Quick Summary:
DIN rail is a standardized metal rail used for mounting industrial control equipment inside equipment racks and enclosures. Defined by standards such as IEC 60715 and EN 50022, the most common type is the 35mm “Top Hat” rail (TS35). It allows for the rapid, snap-on installation of modular components like circuit breakers (MCBs), relays, and modular transfer switches (such as the Geya W2R), but is not suitable for heavy-duty switchgear like MCCBs or ACBs.
Introduction
In industrial electrical installations, efficiency and organization are paramount. A DIN rail is a metal strip of standard dimensions originally developed by the Deutsches Institut für Normung (DIN) in German. It has since become a global industry standard (IEC 60715) for mounting electric and electronic components in control cabinets.
Unlike traditional panel mounting, which requires drilling and tapping holes for each individual device, DIN rail systems allow installers to slide components onto the rail or snap them into place. This method significantly reduces installation time, simplifies maintenance, and allows for high-density configurations within electrical distribution boxes. However, while DIN rails are versatile, they have specific weight and size limitations that engineers must respect to ensure safety of installing and using.
Standard Types(Sizes) of DIN Rails
While there are several variations, the market is dominated by a few specific profiles.
1. TS35 35mm DIN Rail (Top Hat Rail)
TS35 is the industry standard. It is 35mm wide and comes in two primary depths:
- 7.5mm Depth: 35mm*7.5mm DIN rail is the standard choice for most lightweight control components.
- 15mm Depth: Used for heavier modular components that require greater rail rigidity.
- Application: This is the rail type used for the vast majority of Geya’s modular products, including the W2R and G2R Automatic Transfer Switches.
2. TS15 (Miniature Rail)
A 15mm wide rail used for smaller components, typically in junction boxes where space is extremely limited.
3. TS32 (G-Rail)
An older, asymmetrical standard shaped like the letter ‘G’. It is less common in modern installations but is still used for specific heavy-duty terminals requiring extra support against pull-out forces.
4. Different shapes of Din rail
In fact, to meet the increasingly complex installation environments and wiring requirements of distribution boxes, DIN rail manufacturers typically offer different designs besides the conventional “bowl-shaped” DIN rail, including those with brackets, angled brackets, and centerline designs.
What Can Be Mounted on DIN Rail? (The Modular Advantage)
DIN rails are designed specifically for modular equipment. “Modular” refers to devices designed with a standardized width and a rear mounting clip compatible with TS35 rails.
Power Switching and Protection
- Modular Automatic Transfer Switches (DIN Rail ATS): Devices like the Geya W2R and G2R series are prime examples of DIN-rail optimized engineering. These dual-power switches are compact and designed to snap directly onto a standard 35mm rail. They provide critical power redundancy without the massive footprint of traditional switching equipment.
- Miniature Circuit Breakers (DIN Rail MCB): The most common device found on rails, used for low-voltage circuit protection.
- Residual Current Devices (DIN Rail RCD/RCBO): Essential for leakage protection in residential and commercial boxes.
Control and Logic
- Relays: Geya offers a wide range of interface relays and time relays that mount securely to the rail, allowing for organized control logic wiring.
- Contactors: Modular contactors for lighting or heating control.
- Power Supplies: Many 24V DC industrial power supplies are designed with DIN rail mounts.
Critical Limitations: What Cannot Be Mounted on DIN Rail?
This is a crucial distinction for safety and compliance. DIN rails rely on friction and small plastic or metal clips to hold devices. They are not designed to support heavy weights or withstand the high mechanical torque generated by large fault currents.
Do NOT mount the following on standard DIN rails:
1. MCCB (Molded Case Circuit Breakers)
While some very small MCCBs have DIN rail adapters, standard MCCBs are generally too heavy and bulky. The mechanical force required to manually toggle an MCCB handle, or the magnetic forces generated during a short-circuit trip, can twist the DIN rail or snap the mounting clips. MCCBs should be panel-mounted (screwed to the backplate).
2. ACB (Air Circuit Breakers)
ACBs are massive devices used for main power distribution. They far exceed the weight bearing capacity of any DIN rail and must always be securely bolted to the chassis or installed in a draw-out cradle.
3. High-Current / Large Frame ATS
While the Geya W2R is perfect for the rail because it is a modular ATS (typically up to 125A), large industrial ATS units (e.g., 630A or higher) are not modular. These large units require significant heat dissipation and mechanical support that a DIN rail cannot provide.
4. High-Power SSR (Solid State Relays)
Small SSRs fit on rails perfectly. However, high-current SSRs require large, heavy heat sinks to dissipate heat. Mounting a heavy heat sink assembly on a rail is risky; it is often better to mount high-power SSRs directly to the metal backplate of the cabinet to utilize the cabinet wall for additional thermal transfer.
Material Selection: Steel vs. Aluminum vs. Copper
- Zinc-Plated Steel: The strongest and most common option. Recommended for installations involving Geya W2R/G2R ATS or banks of contactors, as steel resists bending under the weight of these devices.
- Aluminum: Lighter and easier to cut, but prone to flexing. Only suitable for very light loads (e.g., a row of small terminals).
- Copper: Generally used as a grounding busbar (PE), not for structural mounting of devices.
DIN Rail and Busbar Integration: Streamlining Power Distribution
While the DIN rail provides the mechanical foundation, the busbar (often called a comb busbar or mother line) provides the electrical efficiency. Understanding the synergy between these two components is vital for modern panel design. The DIN rail acts as the structural platform that maximizes the utility of the busbar.
1. Mechanical Support for Distribution
The DIN rail does not carry the main current itself, but it is the critical mechanical support system for power distribution blocks. Specialized busbar supports and neutral/ground terminal blocks are designed to snap directly onto the TS35 rail. This eliminates the need for engineers to drill custom holes or fabricate brackets to hold copper bars, significantly speeding up the assembly of power distribution systems.
2. The “Comb Busbar” Advantage
In modular applications, comb busbars (available in Pin or Fork types) are designed to work in perfect unison with DIN-rail mounted devices. Instead of using labor-intensive daisy-chain wiring to connect a row of MCBs or RCDs, installers can simply slide a cut-to-length busbar into the terminals.
- Efficiency: Using a busbar with DIN-rail mounted breakers can reduce installation time by over 30%.
- Reliability: It eliminates the risk of loose wire strands and reduces voltage drop across connections.
- Compatibility: Brands like GEYA design their modular breakers to accept these standard busbars, ensuring a secure fit that resists vibration.
3. Grounding Capabilities
While the standard DIN rail is primarily structural, it can play a role in the grounding system. When using specific grounding terminal blocks (typically green/yellow), the metal claws of the terminal bite through the rail’s surface coating. This effectively turns the steel DIN rail into a ground busbar for the chassis (PE), equalizing potential across the rail. However, for high-current grounding, a dedicated copper busbar is still required.
4. System Integration
The combination of DIN rails and busbars creates a clean, modular environment. Without the rail, busbars would require complex, custom-drilled mounting. With the rail, the entire power distribution assembly—breakers, busbars, and terminals—becomes a cohesive unit that is easy to inspect, expand, and maintain.
FORK 1P~4P 63A Busbar
Factory direct sales. The products are certified with CE and RoHS certificates, and are made of high-performance steel.
Installation Best Practices
- Cutting: Use a specialized DIN rail cutter to ensure a clean profile. Hacksaws often leave burrs that make it difficult to snap Geya devices onto the rail.
- Spacing and Heat: Even modular devices generate heat. If you are installing multiple power supplies or high-load relays side-by-side, check the datasheet. You may need to use DIN rail stoppers to create air gaps between devices.
- Grounding: While the rail is metal, do not rely on the rail itself as the sole grounding conductor for sensitive equipment unless the rail is specifically bonded to the earth system.
Conclusion
DIN rail is the foundation of modern, modular electrical design. It enables the easy integration of versatile components like GEYA’s W2R transfer switches and relays into compact spaces. Furthermore, when paired with busbar systems, the DIN rail transforms from a simple support strip into a sophisticated platform for efficient power distribution. However, engineers must recognize the physical limits of the system. For managing high currents and heavy equipment like MCCBs and ACBs, traditional panel mounting remains the only safe option.
If you are looking for a wide selection of DIN-rail compatible modular components, please contact us for the complete DIN rail catalog & quick and competitive quote!
Linked Read: GEYA Designed Star Related Products
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FAQs
What is a DIN rail circuit breaker?
A DIN rail circuit breaker, essentially equivalent to a Miniature Circuit Breaker (MCB), is a compact electrical protection device designed for mounting on a standard 35mm DIN rail (TS35 “top hat” type). It is primarily used to protect circuits from overload and short circuits and is commonly found in industrial control cabinets, distribution boxes, and equipment racks. GEYA offers a variety of DIN rail compatible MCBs, such as the GYM8, GYM9, and GYM10 series, which support quick snap-on installation and comply with IEC/EN standards.
How to mount a breaker on a DIN rail?
Installing a DIN rail circuit breaker is very simple and usually requires no tools:
Hook the upper fixing hook (clip) on the back of the circuit breaker onto the upper edge of the DIN rail.
Slightly tilt the circuit breaker and press down on the bottom until you hear a “click” (the spring clip locks into the lower edge of the rail).
Once securely fastened, it is ready for use.
To remove: Disconnect the power supply beforehand, insert a flat-head screwdriver into the bottom release tab, pry open the spring clip outwards, and simultaneously lift the circuit breaker upwards to remove it.
Where to buy suitable DIN rail circuit breakers?
It is recommended to purchase directly from professional manufacturers to ensure quality and compatibility. GEYA Electric offers a full range of high-quality DIN rail circuit breakers (such as GYM series MCBs, RCBOs, etc.) with worldwide shipping. You can visit the GEYA website MCB product page or contact us for the latest catalog and wholesale pricing.
