SENTRON 3NJ6

The SENTRON 3NJ6 series covers pluggable bushing current transformers from 150 A to 600 A, designed for direct-fit installation on Siemens 3NJ6 in-line switch disconnectors with fuses. Both 1 A and 5 A secondary outputs are available across the range. Class 0.5 models provide legal-for-trade grade accuracy for precision metering and energy audits, while Class 1 models deliver cost-effective performance for routine load monitoring. All units share a 21 mm bushing opening and snap into the dedicated accessory port without tools or additional wiring. A CT busbar for mounting up to three transformers completes the ecosystem.

Products in This Series

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Product	Key Specifications	Action
3NJ6920-3DG00 Siemens 3NJ6920-3DG00 CT Busbar, 4 Transformer Positions, NH0 PDF	A CT busbar assembly for mounting 4 bushing current transformers onto SENTRON 3NJ6 (NH00) in-line switch disconnectors with fuses. 14 mm bushing openings. Rated up to 690 V AC / 440 V DC per IEC EN 60947-3. Modular plug-in design — retrofittable at any time without disconnecting the main circuit. Net weight: 0.248 kg.	View Product
3NJ6940-3BJ23 Siemens 3NJ6940-3BJ23 400/5A Bushing CT, Class 0.5 with Legal PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 400/5 A with Class 0.5 accuracy and legal-for-trade calibration — the certified 400 A choice for billing applications. Same tool-free plug-in installation and 32 mm cable window. For precision metering without calibration, see the 3BJ22.	View Product
3NJ6920-3DD00 Siemens 3NJ6920-3DD00 CT Busbar, 4 Transformer Positions, NH0 PDF	A CT busbar assembly for mounting 4 bushing current transformers onto SENTRON 3NJ6 (NH00) in-line switch disconnectors with fuses. Standard bushing. Rated up to 690 V AC / 440 V DC per IEC EN 60947-3. Modular plug-in design — retrofittable at any time without disconnecting the main circuit. Net weight: 0.259 kg.	View Product
3NJ6920-3DB00 Siemens 3NJ6920-3DB00 CT Busbar, 1 Transformer Position, NH00 PDF	A CT busbar assembly for mounting 1 bushing current transformer onto SENTRON 3NJ6 (NH00) in-line switch disconnectors with fuses. Standard bushing. Rated up to 690 V AC / 440 V DC per IEC EN 60947-3. Modular plug-in design — retrofittable at any time without disconnecting the main circuit. Net weight: 0.066 kg.	View Product
3NJ6940-3BK11 Siemens 3NJ6940-3BK11 500/1A Bushing CT, Class 1 for Economic PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 500/1 A with Class 1 accuracy — the most economical way to monitor a 500 A feeder with a remote meter. The 1 A secondary handles long cable runs with minimal losses. Fits cables up to 32 mm.	View Product
3NJ6940-3BH13 Siemens 3NJ6940-3BH13 300/1A Class 0.5 Legal-for-Trade Bushin PDF	300/1 A current transformer with Class 0.5 accuracy and legal-for-trade calibration — the billing-grade option in the SENTRON 3NJ6940 CT family. The 1 A secondary eliminates I²R losses over long CT-to-meter cable runs, while factory calibration and conformity assessment make it ready for revenue metering. Expect longer lead times (~30 days) due to the calibration process.	View Product
3NJ6940-3BH21 Siemens 3NJ6940-3BH21 300/5A Class 1 Bushing Current Transfor PDF	300/5 A pluggable current transformer for SENTRON 3NJ6 in-line fuse-switch-disconnectors. The 5 A secondary connects directly to standard panel ammeters and energy meters — the practical choice when the CT is near the instrument. Class 1 accuracy (±1%) is sufficient for load monitoring, overload detection, and non-billing energy tracking in low-voltage distribution panels.	View Product
3NJ6930-3BG21 Siemens 3NJ6930-3BG21 SENTRON NH1 Bushing Current Transformer PDF	A pluggable NH1 bushing current transformer for SENTRON 3NJ62/63 in-line switch disconnectors with fuses. 250/5 A ratio, Class 1 accuracy, 2.5 VA rated burden. Accepts cables up to 21 mm diameter. Compact 44×65×30 mm form factor. Weight: 184 g.	View Product
3NJ6940-3BK12 Siemens 3NJ6940-3BK12 500/1A Bushing CT, Class 0.5 Accuracy f PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 500/1 A with Class 0.5 accuracy — precision sub-metering for 500 A feeders where the meter is located away from the switchboard. The 1 A secondary minimises voltage drop over long cable runs. Fits cables up to 32 mm.	View Product
3NJ6940-3BJ13 Siemens 3NJ6940-3BJ13 400/1A Bushing CT, Class 0.5 with Legal PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 400/1 A with Class 0.5 accuracy and legal-for-trade calibration — billing-grade measurement for 400 A feeders where the meter is installed remotely. The 1 A secondary preserves calibrated accuracy over long cable runs.	View Product
3NJ6930-3BG11 Siemens 3NJ6930-3BG11 SENTRON NH1 Bushing Current Transformer PDF	A pluggable NH1 bushing current transformer for SENTRON 3NJ62/63 in-line switch disconnectors with fuses. 250/1 A ratio, Class 1 accuracy, 5 VA rated burden. Accepts cables up to 21 mm diameter. Compact 44×65×30 mm form factor. Weight: 190 g.	View Product
3NJ6930-3DB00 Siemens 3NJ6930-3DB00 CT Busbar, 1 Transformer Position, NH1 PDF	A CT busbar assembly for mounting 1 bushing current transformer onto SENTRON 3NJ6 (NH1) in-line switch disconnectors with fuses. For higher-current NH1 frame disconnectors. Rated up to 690 V AC / 440 V DC per IEC EN 60947-3. Modular plug-in design — retrofittable at any time without disconnecting the main circuit.	View Product
3NJ6920-3DC00 Siemens 3NJ6920-3DC00 CT Busbar, 3 Transformer Positions, NH0 PDF	A CT busbar assembly for mounting 3 bushing current transformers onto SENTRON 3NJ6 (NH00) in-line switch disconnectors with fuses. Standard bushing. Rated up to 690 V AC / 440 V DC per IEC EN 60947-3. Modular plug-in design — retrofittable at any time without disconnecting the main circuit. Net weight: 0.189 kg.	View Product
3NJ6930-3BG23 Siemens 3NJ6930-3BG23 250/5A Class 0.5 Legal-for-Trade Bushin PDF	250/5 A bushing current transformer for SENTRON 3NJ62/63 NH1 in-line fuse-switch-disconnectors. Class 0.5 accuracy with legal-for-trade calibration enables billing-grade energy measurement in compact low-voltage panels. The 14 mm cable entry fits standard NH1 feeder cables — note the 48 mm depth requires clearance behind the disconnector.	View Product
3NJ6940-3BJ22 Siemens 3NJ6940-3BJ22 400/5A Bushing CT, Class 0.5 Accuracy f PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 400/5 A with Class 0.5 accuracy — the precision choice for 400 A feeder sub-metering and internal energy cost allocation. Fits cables up to 32 mm, installs in seconds. The lowest primary current option in the 3NJ6940 series.	View Product
3NJ6930-3BG12 Siemens 3NJ6930-3BG12 SENTRON NH1 Bushing Current Transformer PDF	A pluggable NH1 bushing current transformer for SENTRON 3NJ62/63 in-line switch disconnectors with fuses. 250/1 A ratio, Class 0.5 accuracy, 2.5 VA burden — legal-for-trade calibrated. Accepts cables up to 21 mm diameter. Compact 44×65×30 mm, 186 g.	View Product
3NJ6940-3BK22 Siemens 3NJ6940-3BK22 500/5A Bushing CT, Class 0.5 Accuracy f PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 500/5 A with Class 0.5 accuracy — the precision 500 A choice for sub-metering and internal energy cost allocation where billing is not required. Same 32 mm cable window, same tool-free plug-in installation as the calibrated 3BK23.	View Product
3NJ6940-3BL13 Siemens 3NJ6940-3BL13 600/1A Bushing CT, Class 0.5, Legal-for PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/1 A with Class 0.5 accuracy and legal-for-trade calibration. The 1 A secondary minimises voltage drop over long CT-to-meter cable runs — ideal for billing-grade metering where the meter is installed away from the switchboard.	View Product
3NJ6940-3BL11 Siemens 3NJ6940-3BL11 600/1A Bushing CT, Class 1 for Economic PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/1 A with Class 1 accuracy — the economical 1 A option for load monitoring and protection where the meter is located away from the switchboard. Fits cables up to 32 mm, tool-free plug-in installation.	View Product
3NJ6940-3BK23 Siemens 3NJ6940-3BK23 500/5A Bushing CT, Class 0.5 with Legal PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 500/5 A with Class 0.5 accuracy and legal-for-trade calibration — the certified 500 A choice for billing applications. Fits cables up to 32 mm, installs in seconds with no tools. For precision metering without calibration, see the 3BK22.	View Product
3NJ6940-3BL12 Siemens 3NJ6940-3BL12 600/1A Bushing CT, Class 0.5 Accuracy f PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/1 A with Class 0.5 accuracy — the precision 1 A choice for sub-metering where the energy meter is located away from the switchboard. Same 32 mm cable window and tool-free installation as the 5 A variants.	View Product
3NJ6940-3BL22 Siemens 3NJ6940-3BL22 600/5A Bushing CT, Class 0.5 Accuracy f PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/5 A with Class 0.5 accuracy — the precision sweet spot for sub-metering and energy monitoring where billing is not required. Same measurement performance as the calibrated 3BL23 without the certification cost. Fits cables up to 32 mm, installs in seconds.	View Product
3NJ6940-3BL21 Siemens 3NJ6940-3BL21 600/5A Bushing CT, Class 1 for Cost-Eff PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/5 A with Class 1 accuracy — the economical choice for load monitoring, protection confirmation, and non-critical current measurement. Same 32 mm cable window and tool-free plug-in installation as the higher-accuracy variants in the series.	View Product
3NJ6940-3BK21 Siemens 3NJ6940-3BK21 500/5A Bushing CT, Class 1 for Cost-Eff PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 500/5 A with Class 1 accuracy — the economical 500 A choice for load confirmation, overload detection, and non-critical current measurement. Same 32 mm cable window and tool-free installation as the precision variants in the series.	View Product
3NJ6930-3BF21 Siemens 3NJ6930-3BF21 SENTRON NH1 Bushing Current Transformer PDF	A pluggable NH1 bushing current transformer for SENTRON 3NJ62/63 in-line switch disconnectors with fuses. 200/5 A ratio, Class 1 accuracy, 2.5 VA rated burden. Accepts cables up to 21 mm diameter. Compact 44×65×30 mm footprint. Weight: 162 g.	View Product
3NJ6940-3BL23 Siemens 3NJ6940-3BL23 600/5A Bushing CT, Class 0.5 with Legal PDF	SENTRON 3NJ6940 pluggable bushing CT for 3NJ6 in-line fuse-switch-disconnectors. Rated 600/5 A with Class 0.5 accuracy and legal-for-trade calibration — the certified choice where energy measurements must stand up to billing scrutiny. Snaps onto cables up to 32 mm with no tools and no wiring changes. For precision sub-metering without calibration cost, see the 3BL22.	View Product