What is the DC miniature circuit breaker(MCB)?

DC Breaker vs AC Breaker

The functions of DC MCB and AC MCB are the same. They both protect electrical appliances and other load equipment from overload and short-circuit problems, and protect the circuit. But the usage scenarios of AC MCB and DC MCB are different. It generally depends on whether the voltage used is alternating current states or direct current states. Most of the DC MCB uses some direct current systems like new energy, solar PV, etc. The voltage states of DC MCB are generally from DC 12V-1000V.

USFULL DC breakers use fireproof shells, which can stand high voltage and severe environments. Most solar projects will be put in the desert and wild areas hence we will offer you reliable products to keep good performance in such usage.

The USFULL DC Miniature Circuit Breaker/ DC MCB for solar is equipped with both a thermal and a magnetic tripping mechanism to protect DC electrical installations of solar and battery from overloads and short circuits. When a fault is detected, the circuit breaker automatically shuts down the electrical circuit to prevent wire damage and fire and also provide safety for your electrical installation. When performing electrical maintenance, the circuit breaker can also be manually opened whilst the full-rated load is flowing without causing any damage. The circuit breaker is designed for a reversible DC breaker connection and can be wired in either direction. It operates on a bidirectional current. The built-in indicator window allows you to quickly determine the contact position of the circuit breaker. The buckle design allows for simple installation on standard din rails, and provide easiness for DC breaker connection installation.

DC Breaker vs AC Breaker

DC isolator and DC circuit breaker differ depending on many factors such as the method of operation, device type, function, operation, current path, and trapped charge. Let’s discuss these factors in detail. The basic differences between circuit breakers and isolators include:

• DC isolator cannot disconnect a load or create a fault while a circuit breaker is designed to do so.
• A circuit breaker must always be operated in advance, as the disconnector is always operated after the circuit breaker.

Product Details

The USFULL DC Miniature Circuit Breaker is equipped with both a thermal and a magnetic tripping mechanism and has certification from CE and IEC standards.
The rated current of the USFULL DC MCB for solar is clear hence it is easy to read. For example, this picture shows the DC mini circuit breaker for 63 A (63 Amp DC breaker).

The DC mini circuit breaker is available in various operating voltage starting from:

• 12V DC breaker
• 24V DC circuit breaker
• 48V DC circuit breaker
• 250 VDC / 300 VDC circuit breaker
• 500 VDC / 600 VDC circuit breaker
• 750 VDC / 900 VDC circuit breaker
• 1000 VDC / 1200 VDC circuit breaker

The USFULL DC Miniature Circuit Breaker also has a built-in indicator window that aids in determining the contact position.

For 2P to 4P DC miniature circuit breakers, they are equipped with an invisible shorting bar and screw hole plug. Hence provide neat installation and safety from accidental disassembly after installation.

The contact material is from silver and electromagnetic coils and conductive parts are made of materials containing more than 99.5%, copper good conductivity, low temperature rises, and low resistance.

SPECIFICATION
FMB7 Series Circuit Breaker		FMB7N-63PV
Frame Degree Rated Current		63A
Pole		1P, 2P, 3P, 4P
Rated Operating Voltage (VDC)		12V, 24V, 48V, 300V, 600V, 900V, 1200V
Rated Current In (A)		10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A
Rated Insulation Voltage Ui (VDC)		1250VDC
Rated Impact Voltage Uimp (kV)		6
Ultimate Breaking Capacity Icu (kA)		6
Run Breaking Capacity Ics (%Icu)		100
Curve Type		C
Trip Type		Thermal-Magnetic
Mechanical	Actual average value	20000 times
	Standard value	8500 times
Electrical	Actual average value	2500 times
	Standard value	1500 times
Wiring Capacity (mm²)		In≤32A, 1.5~6mm²; In ≥40A, 10~16mm²
Ambient Temperature (℃)		-20℃~+70℃
Altitude		≤2000 m
Relative Humidity		≤9.5%
Pollution Level		2, 3
Installation Environment		No obvious shock and vibration
Installation Category		Class II, Class III
Installation		Standard din rail
Dimensions (W)*(H)*(D) (mm)	W	18	36	54	72
	H	98	98	98	98
	D	71	71	71	71
Weight (KG)		0.12	0.24	0.36	0.48

Advantages

The USFULL DC circuit breakers are suitable for DC breaker for solar and DC breaker for battery installation and have many advantages as follows:

Dimensions

The USFULL DC circuit breaker provides ample terminal heightening size, providing better creepage distance and better arc isolation.

Two-stage spring buckle for fast installation