Square D 5NR-401 Current Transformer 400:5 CT Ratio

Square D 5NR401 Current Transformer delivers a 400:5 CT ratio with a 400 A primary and a 5 A secondary, designed for metering and protection in 600 V class electrical systems. Rated for 50–400 Hz operation, it carries UL and CUL listings and a 600 V maximum voltage, with a burden rating of 12.5 VA at 60 Hz (25 VA at 400 Hz). The device has a DC resistance of 0.0883 ohm at 25°C and weighs about 1 lb, featuring a 1.56 in (1-9/16 in) inner-diameter window for conductor passage and including a mounting bracket for secure installation. It provides ±1% accuracy at its rated current and is typically used to feed meters, relays, and solid-state transducers in electrical panels and switchgear.