Square Body fuses with aR characteristic are designed for partial-range protection of semiconductors and are typically combined with separate overload protection. The design follows DIN 43653 (type S, narrow module) and IEC 60269-4. The 1250V and 1500V versions are used where system voltage exceeds traditional 690V/1000V levels, for example in modern 1500VDC solar inverters, battery storage (ESS), DC charging infrastructure, traction and medium-voltage drives. The manufacturer’s catalog specifies rated voltage as an AC value – for DC applications, the time constant (L/R) and actual DC rated voltage should be verified against datasheets or the manufacturer per application.
Square Body 1250V – size 2Size 2 (S2M, 110 mm), breaking capacity 50kA, rated currents 250/350/400/450/630/710A
Application: Protection of semiconductors in medium-voltage inverters, drives and DC distribution up to 1250V. Center indicator for MK microswitch.
Square Body 1250V – size 3
Size 3 (S3M, 110 mm), breaking capacity 50kA, rated currents 315/350/450/630/1000A
Application: High-current protection of semiconductors in medium-voltage applications, ESS and industrial rectifiers.
Square Body 1250V – G-type with threaded pin
Size 3 (G3M, DIN 43653), breaking capacity 50kA, rated currents 315/500/575/630/710/800/900/1000A
Application: Same applications as S-type but with threaded pin for mounting on busbar via special screw.
Square Body 1500V – size 3
Size 3 (S3M, 140 mm), breaking capacity 50kA, rated currents 250/315/400/450/550A
Application: Protection of semiconductors in 1500V systems – modern solar inverters, DC charging infrastructure, battery storage (ESS) and DC distribution where system voltage is 1500V. Center indicator for MK microswitch.
Square Body 1500V – G-type with threaded pin
Size 2 (G2M), breaking capacity 50kA, rated currents 200/250A
Application: Lower currents in 1500V systems, threaded pin mounting.
| Property | Square Body 1250V (S2M / S3M / G3M) | Square Body 1500V (S3M / G2M) |
|---|---|---|
| Rated voltage | ~1250V (L/R = 2 ms) | ~1500V (L/R = 2 ms) |
| Time constant | L/R = 2 ms | L/R = 2 ms |
| Breaking capacity | 50kA | 50kA |
| Characteristic | aR | aR |
| Size | NH 2 / NH 3 (110 mm body length), DIN 43653 | NH 2 / NH 3 (140 mm body length), DIN 43653 |
| Rated current | 250–1000A | 200–550A |
| Indicator | Center indicator for MK microswitch | Center indicator for MK microswitch |
| Standard | IEC 60269-4, DIN 43653 | IEC 60269-4, DIN 43653 |
For part numbers, dimensions, power losses, time-current curves and DC data – see the respective datasheet.
Microswitch for signaling at fuse tripping:
– MK (2A, 250V) – microswitch for fuses type S-M and G-M with center indicator
– AMK1 – adapter for MK on 690V fuses
– AMK2 – adapter for MK on 1000V fuses (for higher voltage classes, contact the product manager for the current adapter)
Fuse holders and busbar accessories are available depending on application – see separate catalog.
Bolt-mounted semiconductor fuses in Square Body design for high-voltage AC and DC applications – ESS, solar inverters, charging infrastructure and medium-voltage drives.
Ultra-fast aR fuses according to IEC 60269-4 in voltage classes 1250V and 1500V protect IGBTs, diodes and thyristors against short-circuit currents in systems where 690V/1000V is not sufficient. Bolt connection on busbar provides low contact resistance and high thermal stability at continuously high currents.