DIN Rail Dimensions

DIN rail is a standardized metal rail used for mounting industrial control equipment, such as circuit breakers, terminal blocks, power supplies, and relays, inside equipment racks and enclosures. The system’s global success comes from its precise and consistent DIN rail dimensions, which ensure that components from different manufacturers are compatible and can be easily installed on the same rail. This technical guide provides a comprehensive overview of standard DIN rail dimensions, material specifications, and their impact on system design and compatibility.

The Three Primary DIN Rail Dimensions

The term “DIN rail” originates from the German standards body, Deutsches Institut für Normung, which first published the specifications. While several variations exist, three profiles have become the most widely adopted international standards under IEC/EN 60715. These are commonly known as Top Hat, Mini Top Hat, and C-rail.

1. Top Hat Rail (TS35) – The Industry Standard

The most common profile is the 35mm wide “Top Hat” rail, formally designated EN 50022. Its shape resembles a top hat in cross-section, providing a secure and stable platform for a wide range of components. It comes in two standard depth variations, each serving a different purpose.

• 35mm x 7.5mm (TS35/7.5): This is the most prevalent of all DIN rail types. Its 7.5mm depth provides a strong, low-profile mounting surface suitable for the majority of standard components like terminal blocks, relays, and PLCs. Its shallow depth maximizes usable space within a control cabinet.
• 35mm x 15mm (TS35/15): Known as the “deep” or “high” Top Hat rail, this variant has a 15mm depth. The increased height is specified for mounting larger, heavier components such as high-current power supplies, contactors, or chassis that require greater clearance from the mounting panel. The deeper profile offers significantly more rigidity and strength.

2. Mini Top Hat Rail (TS15)

As its name implies, the Mini Top Hat rail (EN 50045) is a smaller version, with a width of just 15mm and a depth of 5.5mm. Its primary application is for mounting smaller components, such as miniature terminal blocks or compact interface modules, in space-constrained applications where a full-sized 35mm rail would be too large.

3. G-Section Rail (TS32)

The G-Section rail (EN 50035), also known as G-rail, features an asymmetrical, G-shaped profile. It is 32mm wide and typically 15mm deep. This design allows components to slide onto the rail from the side and provides a very secure mount, as the equipment hooks into both the top and bottom edges. It is often used for mounting heavier terminal blocks and other robust equipment, although it is less common today than the Top Hat profile.

A Comprehensive Look at DIN Rail Dimensions

The specifications for each rail type are tightly controlled to ensure global interoperability. The tables below outline the key DIN rail dimensions for the most common profiles.

Top Hat DIN Rail Dimensions (TS35)

Other Standard DIN Rail Dimensions

Material and Performance Characteristics

The material from which a DIN rail is made directly impacts its strength, weight, corrosion resistance, and electrical conductivity. These factors are crucial for ensuring the long-term reliability of the control panel.

1. Zinc-Plated Steel

This is the most common and economical material for DIN rails. A base of cold-rolled steel is coated with a layer of zinc through an electro-plating process, which provides good corrosion resistance for typical indoor industrial environments. The steel construction offers excellent strength and rigidity, making it suitable for supporting heavy loads without bending or deforming.

2. Stainless Steel

For applications in harsh environments, such as food processing plants, marine applications, or chemical facilities, stainless steel DIN rails are the preferred choice. The inherent properties of stainless steel (typically 304 or 316 grade) provide superior resistance to rust, corrosion, and chemical attack. While more expensive, they ensure the structural integrity of the mounting system in environments where plated steel would quickly degrade.

3. Aluminum

Aluminum DIN rails are significantly lighter than their steel counterparts, which can be an advantage in applications where weight is a primary concern, such as in aerospace or transportation systems. It also offers good corrosion resistance. However, it is not as strong as steel and has a lower load-bearing capacity, making it unsuitable for very heavy components.

4. Copper

Copper DIN rails are used for specialized applications where the rail itself needs to serve as a grounding busbar. Because copper is an excellent electrical conductor, it can provide a common ground path for all components mounted on it. These are typically used in conjunction with specific grounding terminal blocks designed to make electrical contact with the rail.

Compatibility with Mounting Systems and Accessories

The precise DIN rail dimensions are what enable a vast ecosystem of compatible components and accessories.

Component Mounting

The spring-loaded clip mechanism on the back of DIN rail-compatible devices is engineered to match the specific profile of the rail.

• Top Hat (TS35) Compatibility: A component designed for a TS35 rail has a clip that will securely latch onto the 35mm wide profile. The design of the clip ensures that it applies constant pressure, preventing the component from vibrating loose while still allowing for easy installation and removal with a simple tool like a screwdriver.
• G-Rail (TS32) Compatibility: Components for G-rails have a different mounting design, often featuring a hook on one side and a retaining screw on the other to lock it onto the asymmetrical profile.

Rail Variations: Slotted vs. Solid

DIN rails are available in solid or slotted versions.

• Solid Rails: Offer the maximum possible strength and rigidity. They are ideal for applications supporting very heavy components where bending cannot be tolerated.
• Slotted Rails: Feature elongated slots along their length, typically conforming to a standard pattern. These slots make it much easier to mount the rail to a back panel, as they provide flexibility in screw placement. While slightly less rigid than solid rails, they are strong enough for the vast majority of applications and can significantly speed up the panel assembly process.

Accessories

The standardized dimensions also support a range of useful accessories designed to fit perfectly onto the rail. These include:

• End Brackets (End Stops): These clips snap onto the rail at the end of a row of terminal blocks or other components. They prevent the components from sliding horizontally along the rail, especially in high-vibration environments or during transport.
• Separators and Markers: Thin plates that slide onto the rail to visually or electrically separate groups of components.
• DIN Rail Cutters: Specialized tools that provide a clean, burr-free cut of the DIN rail to a specific length without deforming its profile, ensuring components can still slide on easily.