| Categories | Economic 4.5KA, 6kA Regular Series Circuit Breaker |
| Model | SFM3-125 DC 125A |
| Rated current(A) | 1,2,3,4,6,10,16,20,25,32,40,50,63 |
| Frame size Rated current(A) | 63A, 125A |
| Number of poles | 1P, 2P |
| Breaking current | 10000 |
| Time costant | 10 |
Application
● The maximum ambient air temperature does not exceed +40C, minimum is not less than -5C,and the average value does not exceed +35C.
● The altitude of the installation site does not exceed 2000m.
● The relative humidity of the atmosphere does not exceed 50% at the maximum ambient temperature of +40C. Relative humidily at high temperatures can be relatively high. The monthly average maximum relative humidity of the wettest month is 90%, and the monthly average of the month The minimum temperature is +25C and takes into account condensation that occurs on
● Pollution levelis 2.
● Installation categories are I, II.
● Use TH35- 7.5 steel mounting rails for installation.
● The inclination of the mounting surface and the vertical surface does not exceed 5°.
● Screw the wire tight.
Construction and Feature
SFM3-DC DC circuit breaker is composed of outer casing, operating mechanism, thermal release,electromagnetic tripping contact system, arc extinguishing system, etc. It has overload and short circuit protection functions, unique design structure and powerful permanent magnet arc extinguishing system. The product has a short circuit capability of 10kA and a mechanical life of more than 20,000 times. The appearance of the product is beautiful. The mounting rail is a TH35-7.5 standard steel mounting rail, and has the following features: the handle is designed on the front side of the front end, and the operation is safe and strong. Feel comfortable, be sure to pay attention to the "+, -" polarity when wiring, the power supply goes in and out, in line with the characteristics of the power supply line, easy to install, saves the wire.
Technical Data
| Table 1 | ||||||
| Frame size rated current | Pole | Rated voltage | Rated current | Rated ultimate short circuit capability | Instantaneous release current | |
| Breaking current | Time constant | |||||
| 63 | 1 | DC250V | 1,2,3,4,6,10,16,20,25,32,40,50,63 | 10000 | 10 | 8ln-12ln |
| 2 | DC500V | |||||
| 125 | 1 | DC250V | 80,100,125 | 10000 | 10 | 8ln-12ln |
| 2 | DC500V | |||||
Standard time-current
| Table 2 | ||||||
| Test | DC test current | Initial state | Time limit | Expected result | Remark | |
| a | 1.05ln | Cold state |
t≥1h(ln≤63A) t≥2h(ln>63A) |
No tripping | ||
| b | 1.3ln | Right after test number a |
t<2h(ln>63A) t<1h(ln≤63A) |
tripping | ||
| c | 8ln | Cold state | t≥0.2s | No tripping | ||
| 12ln | t<0.2s | tripping | ||||
Wiring diagram

Dimensions

> Does a Float Switch Need IP68 for Hot Water?
A Float Switch with IP68 sealing, AC 220V rating, and 60°C water temperature tolerance — built for reliable liquid level control in pumps and tanks.
> Does a Circuit Breaker Need Both Overcurrent and Leakage Protection?
A magnetic RCBO that combines overcurrent and earth leakage protection in a compact two-module design — featuring 10kA breaking capacity and CE approval for resident...
> What Makes the ASFT Series Outperform Other Float Switches?
A float switch with integrated square-axis multi-pole design, welding-process contacts with silver solder pads, and bite-process terminal blocks — built for reliable...
> How Does a DC Series Circuit Breaker Speed Up Fault Finding?
A DC series circuit breaker with 1-63A ratings, 10kA breaking capacity, 6.2kV impulse withstand, and central-staying trip indication — built for reliable low-voltage...







