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  • Tough on overloads and short circuits
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  • Quick trip action and super long service life

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Langir Electric - China Leading DC MCB Supplier
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  • Robust insulating materials for better and safer operation
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Langir DC MCB

The Langir DC MCB is your best choice for a reliable DC miniature circuit breaker that will provide optimum performance all the time without fail.

It is precisely designed and built to perfectly handle short circuits, overloading, power surges, or any electrical fault.

With Langir DC MCB you can be sure that your circuits are safe including you.

So Call Langir for your DC MCB now!

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What is Langir’s DC MCB?

The Langir’s DC MCB is your top choice for dependable miniature DC circuit breakers which will consistently protect your circuits and prioritize your safety.

What are the available options for Langir’s DC MCBs?

You can choose from 1, 2, 3, and 4 poles DC MCB types.
Langir’s DC MCB available amp ratings are from 1 to 63 amps.

Do does Langir deliver your DC MCB orders?

For small orders, Langir will use express delivery like FedEx, UPS, DHL, EMS, and TNT.
These deliveries are door to door service.
While for big orders, Langir will send them either via air or sea.
Langir will guarantee safe and protected order packaging to ensure that the DC MCBs will arrive in good condition and ready for installation.

How many days until you receive your DC MCB orders?

Langir keeps stocks of DC MCBs.
If there are enough stocks, your order will be delivered within 2 to 3 days upon confirmation.
But in the rare event that there is a shortage, you will be notified right away.
Langir will make sure that you will receive what you ordered complete and hassle free.

Does Langir provide a warranty for DC MCBs?

Yes, Langir provides 365 days warranty for all of its products.
But all Langir’s products are world class quality to ensure your satisfaction.

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Langir DC MCB Optimum Performance for Your Safety!

Langir is your #1 choice of DC MCB supplier from China.

When you order from Langir, you can trust that you are in good hands and you will only receive world class quality DC MCBs.

This is because Langir has been in the industry for decades now and has been a leading expert when it comes to circuit breakers and switches.

If you need a dependable DC MCB supplier, no need to look any further, you can always depend on Langir.

With Langir, you have more DC MCB options.

Select from single pole DC MCB, double pole DC MCB, three poles DC MCB, and four poles DC MCB.

Langir also offers various ampere ratings from 1 amp to 63 amps or from 250V up to 1000V so you can choose whichever is required for your circuits.

Our DC MCBs are easy to install with their slide in mounting method which only takes a couple of seconds.

Langir DC MCBs are approved by SAA, compliant with TUV Rheinland, EN60947-2, IEC 60947-2, and IEC 60947-2.

You can use our DC MCBs for the circuits of your home, business, as well as for circuits in factories and for any other electrical devices that need protection from an electrical fault.

Langir is committed to providing you with trustworthy DC MCBs that you can depend on for a lifetime.

DC MCB – FAQ Guide

Our guide for DC MCB will let you discover all the vital things about it, its purpose, and its various important applications.

You will also take a short journey back in time to learn about a piece of history and meet the amazing inventors responsible for the DC MCB’s development.

In addition, you will be provided with significant information about DC MCB, its advantages, and how it is compared to AC MCB and fuses.

Apart from that, you are going to learn about the things you should think through whenever you shop for your DC MCBs.

There’s plenty to learn about DC MCB which can help you save money, time, guarantee protection and safety.

That is why it is good to be wise and choose only the best DC MCB by using our guide before making any purchases.

1. What is a DC MCB?



A DC MCB stands for Direct Current Miniature Circuit Breaker.

It is an electrical switch that can be operated automatically to protect an electrical circuit.

It also protects the connected electrical objects from the damaging effects of short circuits, power surges, or any other fault in the circuit.

The DC MCB is also referred to as MCB for DC supply, MCB DC voltage, or MCB for DC current.

The type of current that a DC MCB is built for is direct current; hence it was named as “DC” that stands for direct current.

Direct current is best defined as a current that flows in only one direction.

The primary purpose of the DC MCB is to stop the current from running if a current fault has been detected.

After the DC MCB has taken action, it has to be reset manually to recommence its protective operation.

The DC MCB is available in different sizes and configurations.

The DC MCB price can cost around $10 and can cost as much as $30 depending on its brand, size, or its type.

2. Who is responsible for the development of the DC MCB?

The DC MCB is the result of the continuous development of DC MCB and AC MCB, AC and DC circuit breaker, and AC DC breaker over the years.

So to say that someone is directly responsible may not be technically correct.

But it can be credited to one person that you may have already heard of because of his monumental contributions in different fields specifically in the electrical field.

This person is Thomas Edison, an American inventor who, single handedly or with a company held the world record of 1093 patents and the person responsible for establishing the world’s very first industrial laboratory for research.

Edison is most famous for his incandescent light bulb invention as well as the motion picture camera and the phonograph.

And in 1879, he thought of creating a solution for short circuits was a rampant problem during that time and he called it the circuit breaker.

The fast expansion of electrical networks provided electricity to many streets in large cities.

However, this electrical revolution has its own problems like short circuits or power overloading.

This problem permanently damages the filament inside the bulb of the street lights and when this happens, the bulbs need to be replaced and sometimes more work has to be done a the result of the damage.

The constant replacing of bulbs and paying for repair services were expensive.

This is why there is an immediate need to find a practical and inexpensive solution.

Edison has thought about a couple of ways to alleviate short circuits and these are:

  • Use a wired fuse that will self destruct when power surges happen.
  • Build a mechanical device that will automatically spring open the moment that it detects overloading then can be reset manually.

Edison made a lot of sketches of these methods which he kept in his scientific journals.

After successfully developing his concepts, he immediately patented them.

However, Edison decided on using the first method instead which is the use of fuse to deal with the short circuit problem.

In 1876, Edison’s industrial research lab was established where he continued to create and improve his inventions.

Then in 1898, the Boston Electric Light Company installed the first circuit breaker in the L-street station.

This circuit breaker has an oil tank and upward breaking contacts that can be manually activated.

When the arc forms between the two open contacts, the oil diminishes the heat generated.

It featured upward breaking contacts that are manually activated and an oil tank.

The automatic circuit breaker was developed by Granville Woods, an African-American inventor, in 1900.

He is known for his contributions to the railroad industry such as the technology that enabled the train station to directly communicate to the conductor of the train.

Then in 1904, circuit breakers were first mass produced by the Cutter Manufacturing Company in Philadelphia.

These circuit breakers were named the ITE breaker which stands for Inverse Time Element.

In the following years, progress in technology was contributing to the development of the DC MCB that we know today.

Boston Electric Light Company and the oil circuit breaker

Boston Electric Light Company and the oil circuit breaker

3. How did the DC MCB evolve?

The DC MCB did not appear as it is when it was first developed.

There were several inventions of its kind that were tested and improved until it has become the kind of form that we see today.

The following enlists the significant eras that briefly detail the development of the predecessors of the DC MCBs.

  • 1960’s DC MCB
  1. Air circuit breakers

Air has been always used as an insulator in a switching device present in all ranges of voltage from miniature circuit breakers at low voltage to transmission voltages of air-blast circuit breakers rated at 800kV.

The term air circuit breaker is used to define the 3 phase circuit breaker where the insulators used are the air and atmospheric pressure.

Switches in the early times are only able to do a plain break of the forming arc.

The arc is stretched between the moving contact and the stationary contact and this means that there’s no arc control.

Furthermore, arcing times are long and there are limited current and voltage ratings.

Because of this, there were developments of different arc control devices and probably the best among them all is the arc chute.

The arc chute is composed of several plain metal plates that are organized in right angles to the arc chute’s length.

There are spacers in between the metal plates that cause the arc to separate into smaller arcs.

Because of this, the arc’s heat is extracted, and eventually, it diminishes.

  • 1970’s DC MCB
  1. Vacuum circuit breakers

The development of an interrupter that is capable of more fault detection and interruption resulted in the creation of vacuum interrupters.

However, the vacuum interrupter is sealed in a bottle for life and cannot be maintained.

The high vacuum’s dielectric strength is such that only 6mm contact travel is used at a 12kV rated voltage.

This made manufacturers halt any further developments in medium voltage air circuit breaker technology.

Vacuum interrupters were more expensive when compared to oil or air interrupters and this could be one of the reasons why they are not widely used even today even at low voltage.

Manufacturers designed maintenance free vacuum interrupters to offset its expensive cost.

This reduced its complexity and its size as a week.

But the operating mechanisms will still require regular lubrication, random checks, and resetting.

  1. Rotating arc SF6

The rotating arc interrupter is also an affordable device comparable to air arc control mechanisms but with similar satisfactory performance as the vacuum interrupters.

SF6 is a type of nontoxic gas that has high insulating properties.

During arcing, the SF6 decomposes and immediately recombines once the current is absent and returns to its dielectric properties.

During contact separation, the arc current is transported to a solenoid which is a copper strip turned several times.

This solenoid generates a magnetic field which allows the arc to go around its inner ring.

Because of the arc’s rapid movement through the SF6, the gas allows it to cool and it diminishes the moment of the first current zero even at high fault currents.

  • 1980’s DC MCB

After the last invention of interrupting devices, there are no new models that were invented.

But instead, further improvements were done to the current technologies.

Vacuum interrupters’ size was decreased and has become less expensive as well.

Almost all the new circuit breakers that were developed during this time have withdrawable designs.

A motor wound spring mechanisms were used on all medium and low voltage circuit breakers to decrease the size of charges and substation batteries.

These were the power source of the circuit breaker for it to open or to trip.

In place of the earlier solenoid, this time an electric motor charges the spring with a few amps for a few seconds.

A smaller solenoid releases a latch that releases the stored spring energy.

When the spring relaxes, it controls the mechanisms, the contact pressure is compressed, spring is opened, which connects the movable and fixed contacts of the interrupter.

On the other hand, the substation battery, despite having reduced its size, has become more complex in design.

It was possible due to the use of electronic protection relays that its mechanisms were reduced in size; however, this also created some circuit breaker problems as claimed by some manufacturers.

  • 1990’s DC MCB

During this decade, vacuum circuit breakers have emerged.

And by far, it was the most preferred technology for medium voltage primary substations.

This is due to the fact that it demonstrates almost zero failure rates plus it has become affordable.

The concept of fixed circuit breakers made a comeback with the emergence of air insulated SF6 circuit breakers and SF6 insulated vacuum circuit breakers

They are housed in a low voltage compartment with conventional mechanisms.

When the GVR pole mounted auto-recloser was introduced, it signaled the advancement in circuit breakers and proved to be as reliable as the interrupter.

It features a magnetic actuator mechanism plus other fundamental innovations which were the basis of new medium voltage circuit breakers developments.

  • 2000’s DC MCB

Circuit breakers will continue to evolve as new designs are always made from scratch.

Most designs aim to provide a simple and dependable magnetic actuator mechanism that is trouble free just like the latest interrupter technology.

New concepts are being applied to low and medium voltage circuit breakers, more compact than the last, replacing old technology with better and reliable DC MCBs.

Example of vacuum interrupter

Example of vacuum interrupter

4. What is the standard size of a DC MCB?

One unit of a DC MCB has a length of 89 mm and a width of 18 mm.

The width is multiplied if the DC MCB has two, three, or four units in one molded frame.

While the length of its side angle is 77.4 from the DC MCB’s back up to the tip of its handle.

While this is considered the standard measurements of the DC MCB, some manufacturers may use slightly different dimensions that do not affect its installation.

DC MCB dimensions

DC MCB dimensions

5. What are the different main parts of the DC MCB?

Although all the parts of the DC MCB play a vital role in its overall operation, several parts are considered primary and vital for DC MCB.

The following enlists the DC MCB’s different main parts and their brief descriptions.

  • Molded frame – This houses the DC MCB’s internal parts and maintains them in place. It is composed of a base and molded frame for the cover.
  • Handle – The lever you can operate to turn the DC MCB on or off and reset it.
  • Terminals – Where negative and positive wires are connected.
  • Contacts – Consists of fixed and moving contacts that break apart when upon detection of a current fault.
  • Electromagnet device – A device that energizes upon detection of overcurrent and causes the DC MCB to trip.
  • Arc extinguishing device – The device responsible for diminishing the formation of arc quickly.
  • Trip button – Enables you to mechanically trip the DC MCB if you need to test it.

Other parts that could be included are the latching mechanism, cable clamp, and tension spring.

DC MCB parts

DC MCB parts

6. Are DC MCBs made of durable materials?

High quality DC MCBs are generally made of durable and top standard materials.

DC MCB’s should have an enclosure that has enough mechanical strength that can survive damaging current.

It should have enough insulation and provide a path for separation of current that is vital for its safe operation.

The materials that are used to manufacture DC MCBs should also adhere to standard codes that are implemented in your area.

In general, there are two types of materials that are used:

  • Metal frame

These are accurately cut metal pieces that are bolted or welded together to form the frame for the DC MCB.

Earlier circuit breakers were all placed in metal frames hence they were also called metal frame circuit breakers.

Usually, the ones with metal frames are those with voltages ratings of 600V and below.

But nowadays, you may find metal framed circuit breakers with high voltage ratings.

  • Molded insulated frame

The majority of the molded insulated frames are from tough insulating materials such as glass polyester as well as thermoset composite resins.

Usually, these materials are used for DC MCBs with low voltage ratings.

However, these days, with the improvement of molded frame materials, they are also present in DC MCBs with higher voltages.

Old circuit breaker

Old circuit breaker

7. How do you reset a DC MCB?

Resetting DC MCBs may depend on what type you have purchased.

Not all can be manually reset as there are types that are reset differently.

Here are the most common DC MCB reset types and how they are done:

  • Manual DC MCB

When a manual DC MCB trips, the lever is flipped and the power supply is cut off.

If you know how to trace the connection of the circuit, you should try to inspect the problem and unplug any electrical devices or appliances that are connected to the circuit.

Any of those connected electrical devices or appliances could have caused the short circuit.

Check for any visible signs of problems such as burning smells, or burnt appliances or items.

Then flip over the manual DC MCB to its original state and observe the circuit.

If the DC MCB trips again, you should consider consulting an electrician to determine the cause of the problem.

  • Automatic DC MCB

Automatic DC MCBs are made to reset automatically.

When a current fault is detected, the automatic DC MCB trips and as its components cool down, it will start to attempt to reset itself.

  • Modified DC MCB

A modified DC MCB is also called the modified reset DC MCB or as trip and hold DC MCB.

After the modified DC MCB trips, the shortstop breaker lowers its temperature.

The electrical contacts will attempt to reconnect resetting the modified DC MCB automatically.

If it detects another short circuit or current overload, the modified DC MCB will trip once again.

This cycle is repeated until the current fault is no longer detected.

A tripped DC MCB

A tripped DC MCB

8. What is the different contact operating mechanism of the DC MCB?

Certain operating mechanisms are required to operate the contacts.

It can be by a mechanical operating mechanism or a combined action of mechanical and power.

The operating mechanism is dependent on the DC MCBs type and it can operate the contacts as:

  • Open and close manually
  • Open and close on demand
  • Open the contacts automatically

Regardless of the circuit breaker’s size, it needs the assistance of an operating mechanism for it to open or close the contacts.

That is why the spring has been included to basically become the device to assist the DC MCB for it to operate properly.

Springs are compressed to store and execute the required mechanical energy to assist in the contacts’ opening and closing.

Commonly, there are a couple of operating mechanisms that are spring assisted, and these are:

  • Manual over toggle

This is also referred to as the quick-make or quick break type.

Its speed is based on the speed of the handle’s movement.

If manual operation is not done, the motor operator automatically operates the handle.

The handle can be moved to its farthest point to open or close the circuit therefore it was called “over toggle”.

The built of its design enables the operating mechanism to trip even whenever needed when the handle is in the closed position (“on” state).

  • Two steps stored energy

When a significant amount of energy is required to close the circuit breaker immediately, two steps of stored energy are used.

In here, the closing spring is energized.

It stores energy and this energy is released so it can close the circuit.

The operating mechanism is built to have two springs, one for opening and another one for closing the circuit.

This design enables the closing spring to independently move during the opening process.

Also, because of this, it can perform an open-close-open cycle.

This provides added safety because the spring is charged separately, while the motor can be remotely activated, and the fast reclosing of the isolated closing spring with stored charged energy.

9. What are the types of tripping devices inside a DC MCB?

A tripping device operates as the brains of any circuit breaker.

Its main role is to open or “trip” the circuit when a short circuit or an overcurrent condition is detected.

Generally, there are two types:

  • Electromechanical tripping device (thermal and magnetic)

This is generally used in with low voltage DC MCB ratings even with DC MCB 10 amp.

The tripping device is built in and is designed to be temperature sensitive.

The thermal magnetic tripping happens when overloading occurs and the bimetal part is heated up.

If the overloading is sustained, the bimetal deflects and this trips the DC MCB.

On the other hand, the magnetic trip happens when the current that passes through the magnetic field rapidly increases and attracting armature hence the DC MCB is tripped.

  • Electronic tripping device

This tripping device has three inner parts and these are the flux transfer shunt trip, the circuit board, and the current transformer.

The brain of this tripping device is the circuit board because it can analyze the input current and create decisions basing on the registered parameters.

The current transformer works hand in hand with the circuit board since it always monitors the current making sure that it stays within the allowed input level.

While the flux transfer shunt trip decides when to trip and causes the DC MCB to do so.

Old thermal magnetic interruptor

Old thermal magnetic interruptor

10. What is the main difference between AC and DC MCBs?

AC and DC MCBs have the same purpose, they are made to protect the circuit and any electrical items connected to them.

However, they may work differently in some aspects, one cannot be used in replacement of the other as it may not operate properly and could cause more problems.

The main difference between the two is their de-energizing abilities, particularly arc formation and their process of extinguishing the arc.

Even when both have the same ratings, they do not have the same ability to turn on and off the circuit.

Using the AC MCB for direct current or DC MCB for alternate current could lead to cross level misoperation.

At every cycle, AC MCB has zero crossing point which makes it easier to extinguish the arc.

While DC MCB does not have it and this makes it difficult to extinguish the arc.

Therefore, it is required to install an arc extinguishing device.

This explains why the AC and DC MCBs are not interchangeable.

There are a few points to think about concerning this:

  • DC MCB has two main contacts while AC MCB has three.
  • The arc extinguishing device of DC MCB is usually a magnetic blowing type while for AC MCB; it is usually the grid type.
  • An AC open should not be used carelessly for DC operations, otherwise, it is most likely to produce short circuits with larger sparks.

Hypothetically, because AC and DC MCBs have different characteristics, they cannot be used in exchange for the other.

However, there are some special conditions where one can be used in replacement for the other temporarily but never permanently.

11. What is the difference between the DC MCBs and fuses?

Whether residential or business establishments, as long as they are using electricity, they need a circuit breaker installed.

Even when you are already using fuses, you still need DC MCBs installed as they are sometimes required by the regulations in your area.

Using DC MCBs not only protects the circuit but also protects your fuses from constantly blowing up.

DC MCBs and fuses are the same when it comes to:

  • Their purpose is both created to protect the circuits from current irregularities which can cause damage.
  • Their installations since both are generally installed inside a metal box.

DC MCBs and fuses are different when it comes to:

  • Resetting as both can be reset, but blown fuses need to be replaced.
  • Both can provide the same protection for the circuits but each work differently:
    • To protect the circuit, fuses are blown out after accumulating heat that reaches the melting point hence circuits are protected from overloading.
    • DC MCBs depends on the magnetic protection device for short circuit while thermal protection device for overloading protection.
  • Replacing blown up fuses tend to be expensive in the long run while DC MCB is a more practical choice.

Blown fuses

Blown fuses

12. What do you benefit from using the DC MCB?

Aside from protecting the circuits, DC MCBs provide other benefits that you may not know about.

Some of these are the following:

  • After tripping, there’s no need to replace it, you just need to reset it.
  • Some DC MCBs have intelligent features such as:
    • Fault recording
    • Communication interface
    • Electric quantity measurement to manage systems and devices distribution.
  • Additional protective measures to deal with arcing problems therefore DC MCBs have a longer service life.
  • Compact design which does not take up so much space.

Other benefits of using DC MCBs may not be listed here but these are the most important to know about what it can provide you.

13. What are the DC MCB pole types available?

The DC MCB poles vary depending on their types but they are easy to remember as the number of the pole is used as its name.

Here are the different DC MCB pole types:

  • Single pole DC MCB

The single pole DC MCB is generally used for the protection of a single wire circuit.

Despite being a single pole, this DC MCB type is still a reliable circuit breaker that will trip in the event of a short circuit or power overloading happens.

Typically, they are rated between 10 to 20 amps and built to handle 120 volts.

You can find DC MCB 32a, DC MCB 32 amp, 40 amp DC MCB, DC MCB 40a, DC MCB 63 amp or 12v DC MCB, MCB 12v DC, 24 DC MCB, and DC MCB 100v.

Many residential homes today have single pole DC MCB installed.

  • Double pole DC MCB

The double pole DC MCB is built to monitor the electricity flow of two wires simultaneously.

You can determine that the DC MCB is a double pole because it appears like two single poles joined together however, they are housed in one molded unit.

If any of the two wires have a short circuit or becomes overloaded, it immediately trips and cuts the power line of the two wires even if the other one does not have any issues.

Typically, this type of DC MCBs has either 120 or 240 voltage ratings and can handle 15 amps and as high as 200 amps.

They are generally used in circuits that provide power supply to appliances that need a significant amount of energy such as washing machines.

  • Three pole DC MCB

Three poles DC MCB have better practical use than the first two types.

One perfect example is if you need a circuit breaker for three motor equipment where three poles DC MCB is more sensible to use than 3 single poles DC MCBs.

By choosing this type, you will find that the installation time is reduced as well as the cost as well since you will most likely save more money.

The space required for the installation will be minimized considerably as well.

And in the event of current failure, all of them will trip off including the ones which do not have any detected current fault which will allow for a total equipment shutdown for safety.

  • Four poles DC MCB

Four poles DC MCB have the same practical use as the three poles DC MCB.

For instance, you have a generator that’s connected to the machine with three motors.

Instead of purchasing single poles DC MCBs or two double poles DC MCB, it is more practical that you use a four pole DC MCB instead.

You will find other similar applications where the four poles DC MCB is a better choice.

Different poles of DC MCBs

Different poles of DC MCBs

14. What are the key versions of the DC MCB?

DC MCBs have different key versions as well and these are based on their tripping or overcurrent characteristics or otherwise called the “trip curve”.

The key versions are the types A curve, B curve, C curve, D curve, K curve, and Z curve.

Among these types are three of the most common key versions and they are the B curve, C curve, and D curve.

Each type is engineered to be effectively responsive to the probable electrical surge’s strength in different settings.

  • Type B curve

This type of DC MCB is designed to trip when the detected current reaches 3 up to 5 times the rated load or its recommended maximum load.

It can be considered as the most sensitive type of DC MCBs and is normally used for domestic applications and commercial establishments requiring low voltage and where small current surges usually occur.

  • Type C curve

This type of DC MCB is commonly used where higher surges are likely to occur.

It is most common in commercial establishments or industrial facilities.

The DC MCB trips when it detects a current of 5 up to 10 times than its rated load.

  • Type D curve, D type DC MCB or D type

This DC MCB type is the least sensitive and only trips when it detects current surges that are 10 up to 20 times its rated load.

It is usually installed for heavy duty machines for commercial or industrial use since very strong power surges are likely to occur intermittently.

Some examples of the machines that need this type of DC MCB are large motors, welding equipment, x-ray machines, and power supply units that must not be interrupted.

There are other DC MCB types which are:

  • Type K

This type will trip if it detects power surges that reach 8 up to 12 times its rated load.

Usually, it is installed to protect the circuit of motors.

  • Z Type

This DC MCB type is known to be highly sensitive.

It trips upon detecting current surges that are only two to three times beyond its rated load.

But this characteristic makes it ideal for devices that are delicate and prone to short circuits.

For example, semiconductor devices.

Trip curves of DC MCBs

Trip curves of DC MCBs

15. What are the things you should take into consideration when looking for DC MCBs?

When looking for DC MCBs, there are a few things you should think about to make sure that you have chosen the right one.

By doing this, the installation will be easy and will save valuable time.

You can take into consideration the following factors:

  • The characteristics of the tripping mechanism
  • The breaking capacity pertains to the maximum current that the DC MCB can interrupt without releasing an arc.
    • More on the breaking capacity, the maximum current needs to match the possible strength of power surges in the installation vicinity.
    • It is measured in kiloamperes or kA and each kA is 1,000 amperes or amps which is the electrical current’s standard unit.
  • The number of poles within the DC MCB housing.
    • Options include single, double, triple, four poles.
    • They can break the circuits altogether even if the fault happened in just one circuit.
  • The DC MCB specification should be confirmed to ensure that it is compatible with the current type in your vicinity.
  • Adequate electrical wiring rating
    • The wirings that will be used for DC MCB connections must have the necessary rated current.
    • Undersized electrical wiring tends to overheat which can melt its insulation and cause an electrical fault.

Other factors can be taken into consideration such as the place of installation, the condition of the environment, and so on.

You can also consult a licensed electrician to inspect your area and determine the right DC MCBs to be installed.

16. How do you mount the DC MCB?

There are several ways on how you can mount the DC MCB whether in one enclosure or an assembly.

When mounting DC MCB you should also take into consideration the cost of each unit and the ease of replacement if they need to be replaced someday.

The DC MCB mounting types are:

  • Fixed DC MCB

Fixed DC MCB is front mounted fixed hardwired and bolted onto the frame of the enclosure.

This is known to have the cheapest purchase cost but the power supply must be switched off when the DC MCB needs to be removed.

The fixed DC MCB mounting method is applicable for 600 volts and below.

  • Removable DC MCB

The removable DC MCB has two parts which are the base and its actual breaker.

The base is hard wired and fastened onto the frame and the actual breaker is plugged into the base.

This mounting method can cost a little more than that of fixed DC MCB but it is also front mountable, and applicable to 600 volts and below as well.

When replacing the removable DC MCB, the power supply is turned off.

Ensure to turn off the power supply first before replacing the DC MCB.

  • Draw out DC MCB

Similar to the removable DC MCB mounting method, the draw out DC MCB also has two parts, the base and the breaker itself.

The base is also fastened onto the frame and hardwired as well while the breaker slides to fit into the base.

This type of mounting method enables repair or replacement jobs without the need to turn off the power supply.

The DC MCB is removed manually or a racking mechanism can be used to perform this task.

But despite the convenience that this mounting method can offer, it seems to be the most expensive purchase cost among the rest of the mounting methods.

The draw out DC MCB is near mounted, permits power “on” testing, and is appropriate for all voltage ratings.

You need to turn off the power supply to safely remove or replace the DC MCB.

But with an interlocked feature, the power supply is automatically turned off if any of the units are removed.

There’s a racking mechanism that removes the DC MCB usually by turning a handle or ratcheting.

The interlock feature racks the DC MCB from the connected state and turns off its power supply.

This feature allows you to service one DC MCB without the need to turn off all the power being fed to the entire circuit assembly.

Sample installation and removal

Sample installation and removal

17. Why does the DC MCBs are used for PV and ESS?

DC MCBs are required for PV or photovoltaic solar panels and ESS or electronic solar switch, an inverter.

It is stated in IEC 60364-7-712, an international installation standard.

Without the DC MCB installed the PV plug connectors are not protected against arcing and they can only be managed during load free conditions.

Although there is a recommended safety procedure to connect or disconnect the PV connectors, if these are disregarded, when a short circuit occurs, there is a high risk of arcing.

Not only that the DC MCB can significantly reduce the risk of arcing, it also protects the solar PV panels which are considered the most expensive part of the system.

The DC MCB can also protect the circuit connected to the battery bank and the ESS, which functions as the current inverter (DC to AC).

DC MCB is also installed if all the power generated by the solar PV panels is joined into one DC output.

Also, if you have an exclusive electric panel for DC loads; DC MCBs are required to protect them.

Solar panels installed on the house roof

Solar panels installed on the house roof

18. How do you store DC MCB units properly?

When storing DC MCB units ensure that you place them inside a container or a box that will be able to protect them properly.

DC MCB orders generally come inside a box packaging, so you can leave the units that you will not use inside their boxes.

Then place them in cabinets or shelves that are cool and dry.

As much as possible, do not place heavy objects on top of them since doing this could damage the box packaging and could also damage the units.

Avoid leaving the DC MCBs out in the open or leaving them outdoors.

As too much exposure could cause exterior damage or too much heat could melt some of its parts.

This could cause the DC MCBs to not work properly which is not good.

That’s why you should consider properly storing DC MCBs to avoid issues in the future.

This will also make sure that the quality of the DC MCB is protected.

19. Can you work on a DC MCB by yourself?

Working with any live current is prohibited in some countries.

You must check first with your locality about the regulations when it comes to circuit breakers.

It is always best recommended to hire a licensed electrician if you need to install or repair your DC MCBs.

Aside from following the regulations, there are standard codes to be observed as well.

Trained and experienced electricians are knowledgeable about the standard codes applicable to your country.

These standard codes are mandatory to ensure safe and proper installation.

Otherwise, untoward accidents such as electrecution can happen.

20. How do you look for DC MCB suppliers and purchase them?

If you would like to find suppliers of DC MCBs, all you need to do is to search for them online.

You can use a search engine and type in the keywords “DC MCB supplier” or “DC MCB manufacturer”.

But if you already have a manufacturer in mind, you can simply visit their website and order from there.

For instance, you have decided to choose Langir as your DC MCB supplier, you can visit Langir’s website.

You can fill out an inquiry form or contact Langir using their contact information.

A trained salesperson will get in touch with you about your inquiry.

You may discuss specific details about your DC MCB order such as the type you need, the quantity, and the cost.

Langir keeps high quality stocks ready for dispatch.

You will be advised via email if your order has been confirmed.

If there are enough stocks, your order will be dispatched right away to be sent to you.

On average, the delivery time is anywhere between 2 to 3 days but this depends on your location’s distance from the nearest Langir factory.

Otherwise, you will be advised if there are any changes with your order delivery times.

Rest assured, Langir will deliver high quality DC MCB orders as soon as possible and ready for installation.

Langir DC MCB with SAA and TUV Rheinland seals

Langir DC MCB with SAA and TUV Rheinland seals

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