Electrical Enclosure Selection
A guide for the selection of electrical enclosures, electrical cabinets and 19″ rack cabinets
Scope and Application
This selection guide is intended to provide guidance and clarification to assist with the selection of electrical enclosures, electrical cabinets and 19″ rack cabinets. Following this guide will help to optimise the life of enclosures and internal components.
This selection guide applies to empty enclosures for low voltage switchgear and controlgear assemblies in accordance with IEC/EN 62208 where the rated voltage does not exceed 1000 V a.c. at frequencies not exceeding 1000 Hz or 1500 V d.c. For design and verification information for assemblies, refer to comments regarding electrical enclosure assembly in accordance with IEC/EN 61439 Low voltage switchgear and controlgear assemblies.
Industry 4.0, the current era of digitalisation of the manufacturing sector, is reflected in the rise of data, increased connectivity, analytics, automation, and human-machine interaction. As a result, the traditional electrical industry has become a hybrid environment. A traditional electrical enclosure with DIN rail mounting now may also require EIA-310-D 19” rack mounting. The 19” rack system offers flexibility that can be used for a wide variety of applications including housing data/IT equipment (servers, routers, switches, hubs), audio/visual (AV), electrical/electronics and battery storage. 19” rack cabinet design considerations are based on a 19” rack configuration as defined in the Electronic Industries Association EIA 310-D Standard for 19” racks, panels and associated equipment. The EIA 310-D 19” mounting flange defines the front internal mounting surface within the rack, enclosure or cabinet that provides a mounting surface for computer servers, electrical equipment, chassis guides, side rails, and/or panels.
As our range of 19” rack cabinets are used in the electrical industry within this hybrid environment, and therefore also function as electrical enclosures, they are classified as electrical enclosures. Our range of 19” rack cabinets conform to and are fully certified electrical enclosures to IP55 IK10 or IP66 IK10 to IEC/EN 60529, IEC/EN 62208, EIA-310-D, RoHS, CE and UKCA.
How to choose the best electrical enclosure to suit design needs
There are many factors to consider when choosing an electrical enclosure or electrical cabinet.
Step 1. Determine the IP Rating to suit the application
Step 2. Select the material to suit the environment
Step 3. Calculate the size to suit equipment and component layout
Step 4. Calculate thermal management requirements
Step 5. Add internal and external accessories
Step 6. Select the mounting option
Step 7. Address security and access lock requirements
IP Ratings
An important decision when choosing an electrical enclosure, electrical cabinet or 19″ rack cabinet is to select the IP ingress protection rating and IK impact rating. Ingress protection IP ratings are defined in IEC/EN/AS60529 as a two-digit code detailing the degree of protection against mechanical impact and protection against contact with live parts, ingress of solid foreign bodies and water. The degree of protection table is shown on our website and in our catalogue.
Our range of enclosures are designed to provide protection in the harshest conditions. Our single door enclosures are IP66 IK10 while our double door enclosures are IP55 IK10. For food and beverage applications, we also have IP69K hygienic enclosures. In addition to considering the IP rating of the enclosure itself, it is also important to consider the need for adequate ventilation and the IP rating of the ventilation components. The IP rating of IP Enclosures fans and filters is IP54 with optional upgrade to high performance filters providing IP55 protection. The overall IP rating of the ventilated enclosure assembly is equivalent to the lesser IP rating of the enclosure and ventilation components.
As 19” rack cabinets are often used for battery storage, it is important to ensure that if used for this application, the cabinets should be adequately ventilated and kept cool.
Materials
Material is selected based on the application, environment and location. Factors impacting selection may include strength of materials, resistance to corrosion, thermal stability, resistance to UV, mechanical impact and lifting requirements. Enclosures should be constructed of materials capable of withstanding the mechanical, electrical, thermal and environmental stresses to be encountered in service conditions. This includes protection against corrosion by use of suitable materials or by protective coatings. IP Enclosures supply powder coated galvanised steel enclosures for general industrial applications, 304L & 316L stainless steel, and marine grade aluminium enclosures for extreme duty applications that require high corrosion resistance. We only use high quality materials from European mills.
For installations with high levels of exposure to chemical or chemical cleaning, it is recommended to check for chemical compatibility using a chemical compatibility resistance table. Surface protection and surface finish or roughness is also a factor for consideration.
For installations in coastal saltwater environments, it is important to select suitable materials to withstand increased risk of corrosion. Marine grade aluminium, 316L stainless steel, and non-metallic enclosures are suitable materials of choice for saltwater coastal environments. Atmospheric conditions can create environments where tea staining on stainless steel may occur. The relationship between the contributing factors are complex, but generally become increasingly critical closer to saltwater. Tea staining occurs as a result of local conditions (such as temperature, relative humidity and presence of corrosives on the surface) being too aggressive for the selected grade of stainless steel. To prevent tea staining, it is recommended to wash the enclosure regularly to remove deposits (such as salt and industrial pollutants) that may cause corrosion.
Size
The size of the enclosure is determined by the components and cables being housed. This includes minimum distances around components and cables. It is important to check the installation diagrams of the housed components to ensure minimum distances between and around components are maintained with regards to electrical clearances, airflow and maintenance accessibility. When sizing enclosures, the distances between a barrier or enclosure and the live parts they protect should not be less than the values specified. When specifying size, we typically specify as height x width x depth in mm. Wall mounted electrical enclosures range in size from 300H x 200W x 150D to 1200H x 1200W x 400D while floor standing electrical cabinets are available up to 2020H x 1200W x 800D.
To select height of 19” rack cabinets, rack mounted equipment is measured in U or RU. Rack height is defined by unit height, ‘RU’ or ‘U’. One ‘U’ is equal to 44.45mm. Most IT servers, network switches and other peripherals are 1U to 2U in height. Rack mounted UPS systems are typically 2U. Height is determined by adding up the U height of all equipment housed. If the total required height is 20U, then the next available height in our range being 24U would be selected as a minimum. However, to allow for future expansion and airflow, a 32U may be required. Our 19” rack cabinets range from 4U to 42U (and double bay 2 x 42U).
Selecting a 19” rack cabinet with the correct depth is important. It is important to consider the length of the equipment, battery or server chassis, as well as allowing additional clearance at the front and rear for cable management; and clearance in the front for the chassis bezel and handles. For example, while some equipment may be mountable in 600D cabinets, handles and cables may prevent the enclosure door from closing properly, or airflow may be impacted, therefore 800D may be required. To calculate the depth required, we need to understand the depth from EIA Flange to the PCI (Peripheral Component Interconnect) Bulkhead. Some equipment may require approximately 50-75mm between the front of the EIA Mounting Flange and inside of the enclosure front door. This allows for handles and air circulation throughout the cabinet. To accommodate various depth requirements, the EIA Flanges are depth-adjustable. Typically with the 4-post rack type, the front flanges remain fixed while the rear rails are adjusted to suit.
Weight should also be considered. Our standard 19” rack cabinets are capable of supporting 15.9kg of products per EIA unit (U). The heavy duty range can accommodate 20kg per EIA unit (U) up to a total of 840kg for a 42U 19” rack cabinet. Batteries can weigh up to 60kg each therefore care should be taken not overload the cabinet. For this reason, if the 19” rack cabinet is being used for battery storage, a heavy duty 19” rack cabinet should be selected.
When determining H (U), W and D, thermal management requirements including airflow should be considered.
Thermal Protection
To manage the climate within electrical enclosures, we need to understand the conditions and calculate accordingly. The internal temperature is controlled by transferring heat into or out of the enclosure. The application, environment, location, size and installation will influence the design of the thermal management solution.
We provide integrated climate controlled electrical enclosure solutions. Our electrical enclosure climate protection product range includes fans, filters, heat exchangers, air-conditioners, anti-condensation heaters and controllers. For more information on thermal management product selection, refer to IP Enclosures Climate Protection: Industrial climate control technology for electrical enclosures and data racks.
For 19” rack cabinets, in addition to details outlined in ‘IP Enclosures Climate Protection: Industrial climate control technology for electrical enclosures and data racks’, some 19” rack mounted equipment requires front to rear cooling. It is therefore important to ensure adequate air circulation at the front of the cabinet. In addition to bottom to top, front to rear airflow also needs to be considered.
Adequate ventilation and cooling is required for battery storage applications. Battery storage installations often consist of multiple interconnected batteries. A build-up of gases (hydrogen and oxygen) from these batteries can result in a significant safety hazard. It is necessary to provide ventilation to mitigate associated risks. Ventilation and cooling also helps to maintain the life and performance of batteries.
Accessories
IP Enclosures supply a wide range of accessories. Our range of electrical enclosures and electrical cabinets are designed with studs and encapsulated nutserts to enable mounting and fitting of accessories without the need for drilling to ensure that the integrity of the IP rating is maintained.
An inner door escutcheon is an optional accessory that can be easily fitted into our new or existing electrical enclosures. It is important to check the depth of the enclosure to ensure that the minimum distance between the electrical components and inner door is maintained. Wall-mounted enclosures up to 400mm deep are available to ensure large components can be safely housed behind inner door escutcheons. Dimensions are shown on the website and data sheets.
DIN rail kits are designed to be easily fitted to IP Enclosures steel and stainless steel electrical enclosures without drilling. The separate internal chassis frame can be fitted with components and wired prior to assembly into the enclosure. The removable escutcheon plates provide protection to the full perimeter of the enclosure.
Transparent doors, vented doors, and 3-point locking doors are available as optional accessories. They can be easily fitted by simply removing the hinge pins of the original doors.
Rain hoods are an excellent choice for retrofitting onto electrical enclosures with a flat roof or for new applications when a sloped roof electrical enclosure is not feasible. Rain hoods are required to prevent settling and building up of liquids, corrosive solids, minerals, dust, dirt and debris on top of an electrical enclosure. If corrosive liquids and solids settle and build up on top of an electrical enclosure, the integrity of the electrical enclosure coating and material may be compromised which may lead to corrosion and ingress of liquids and solids into the enclosure. Without maintenance, this may compromise internal electrical components and could increase risk of electric shock. IP Enclosures rain hoods are easily fitted onto IP Enclosures electrical enclosures. All IP Enclosures electrical enclosures are manufactured with encapsulated nutserts to accommodate optional rain hoods without drilling. This ensures that the IP rating is maintained.
Solar panel brackets are also available and designed to fit the encapsulated nutserts that are provided on our electrical enclosures to enable ease of fitting of solar panels without drilling. The angle of the solar panel can be adjusted to allow for optimum solar panel performance.
We provide a range of adjustable shelf kits. Shelf systems have many uses and can be used for component storage, separation and battery storage. Fixed shelves are pressed to provide strength and are provided with rails and fasteners for ease of installation. Shelves for wall-mounted enclosures and floor standing electrical cabinets can be fitted without drilling to ensure ease of installation and to maintain the integrity of the IP rating. Multiple shelves can be fitted into each enclosure and shelves can be fully adjusted to the correct position.
Other accessories include replaceable gland plates in various materials, earthing kits, plan pockets, and LED lights to improve safety during access.
A range of accessories are also available to suit 19” rack cabinets.
Mounting
It is important to select the best location and orientation for your enclosure. Then select a suitable mounting method to suit the overall plant layout and design of the adjacent equipment. A range of mounting accessories are available including bases, pole-mounting kits, and standard wall-mounting brackets. It is important to provide safe access while maintaining adequate operator walkway access. In addition, if mounting the enclosure from an adjacent structure, it is important to ensure that the structure is adequately designed to withstand the additional loads.
Security
The very nature of an electrical enclosure is to provide protection of components being housed, while providing protection of people from electric shock. The essence of an enclosure therefore inherently includes security as a fundamental principle. For this reason, it is important to consider the enclosure construction and the locking system.
For standard industrial electrical installations, a standard electrical enclosure with standard locking may suffice. However, for installations in public spaces, it is important to prevent unauthorised access, vandalism, theft and cyber security threats. An upgraded locking system may suffice. However, to assist to mitigate this risk further, our field cabinet range incorporates recessed doors to reduce the risk of doors being levered open. The application will largely influence selection.
Locking mechanisms and hinges for doors should be of mechanical strength sufficient to withstand stresses in normal conditions and short circuit conditions. It is important to select locks to suit the enclosure and the application. For example, a standard lock may be suitable for a small control panel inside a manufacturing facility but a special locking system may be required to restrict public access to a large outdoor weatherproof cabinet. In addition, various utilities, facilities and applications have specified lock types or key types to conform to a site-wide standard for their electrical cabinets.
IP Enclosures provide standard locks with all electrical enclosures and can provide optional locking systems to suit any requirement including electronic and restricted key locking systems. Common options are key lockable swing handles, padlockable swing handles, key lockable wing knobs and padlockable wing knobs. Keyed options are available in several barrel combinations to enable customers and facility owners to change out barrels to suit their requirements. It is also important to consider the grade of material for locking systems and whether advanced interlock systems are required.
For 19” rack cabinets, security is a top concern. Measures need to be taken to safeguard data from cyber security threats as well as physical threats.
Electrical Safety
Before starting any work, please consider electrical enclosure safety and check with your local authority for regulatory requirements. Contractors shall engage a Licensed Electrical Contractor to perform duties and functions of Electrical Works. The electrical equipment and associated wiring within electrical enclosures and electrical cabinets shall comply with the relevant requirements of IEC 61439, AS/NZ 3000, AS/NZS 3100 and the Electrical Safety Act 2002 and associated Regulations and Codes of Practice.
This is a guide only. Refer to relevant standards, project requirements and technical specifications for specific requirements.