure sizing is advisable at full rated current.
Fault handling and coordination
The LC1F1700N7 is rated for a short-time withstand current (Icw) of 10,000 A for 10 seconds at 40 °C, stepping down to 3,000 A for 10 minutes — this defines the maximum fault current the contactor can carry without welding its main poles while a backup overcurrent device clears. The associated fuse recommendation is 1600 A gG at ≤ 440 V. Rated breaking capacity is 2550 A per IEC 60947-4-1. Rated impulse withstand voltage is 8 kV, overvoltage category III, which suits fixed-installation distribution panels.
The contactor is certified to IEC 60947-4-1, IEC 60947-1, EN 60947-4-1, EN 60947-1, JIS C8201-4-1, UL 60947-4-1, and CSA C22.2 No 60947-4-1. Rated insulation voltage is 1000 V per IEC/UL 60947-4-1, and 1500 V per VDE 0110 group C. Protective treatment is TH (tropicalised) for humid environments. Storage temperature range is -60 to 80 °C; operating ambient is -5 to 40 °C.