This bushing current transformer is the 1 A secondary version of the 100 A CT for 3NJ6 switch disconnectors. If the panel meter or energy monitor is located far from the switchgear, the 1 A output keeps measurement errors small where a 5 A secondary would already suffer from line losses on the connecting cables.

Why 1 A Secondary?

• Line loss is proportional to current squared: P_L = I²R. At 1 A, the loss on the same wiring is just 4 % of the 5 A case — critical for cable runs of 20 m or more from the CT to the instrument.
• Same 1.5 VA burden: the transformer still drives a standard 1 A instrument input, but with lower current and therefore less voltage drop on the connecting wires.
• Ideal for retrofits where existing cabling is thin or where the meter is located in a distant control room.

Key Specifications

• 100/1 A ratio: a 100 A primary current produces 1 A on the secondary — check that your meter supports 1 A input.
• Class 1 accuracy, 1.5 VA burden: sufficient for panel ammeters and energy monitors in industrial distribution.
• FS 5 overcurrent limiting factor: the core saturates at 500 A, protecting the connected instrument from short‑circuit damage.
• 21 mm cable opening: accepts feeder conductors up to approximately 25 mm².
• Tool‑free mounting: clips directly onto the 3NJ6 frame.

Technical Specifications