The 25 A rating holds flat from 30 °C through 40 °C — no derate needed in a standard 40 °C panel. At 60 °C it still carries 22 A, which is better than many compact MCBs that drop harder above 50 °C. The single-pole design switches the line only; neutral is through-bar, so this is for a single-phase branch or a 1-pole lighting/control circuit, not a multi-pole motor feed.
Siemens 5SJ4125-6HG40 SENTRON MCB, 1P, 25 A, 70 mm depth
MPN5SJ4125-6HG40
Active
Siemens SENTRON 5SJ4125-6HG40, miniature circuit breaker, 1-pole, rated 25 A at 40 °C, 70 mm depth, 18 mm width, IP20/IP40.
$76.52Ref. price · indicative, final on quote
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026
Specifications
| Parameter | Value |
|---|---|
| Product designation | Miniature circuit breakers |
| Brand name | SENTRON |
| Number of poles | 1 |
| Pole design | 1P |
| Application suitability | Mechanical engineering / industry |
| Parameter | Value |
|---|---|
| Tripping characteristic class | B |
| Overvoltage category | 3 |
| Parameter | Value |
|---|---|
| Mounting position | any |
| Fastening method | on standard mounting rail |
| Combined terminal, top | Yes |
| Combined terminal, bottom | Yes |
| Width | 18 mm |
| Height | 90 mm |
| Depth | 70 mm |
| Installation depth | 70 mm |
| Modular width units | 1 |
| Torque, min. | -40 °C |
| Torque, max. | 75 °C |
| Sealable | Yes |
| Parameter | Value |
|---|---|
| IP protection class | IP20, with connected conductors, IP 40 in the handle range |
| Pollution degree | 3 |
| Halogen-free | Yes |
| Silicone-free | Yes |
Product details
Frequently asked questions
Where can I buy 5SJ4125-6HG40 and how do I get a price?
This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ through this listing.
What is 5SJ4125-6HG40's depth and width?
Depth is 70 mm, width is 18 mm — one standard modular unit. Height is 90 mm.
Will 5SJ4125-6HG40 drop into a panel specified around 5SL4363-7 without rewiring?
Both are 1-pole Siemens MCBs on the same 18 mm DIN-rail footprint, so mechanical fit is the same. However, the 5SJ4 series uses combined terminals (screw-clamp) while the 5SL6 uses tunnel terminals — verify the lug type on the existing wiring before ordering. The 5SJ4125-6HG40 has combined top and bottom terminals; tunnel terminals are not available.
MPN
5SJ4125-6HG40