Langir DC Circuit Breaker

Langir is your leading supplier of reliable DC circuit breakers from China.

With decades of solid experience in the industry, Langir is an expert in DC circuit breakers whether for your home or your business.

If you are in search of the best supplier of DC circuit breakers, Langir must be your first choice of manufacturer.

Langir offers single pole, double pole, three poles, and four poles DC circuit breakers so you have more options.

Our DC circuit breakers also offer different amp ratings from 1 amp up to 63 amps with voltage ratings from 250 volts up to 1000 volts.

The easy snap-in mounting provides simple and quick installation saving time and cost for professional fees.

Langir DC circuit breakers are compliant with TUV Rheinland and approved by SAA.

And also conforms to the international standards IEC 60947-2, EN60947-2, and GB 14048.2.

Our DC circuit breakers are widely used for homes, businesses, factories, and for specific electrical devices that must be protected from short circuits and overloading.

With our DC circuit breakers, you are guaranteed that your appliance and other devices or equipment connected with it will have a long life and will keep their optimum performance for generations.

Langir greatest happiness is to cater to your needs and support your growing business.

Contact us for a free quote.

DC Circuit Breaker – FAQ Guide

In our guide for DC circuit breaker, you will discover what it is all about, its amazing purpose, and the applications where it is used.

You will also learn a piece of its interesting history as this guide will take you back in time to the important events that lead to the discovery of DC circuit breakers.

Moreover, this guide will also provide you with crucial information on the comparison between DC circuit breakers, AC circuit breakers, as well as fuses.

More importantly, you will learn the different standard codes which will give an in-depth understanding of how governing bodies put your safety first.

You’ll also be guided on the things you need to consider when choosing DC circuit breakers and their advantages.

So if you’re planning to purchase one, read our helpful guide first that we’ve put together just for you.

1. What is a DC circuit breaker?

DC circuit beaker

A DC circuit breaker is an operational electrical switch made to automatically prevent an electrical circuit from getting damaged by excess current due to a short circuit or overloading.

The DC stands for the direct current which is defined as an electric current that runs in one direction only.

It is also known as dc rated circuit breakers or circuit breaker for dc power supply.

Interrupting the current flow is its basic function once it detects a fault in the flow of the current and this function is also called OCPD which stands for Over Current Protection Device.

The DC circuit breaker operates once and generally must be reset so that it can resume its normal operation once again.

DC circuit breakers come in varying sizes; you can find small units that are used to protect low current circuits (for example for individual household appliances).

The dc circuit breaker price can be anywhere between $10 up to $30 and more depending from its types, size, and configuration.

Fun Fact: There was once a battle of currents that lasted for about a decade and even became a movie!

Between the years the 1880s and early 1890s, the “War of the Currents” or otherwise called the “Current War” became the most remarkable battle about currents in human history.

This is about a series of events that transpired between Thomas Edison and George Westinghouse concerning which electric power transmission delivery will be used in the US.

The events that happened during the current war were considered significant events that Hollywood even made a movie film using the same name in 2017.

In 1878, Thomas Edison realized that there is a market potential for bringing electricity directly to homes and businesses.

Therefore he developed a DC lighting system basing it on the 110 volt direct current which is relatively low to supply high resistance incandescent lamps he invented for the system.

But the main flaw of the DC lighting system is its short transmission range and it can only supply usable power just within a mile from the generator plant.

This means that the residents and businesses beyond one mile from the plant experience weak, irregular, or no electricity at all.

In 1885, Westinghouse developed a lighting system based on alternating current after he became aware of the new European AC based transformer systems.

Two years later the first AC power system with incandescent lighting was installed in Great Barrington, Massachusetts.

The multiple voltage power system can power up to 23 businesses situated along the main street of Great Barrington.

It uses transformers on 500 AC volts to step down to 100 volts so it can power the incandescent lamps, lower than the DC lighting system.

And in 1886, he built the first AC power system for commercial use in Buffalo, New York.

Now two electric power transmission systems are fighting over dominance in the same city.

At the peak of this war of the currents, Edison denounced alternating current after the death of a lineman who was electrocuted while working on a lighting pole using AC power lines.

The solution was to bury the high voltage lines underground, but Edison disagreed with this solution stating that it will only threaten more people’s lives.

He proposed to limit the AC voltage and he vowed that he will never use AC as long as he is in charge of his company (now Edison General Electric).

A publication even claims that there were a total of 87 deaths related to AC high voltage.

This was debunked by Westinghouse himself stating that his AC transformer system in households uses lower voltages than the direct currents and there were only 5 electrocutions by accident but zero in-home deaths.

It wasn’t until 1890 that this war ended with Edison leaving his company to focus on projects refining iron ore which mostly preoccupied his time.

After he left, his previous company started making AC based equipment and even dropping Edison’s name from the company’s name which he didn’t know until it happened.

15 electric companies were involved in this decade long war of the currents, but these companies merged throughout the years and only two remained dominant: General Electric and Westinghouse.

Thomas Edison and George Westinghouse

2. What is the development of the DC circuit breaker?

In 1879, Thomas Edison has thought about the idea of a circuit breaker.

During that time electrical networks are being fastly implemented in many industries.

This includes the lighting using electricity.

Edison realizes that short circuits usually happen with the ongoing installation of lighting in many large cities.

When this happens, it damages a bulb’s filament destroying it permanently and the cost of replacing it and repairing the lighting pole can be expensive.

He thought of two ways to mitigate short circuits:

• The first is to use a wired fuse that self destructs when a surge of high current happens.
• The second method is to use a mechanical device that will spring open when it detects excessive current.

The mechanical device’s contact can be reset manually.

He did many sketches of different fuse and circuit breakers in his scientific journals and he immediately patented the idea in the same year.

But in the end, Edison elected to use fuses.

Then in 1876, continuous inventions started to improve the initial models.

An industrial research laboratory was built by Edison around this time where he worked on his new inventions.

In 1898, the first circuit breaker was installed at the Boston Electric Light Company particularly in the L-street station.

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

The oil dampens the generated heat from the arc that forms between two open contacts.

In 1900, Granville Woods invented the automatic circuit breaker.

He is an African-American inventor who developed many improvements for the railroad industry.

Woods became famous for developing a way for the train station to communicate to the train conductors directly.

The first company to manufacture the first circuit breakers for mass consumption is the Cutter Manufacturing Company in Philadelphia in 1904.

It was under the name of ITE breaker (Inverse Time Element) and it became very successful.

Nowadays, you can find variations of ITE breakers.

For forty years, electricians and installers have had their standards for circuit breakers and their specifications.

It wasn’t until 1922, that AIEE Standards No. 19 was placed for the circuit breaker’s maximum heat limitations and other prohibited devices that are fire hazards.

DC circuit breakers were later developed.

And more than 100 years later, many electrical systems today are equipped with DC circuit breakers.

1898 oil breaker

3. To understand DC circuit breaker, how does electricity work?

To understand DC circuit breakers properly, you must understand how the electricity works first.

Some properties define a direct current or DC.

This is based on negatively charged particles called electrons that are being transformed into positively charged particles.

When these electrons move along the conductor which can be a copper or an aluminum wire, electricity is formed.

As mentioned earlier, the direct current only flows in one direction which means that the positively charged electrons move only in one direction.

4. How does the DC circuit breaker operate?

In general, the systems of circuit breakers have common operation features, but specific details significantly vary based on the current rating, voltage class, and the kind of circuit breaker.

At this point, we know that DC circuit breakers protect the electrical circuit including other devices that uses the power supply from getting damaged.

DC circuit breakers operate when it detects that the circuit is being threatened of becoming overloaded.

When it detects a fault, it quickly interrupts the electrical flow’s connection.

For example, an electrical power bar has a built-in circuit breaker.

If it has too many things that are using the power coming from a single source, the DC circuit breaker shuts off the power.

Therefore, it protected the electrical devices that are plugged into the electrical power bar.

This is commonly utilized on desktop computers.

A CPU can be damaged from a sudden power surge that is why a power bar protects it with a built-in DC circuit breaker.

CPU circuit breaker

5. Are there different ways how DC circuit breakers reset?

Yes, some DC circuit breakers are developed to reset in three ways:

• Manual DC circuit breakers

Once a manual DC circuit breakers kick in, if you’re near it, you would probably hear a click and the power supply is cut.

In a residence, when this happens, you would inspect the electrical panel.

It is the metal electrical and service distribution box and inside it could be several DC circuit breakers depending on how many electrical circuits you have distributed around your house.

You will find one or some DC circuit breakers’ lever flipped over and if you have enough knowledge about electrical circuits, you can inspect the cause of the problem.

Typically, you need to remove the plugs of your appliances and other items that are plugged in before you manually reset the DC circuit breaker, or turn the lever back to its normal position.

This will ensure that power is gradually restored to the areas of your home where power was lost.

It also helps you determine which appliance may have caused the circuit to overload.

• Automatic DC circuit breakers

The automatic DC circuit breakers are built to automatically reset.

When it trips, as the internal components down, it will attempt to reset the circuit or cycle.

• Modified DC circuit breakers

The modified DC circuit breakers are also referred to as trip and hold or modified reset.

The shortstop breaker cools down, and then the internal electrical contacts will try to re-connect which resets the circuit breaker automatically.

If there’s still an overloading or short circuit, the DC circuit breaker will trip again and repeats the cycle until the problem no longer persists.

Different types of DC circuit breakers in a fuse box

6. What are the chief parts of the DC circuit breaker?

The DC circuit breaker’s parts sometimes vary based on its type but the chief parts remain the same for most but may differ how their manufacturers label them.

The following are the commonly known chief parts of the DC circuit breaker.

• Molded case – The enclosure that houses the DC circuit breaker’s internal parts and keeps its other parts together. It has the base and molded case for the cover.
• Operating handle – The spring-assisted movable lever is used to turn the DC circuit breaker on/off and reset it.
• Trip button – This enables mechanically tripping the DC circuit breaker and is typically used to test the device.
• Terminals – Where incoming and outgoing load are connected.
• Contacts – Compose of moving and static contacts that break during short circuit or overloading.
• Overcurrent tripping device – A mechanism that detects overcurrent causing the breaker to trip.
• Arc extinguishing device – The device that quenches arc formation instantly.

Parts of the DC circuit breaker

7. What materials are used to make the DC circuit breaker’s frame?

The circuit breaker’s frame ensures that all the vital components are kept in place enabling proper execution of the operation and that it can be mounted appropriately.

The frame’s mechanical strength should be enough to withstand the quite large and possibly damaging current.

The circuit breaker’s frame should also provide insulation and separation of the current path, therefore, protecting you if you’re near the equipment during operation.

It is also one of the factors that support the DC circuit breaker to comply with standard codes.

There are two types of DC circuit breaker frames:

• Metal frame

Metal pieces are precisely cut, bolted, and welded together to create the frame for DC circuit breakers.

If you have older DC circuit breakers, you may find that they are placed in metal frames.

In fact, according to history, all DC circuit breakers that are below 600 volts were once called metal frame circuit breakers.

Metal frames are still being used for DC circuit breakers with higher voltages today.

• Molded insulating material

Most molded insulated frames are specially made from robust insulating materials like thermoset composite resins or glass polyester.

These types of frames are generally used for low voltage DC circuit breakers and the sizes are based on their ampere ratings.

For example for 12v dc circuit breaker, 12 volt dc circuit breaker, 24 volt dc circuit breaker, 24v dc circuit breaker, 48v dc circuit breaker, or 48v circuit breaker.

They are also present in insulated case circuit breakers.

But since the advances in materials and technology, you will now find molded insulated frames used for circuit breakers with 600 volts or higher like for din rail dc circuit breaker, 1000v dc circuit breaker or 1000v circuit breaker.

Old circuit breakers

8. What is the contact type inside a DC circuit breaker?

In a DC circuit breaker, the contacts provide the ways to connect the circuit with the unit as well as a way for separating a part of the circuit from the other parts of the unit.

As mentioned earlier, contacts are composed of fixed and movable contacts.

When the DC circuit breaker opens or closes, the movable contact moves to open or close (break or make) the circuit.

To operate the contacts requires a certain operating mechanism.

This can be mechanical only or a combination of power and mechanical.

Depending on the circuit breaker’s type, the operating mechanism can:

• Manually open and close the contacts
• On-demand open and close the contacts
• Automatically open the contacts

DC circuit breakers regardless of their size need help to move the operating mechanism so it can open or close the contacts.

This is where the spring is put into use.

Springs play a major part in opening or closing the contacts helping the circuit breaker mechanism to function precisely.

They are either relaxed or compressed to deliver the mechanical energy needed to help with the contacts’ opening and closing.

Typically, there are two forms of spring-assisted operating mechanisms:

• Manual over toggle

Manual over toggle is also called quick-break or quick-make type.

The speed of this type of operating mechanism is based on how fast the handle is moved.

There are motor operators that are used to automatically operate the handle in the absence of manual operation.

The handle is moved to open or close the circuit breaker, up to the point where the handle reaches the farthest position hence called over toggle.

Then the spring-assisted device automatically opens or closes the circuit breaker.

The manual cover toggle’s design allows the circuit breaker to trip open when needed, even if the handle is set in the closed or “on” position.

• Two steps stored energy

This is used when there’s a considerable amount of energy that is necessary to close the circuit breaker promptly.

The closing spring is charged and the energy is released to close the breaker.

It is designed to have a separate spring for opening and closing the circuit breaker and this allows the closing spring to move independently during the opening process.

This also permits an open-close-open cycle.

The motor can be activated remotely, it has quick reclosing with storing charged energy in a detached closing spring, and it provides safety due to the isolated charging of the spring.

DC circuit breakers in a control cabinet

9. What is the trip unit inside the DC circuit breaker?

A trip unit functions as the intelligence of a DC circuit breaker.

The DC circuit breaker needs to have some certain intelligence for it to automatically respond to command otherwise it would just be a fancy switch.

The purpose of the trip unit is to “trip” or open the circuit when the overcurrent conditions happen such as short circuit, thermal overload, and ground fault.

In general, trip units have two types:

• Electromechanical trip unit (thermal magnetic)

The electromechanical trip unit is commonly used in circuit breakers with low voltage.

It is mounted into the circuit breaker integrally and is sensitive to temperatures.

The thermal trip happens when overloading occurs, the load current heats the bimetal part, and with sustained overload; the bimetal deflects therefore tripping the operating mechanism.

While the magnetic trip happens when the current rapidly increases as it passes through the magnetic field causing the electromagnet to attract armature therefore the DC circuit breaker trips.

• Electronic trip unit

The electronic trip unit is composed of three internal parts which are the circuit board, current transformer, and flux transfer shunt trip.

The circuit board acts as the brains of the system because it can interpret the input current and make decisions based on set parameters.

The current transformer consistently monitors and reduces the current follow the appropriate input level.

While the decision to trip directs output to the flux-transfer shunt trip and therefore causing the DC circuit breaker to trip.

Old thermal magnetic interruptor on motor circuit breaker

10. What are the similarities and differences of AC and DC circuit breakers?

The DC circuit breaker is a relatively new technology.

Most homes are using AC and therefore, they use AC circuit breakers.

But aside from their differences, both have similarities as well.

Here are some of the AC and DC circuit breakers comparisons:

• Voltages

The DC circuit breaker is used with programmable logic controllers rated 24 VDC and 48 VDC and in applications such as wind power utility.

While AC circuit breakers, in general, are rated to interrupt beyond 6 kA.

Some manufacturers have dual rated circuit breakers; this means one unit is both AC and DC and rated from 48 VDC to 125 DC.

• Operation (arcing problems)

Both AC and DC circuit breakers look similar in appearance and operate in similar functions but they have different internal operations.

When there’s an overload, both of their internal contacts separate to protect the circuit.

However, all through the time that the contacts are drawing separately, an arc is formed.

This arc is the current that jumps across the gap and is therefore called contact arcing.

The contact arcing happens when circuit breakers are being opened or closed.

This arc has to be extinguished immediately otherwise it will continue to jump across the gap and the current continues to flow throughout the circuit.

When it comes to extinguishing the arc, AC and DC circuit breakers work differently.

AC circuit breakers are not designed to deal with arcing problems related to DC circuit breakers and this is why they are not interchangeable.

While DC circuit breakers are specially made to deal with arcing problems and they have additional measures to quickly disperse the forming electrical arc during opening and closing the circuit.

This is also known as DC arc suppression.

• Protection mechanisms

Both AC and DC circuit breakers have the same working principle when it comes to their thermal and magnetic protection mechanisms.

These protection mechanisms trip off both circuit breakers when they detect high current load, fault in the current, or short circuit.

• Versions

Both AC and DC circuit breakers have dc miniature circuit breaker and molded case versions.

Miniature versions work with currents lower than 100 amperes while molded case versions are usually larger and can have adjustable protection settings.

• Physical installations

The DC circuit breakers’ physical installations have a lot of similarities to the physical installations of AC circuit breakers.

DC circuit breakers possess a simple wiring method when compared to AC.

DC circuits are wired to a fuse box where cables are usually protected by sufficient metallic or plastic ducts.

This circuit can be connected directly to the DC device and controlled by a switch or it can also be a plug in electric outlet.

DC circuit breakers are then connected in series along with live conductors for every circuit.

And this is where AC is different since it has up to three live conductors, each with a different purpose and has to be connected to the right pole of the circuit breaker.

This can cause errors in connection which can lead to electrical accidents or cause motors to operate in the opposite direction.

While in direct current, all application just uses one live conductor.

And there are zero risks of getting consumed with connections.

There could be other similarities and differences between AC and DC circuit breakers not listed here, but you get the idea that both of them have their advantages suitable for specific applications.

11. How do you compare fuses and DC circuit breakers?

Any building needs to have DC circuit breakers set up as long as it is using electricity.

Even if you already have fuses installed, DC circuit breakers are still required.

They prevent power surges and prevent fuses from getting blown constantly.

Similarities of fuses and DC circuit breakers:

• Both share the same purpose since both provide short circuit and current overload protection.
• Both can be installed inside a fuse box.

Differences of fuses and DC circuit breakers:

• DC circuit breakers can be reset, while it is necessary to replace a blown fuse.
• They may provide the same circuits protection but they work differently:
  • Fuses are blown out cutting off the circuit once the accumulation of heat reaches the melting point, therefore, protecting the overloading circuit.
  • DC circuit breakers rely on the current magnetic effect for short circuit protection while via thermal current effect for the overload protection.
• Having DC circuit breakers is cheaper than the cost of replacing blown up fuses all the time.

Different sizes of fuse and a blown fuse

12. What you should consider when choosing the right DC circuit breaker?

There are important things that you should take into consideration when looking for the right DC circuit breaker.

Considering these factors will help in the ease of installation and prevent any issues later on.

Here are some of the things you can consider:

• Size of the DC circuit breaker

Choosing the size of the DC circuit breaker will depend on how big or small the unit is going to protect.

For example, for individual appliances, you can choose a small DC circuit breaker like the ones in power bars.

But if you need to power several neighborhoods, you will need to have large switch gears to protect the high voltage circuits.

• Type of protection mechanism

DC circuit breakers have thermal and magnetic protection.

Thermal protection is a mechanism that protects the circuit when it detects a higher rated electric current.

It is founded on a bimetallic component that can heat up, expand, and set off the DC circuit breaker.

When the current grows larger, it also works faster because more heat is generated which expands and opens the electric contact.

The magnetic protection sets the DC circuit breaker instantly when it detects a high fault current.

This is based on the rated breaking capacity of the DC circuit breaker, which denotes the determined fault current that it can interrupt.

Since the interrupted current is constant, it needs to open the electric contact more so that it can interrupt the fault current.

Magnetic protection also protects against short circuits, considerably larger than an overload.

It is important to confirm the circuit breaker specification is compatible with the electric supply current type otherwise it may not be able to guard the circuit effectively and there could be electric accidents.

• Electrical wiring adequate rated current

The electrical wiring connecting the electric device and the DC circuit breaker should have a sufficient rated current.

Even if you have chosen the correct DC circuit breaker, undersized electrical wiring can overheat which can cause its insulation to melt and reason for an electric fault.

Bimetallic strip bending

13. What are the advantages of using DC circuit breakers?

DC circuit breakers have plenty of advantages and these are:

• After the DC circuit breaker trips for fault, it can be manually reset instead of changing the unit, except if the large short circuit current has been cut off therefore it needs to be repaired.
• The DC circuit breaker has two parts of protective functions:
  • The long time suspension release with the reverse time features.
  • The rapid current release is used for both overloads and short circuits protections correspondingly.
• Aside from protection, many DC circuit breakers have smart features; they also have functions such as fault recording, communication interface, and electric quantity measurement to recognize integrated monitoring and supervision of devices and systems distribution.
• DC circuit breakers are specially made to deal with arcing problems and have additional measures to quickly disperse the forming electrical arc during opening and closing the circuit hence they have a longer device lifetime.

There could be other DC circuit breaker advantages that are not listed here but these are the most common and remarkable to think about.

14. What are the common types of DC circuit breakers?

There are numerous types of DC circuit breakers and they are categorized into three varieties, basic circuit breakers, the ground fault circuit interrupter (GFCIs), and arc fault circuit interrupter (AFCIs) circuit breakers.

1. Basic circuit breakers

The basic circuit breakers have four types, the single pole, double pole, triple pole and four poles circuit breakers.

• Single pole DC circuit breakers

Single pole DC circuit breakers are developed to detect the current of a single wire and trip in case a short or electrical overload happens.

They are built to distribute 120 volts to the circuit and accommodate between 15 up to 30 amps.

Most homes today have Single pole DC circuit breakers installed.

• Double pole DC circuit breakers

Double pole DC circuit breakers are made to simultaneously monitor the flow of electricity via two wires.

They are also called 2 pole dc circuit breaker, 2p dc circuit breaker, double pole dc circuit breakers, 4 pole dc circuit breaker, 2p dc mcb, or non polarised dc circuit breakers.

You can easily recognize them because they have two side by side switches interlinked in a single breaker.

They immediately trip if one from any of the two wires becomes overloaded or shorts out.

A double pole DC circuit breaker can deliver an electrical circuit with either 120/240 volts or 240 volts.

It can also accommodate 15 amps up to 200 amps.

Some of them are used in circuits supplying power to appliances that need a considerable amount of energy like a washing machine with a dryer.

• Three pole DC circuit breakers

Three pole DC circuit breakers are more practical to use than single pole DC circuit breakers.

For example, if there are three motors (with the same current ratings) within one machine that needs to be protected, it is more practical to use a three pole DC circuit breaker than using 3 single pole DC circuit breakers.

This will significantly reduce the installation time and the space requirements.

More importantly, in the event of load failure, all of the three loads will be disconnected from the voltage supply which will also include the non-faulty loads ensuring the complete machine shutdown.

• Four poles DC circuit breakers

Four pole DC circuit breakers, similar to the example of the three pole DC circuit breaker, are a more practical choice if you have four motors within one machine that you need to protect.

Another example is when you need to connect a backup generator into the switchgear.

So instead of disconnecting the generator’s neutral earth connection, you can use a four pole DC circuit breaker.

You can find operating currents rated 1000 V and 65 amps up to 25 amps.

2. GFCI circuit breakers

GFCI circuit breakers are developed to protect line to ground fault specifically when an unsafe electrical path transpires amongst a grounded element and an electrical current.

They are required by some electrical codes in residential homes specifically in areas that are prone to getting wet such as the bathroom, laundry area, and outdoor areas.

3. AFCI circuit breakers

AFCI circuit breakers are built to trip with the arcing is sensed within electrical wiring.

It sometimes happens on damaged electrical wiring or on thinning wiring insulation and these can be serious fire hazards.

The basic circuit breakers may not always detect electrical arcs since they are only tripped by extreme heat.

The AFCI circuit breakers are mostly mandatory as part of electrical code newly built homes.

Two pole DC circuit breaker, AFCI, and GFCI

15. What are the mounting methods used for DC circuit breakers?

The mounting methods for DC circuit breakers refer to how they are used in a single enclosure or an assembly.

The unit cost and ease of replacement are important factors that you should also consider when selecting a method for mounting your circuit breakers.

The mounting method may also depend on the type or the specific application of the circuit breakers.

DC circuit breakers are installed using any of the common mounting ways below:

• Fixed mounting method

In this mounting method, the DC circuit breaker is fixed mounted by hardwiring it onto the frame or bolting it in the enclosure or assembly.

This is considered the mounting method with the lowest purchase cost.

It is also front mountable and reliable making it appropriate for 600 volts and below.

When it comes to removing or replacing the DC circuit breaker, the power must be turned off first.

• Removable mounting method

In this mounting method, the DC circuit breaker has two parts, and these are the base and the actual breaker.

The base is bolted and hard wired to the frame while the actual breaker is plugged into the base.

In this method, you can replace the DC circuit breaker without the need to rewire it which saves time.

This method also has a moderate purchase cost, is front mountable, and has good reliability.

It is also applicable for 600 volts and below.

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

• Drawout mounting method

In the draw out mounting method, the DC circuit breaker has two parts as well, which are the base and the actual breaker.

The base is bolted and hard wired to the frame while the actual breaker slides into the base.

In this way, it allows the unit to be changed devoid of the need to remove the power being fed to the DC circuit breaker.

You can manually move the DC circuit breaker in or out or you can use a racking mechanism.

Although this mounting method seems more convenient, it has the highest purchase cost.

It is very reliable, near mounted, and allows power “on” testing.

This method is also appropriate for all voltages.

To remove or replace the DC circuit breaker, you need to turn off the power supply for safety.

But this method has an interlocked feature that automatically turns the power off when you try to remove the units.

A racking mechanism allows a DC circuit breaker to be moved.

Usually by ratcheting or turning a handle.

To rack the DC circuit breaker from the “connected” position, only the unit’s load must be turned off.

The built in interlocks do this hence the DC circuit breaker automatically opens before racking out starts.

The draw out mounting method does not require you to turn off all the power feeding the entire assembly just to service one DC circuit breaker.

Sample installation and removal

16. What is the purpose of DC circuit breakers on LED lamps?

LED lamps, as what the abbreviation stands for, works with Light Emitting Diodes and these can only operate with direct current.

This is why it is common that you see entire circuits working with direct current but this is only when LED lamps are the only ones connected.

And since the circuits are using direct current, DC circuit breakers are required for protection.

LED lamps are known to be very energy efficient, saving energy of up to 70% and other lighting technologies pale in comparison.

However, LED lamps sometimes tend to be a bit expensive and refunds are usually out of the question if they died out earlier than expected.

And because of this, it is very essential to protect them with DC circuit breakers.

It is also important to note here that LED lamps have AC and DC currents available.

The LED lamps that work with alternating current have an internal rectifier for alternating current circuit’s connection.

Home with LED lighting

17. What does a DC circuit breaker do in solar panels?

DC circuit breakers are usually found installed on solar PV (Photovoltaic) systems protecting some of its components.

Photovoltaic solar panels transform solar radiation into direct current.

This direct current can be used to power electrical devices.

The solar PV panels are wired in series of circuits, depending on its capacity, one installation can have more than one circuit.

Then all of the circuits are wired to a PV combiner box and each of them is connected to a DC circuit breaker.

This ensures that the solar PV panels are protected since they are considered the most costly components of the entire system that even just a small photovoltaic set up can already cost several thousand dollars.

If the solar PV system is using a battery bank, this is also connected to a DC circuit breaker to be protected.

If all the power produced by the solar PV panels is combined into a single DC output, there should also be a DC circuit breaker connected to it.

Another part that requires protection of the DC circuit breaker is the inverter, the one responsible for converting direct current to alternating current.

Lastly, if you have DC loads’ exclusive electric panel, a range of DC circuit breakers will be essential.

You have the choice to use the solar panels’ generated power to work with AC electrical devices as well as the installation of an electric inverter.

Home solar panel installation

18. What is the role of DC circuit breakers on electric vehicles?

Electric vehicles work with the use of a high capacity rechargeable battery instead of depending on fossil fuels.

The batteries are charged in charging stations that are built especially for electric vehicles.

These systems work with direct current, and because of this, they must use DC circuit breakers.

Electric vehicles are part of renewable energy technologies and their eco-friendly design provides a sustainable energy source for transportation.

Charging electric car

19. What is the use of DC circuit breakers in high precision industrial welding and machines?

The electric arc welding machines that work with direct current must have the protection of DC circuit breakers.

This is to guarantee the operation’s safety and ensure that no damage will happen to the welding machine.

DC circuit breakers are also generally used in electric motors that work with direct current.

These direct current electric motors have plenty of industrial applications.

They are known to have easy to learn controls, are integrated with automatic systems and have an instantaneous response time.

This is why direct current electric motors are ideal for industrial machine tools, automatons, as well as transportations such as rails and conveyors.

These types of machinery have control circuits that work with the direct current; therefore, they are protected with DC circuit breakers.

The control circuits and the power circuit are separated since they operate with different voltages, but each circuit is protected by its own DC circuit breakers.

The circuit that has a lower current rating and voltage is the control circuit since its only purpose is to process control signals.

Welding industry metal work

20. What are the standard codes that apply to DC circuit breakers?

Electrical standard codes promote safety for the person working with any type of electrical installation or maintenance job in homes or any other establishments, also the people occupying the area and the property itself.

Other codes are classified as national, state, or local with similar safety purposes.

Aside from that, these codes help building owners and cities avoid lawsuits complying with these sets of laws and guidelines.

• IEC 60364 (Electrical Installations for Buildings)

IEC 60364 is an international standard on electrical installations of buildings by IEC (International Electrotechnical Commission).

BS 7671 in the UK, a European wiring regulation, follows the IEC 60364’s structure with additional language to accommodate historic national practice and for the electricians and inspectors allowing them to have a simplified field use and purpose of compliance.

IEC 60364 provides standard rules about the installation and inspection of electrical systems.

Other national codes and guides refer to IEC 60364 to attain common objectives.

• BS 7671 (The Regs)

This is the national standard in the UK which stands for British Standard 7671.

It is also called the Requirements for Electrical Installations and IET Wiring Regulations.

This national standard in the UK which is aside from providing a standard for electrical installation also provides standards for electrical safety wirings and special installations and locations.

BS 7671 details the circuits delivered at nominal voltages which can be up to or may include 1500 DC or AC volts.

Therefore, this standard also details the Extra Low Voltage or ELV range (0 to 125 VDC and 0 to 50 VAC), and as well as the Low Voltage or LV range (125 to 1500 VDC and 50 to 1000 VAC).

This standard also includes the CENELEC technical substance agreements.

• CSA C22 (CE Code or Canadian Electrical Code)

The CSA C22 is the standard imposed by the Canadian Standards Association which covers the electrical equipment’s installation and maintenance in Canada.

This standard code is the basis for wiring guidelines across Canada.

A large body of volunteers produced this code and they are from the same industry and different government levels.

It outlines the wiring methods providing the acceptable prescriptive model.

But other wiring methods can be used but they have to be first accepted by the authority that enforces the standard code in your area.

However, this code is not applied to vehicles, communication utility systems, railway systems, ships, and aircraft because these installations have their code of standards.

• NFPA 70 (NEC or the U.S. National Electrical Code)

The NFPA 70 details the wiring and equipment safe installations in the US.

It is a locally adaptable standard and part of the NFPA which stands for the National Fire Protection Association.

Although called national, it was not a law but a typically adopted standard enforcing safe electrical practices.

It can also be amended, altered, or rejected in compliance with regional regulations created by local governing bodies’ voting.

Not to be confused with NESC that is used for communication utility and electric power systems for overhead and underground lines as well as power substations.

• UL489 and UL1077

UL 489 is the standard guideline for molded case circuit breakers while UL 1077 is for Supplementary Protectors for Use in Electrical Equipment.

Under the UL standards (Underwriters Laboratories), most devices for circuit protection should inspect and covered by their recognition or listing services.

UL tests the devices, generally 2 to 4 times annually ensuring that the materials and design used in the original recognized device remain consistent.

If the device has optional features like for example, auxiliary contacts, UL will require additional testing.

Other standard codes may be presently implemented in your area.

It is best to consult the governing authority in your locality or consult your licensed electrician if your chosen DC circuit breaker is compliant with minimum safety standards.

International standard code logos

21. Can you replace or install a DC circuit breaker yourself?

Unfortunately, the answer is no.

When working on electrical components such as DC circuit breakers, there are always precautionary measures to consider and it is not a job for anyone.

This is because installing or replacing the DC circuit breaker is a job for a licensed electrician which may even require a permit depending on your location.

As for the electricians, they are required to take proper precautionary measures and observe electrical codes.

Failure to do so can result in fires, electrocution, or sometimes death.

Electricians are also trained to conclude the type of circuit breakers that are required for your home.

Usually, DC circuit breakers are mounted in fuse boxes, and a rail specially designed for their installation is made for them.

DC circuit breakers protect individual direct current loads or protect main circuits like solar PV arrays, inverters, or battery banks.

Solar battery banks

22. How to find DC circuit breakers in China?

You can shop for DC circuit breakers online on your favorite manufacturer’s website, on online marketplaces, or by using any search engines and entering the keywords “DC circuit breaker”.

Generally, manufacturers have a product listing page where you can simply add your chosen DC circuit breaker to the cart, select the quantity, and input your payment details to check out.

But sometimes, to provide a personalized service, you can send an inquiry first.

For example, if you choose Langir as your DC circuit breaker supplier, simply fill out the free inquiry form and include your contact details.

A sales professional will get in touch with you using your provided contact details and will help you with your order.

Langir accepts small orders and big orders as well as urgent orders.

For small packages, they usually send them via express using services such as FedEx, DHL, UPS, TNT, and EMS which also means that these are door to door delivery services.

While for big packages, they usually send them by sea or by air.

Upon your order confirmation, DC circuit breaker stocks that have been inspected already are going to be shipped right away and you may probably receive your orders within 2 to 3 days.

Langir product storage facility ready for dispatch