How to select an electrical enclosures

Enclosure Selection

How to choose the best electrical enclosure to suit your need?

There are several factors to consider when choosing an electrical enclosure.

Step 1. Determine the IP Rating to suit the application
Step 2. Choose the material to suit the environment
Step 3. Select the size to suit internal components
Step 4. Add mounting and ventilation accessories

This selection guide provides information to help select electrical enclosures. Following this guide will help to optimise the life of enclosures and internal components.

IP Enclosures conform to IEC 62208 – Empty enclosures for low-voltage switchgear and controlgear assemblies.

Scope and Application

This selection guide applies to empty enclosures for low voltage switchgear and controlgear assemblies in accordance with AS62208 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, refer to our comments regarding electrical enclosures and AS61439 Low voltage switchgear and controlgear assemblies.

IP Ratings

The most important decision when choosing an electrical enclosure is to select what IP rating is needed. Ingress Protection IP Ratings are defined in IEC60529 (AS60529, EN60529) 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 can also be found in our electrical enclosure technical catalogue. If an outdoor or weatherproof electrical enclosure is required, it is important to select the correct enclosure with the required IP rating. Single door IP Enclosures electrical enclosures are IP66. Double door IP Enclosures electrical enclosures are IP55.

Materials

What material is best for electrical enclosures? 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 provide powder-coated galvanised steel for general industrial applications and grade 316 stainless steel for extreme duty applications that require high corrosion resistance. If the application has high levels of exposure to chemical or chemical cleaning, check for compatibility using the chemical resistance table in our catalogue. Refer to the chemical compatibility chart below for assistance with material selection. Care must be taken assessing tenders and quotes offering low quality imported enclosures manufactured using low quality non-conforming stainless steel from Chinese mills. We recommend only accepting stainless steel from high quality European mills. If in doubt, request a material test certificate from the enclosure supplier to determine country of origin of raw materials.

Sizes

How to size an electrical enclosure? 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, creepage, airflow and maintenance accessibility. When sizing enclosures, the distances between a conductive barrier or enclosure and the live parts they protect should not be less than the values specified for the clearances and creepage distances. Both steel electrical enclosures and stainless steel electrical enclosures range in size from 300H x 200W x 150D to 1200H x 1200W x 400D. For degrees of protection provided by enclosures against electromagnetic disturbances (EM Code), refer to IEC 61000-5-7.

Mounting

How do I mount an electrical enclosure? 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. This could be either wall mounting brackets, a stand, handrail mounting or pole-mounting. This is to provide safe access while maintaining adequate operator walkway access. In addition, if you are mounting the enclosure from an adjacent structure, it is also important to ensure the structure is adequately designed to withstand the additional loads.

Inner Doors, Escutcheons

How do I attach an inner door escutcheon plate? Hinged, removable inner door escutcheons are a standard option and can be easily fitted into each enclosure for mounting components. If you require inner door escutcheons, be sure to check the depth of the enclosure to ensure minimum distances between and around components are maintained. Enclosures up to 400mm deep are available to ensure large electrical equipment and drives can be safely housed behind escutcheons.

Security and Locking

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 what type of locks will be best for your enclosure. 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 standard for their electrical cabinets. IP Enclosures provide standard locks with all electrical enclosures and can provide optional locking systems and swing handles to suit any requirement. 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. It is also important to consider the grade of material for locking systems and whether other more advanced interlocking systems are required.

Air Conditioners, Ventilation and Rain Hoods

The application, environment, location and installation may require heat deflection, venting, cooling or heating. Enclosed assemblies for outdoor and indoor installations in high humidity and temperatures varying with wide limits should be provided with suitable ventilation, heating and drain holes while protecting degree of protection. We can help you select options that you may need. Options include ventilation fans, filters, vents and sun shields. Rain hoods and vent hoods are also available. Generally when ventilation is required, at least one filtered inlet vent is provided on the left or right side of enclosure approximately 300mm minimum distance from ground level; and at least one filtered outlet vent is provided on the left or right side of enclosure approximately 150mm maximum distance from the top. If fans are provided, they are generally installed adjacent to the inlet vent. When designing the layout of the internal contents of the enclosure, allow for minimum distances around vents, filters and fans for airflow and maintenance. Electrical enclosures can be provided customised to include cut-outs with ventilation accessories fitted. Enclosures conforming to IEC/EN/IEC 62208-are intended for use in the following ambient temperature conditions:
– Ambient air temperature for indoor locations: Air temperature does not exceed +40°C with average of +35°C over a 24 hour period. Lower limit is -5°C.
– Ambient temperature for outdoor locations: Air temperature does not exceed +40°C with average of +35°C over a 24 hour period. Lower limit is -25°C.

Electrical Safety

Can I install an electrical panel? 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 AS/NZ61439, 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.

For more help choosing the right electrical enclosure for your application, please feel free to contact us.

Chemical Compatibility Chart*

ChemicalCarbon Steel (Unpainted)316 Stainless SteelPolyurethane
Acetic AcidD-Severe EffectB-GoodD-Severe Effect
Acetic Acid 20%D-Severe EffectA-ExcellentD-Severe Effect
Acetic Acid 80%D-Severe EffectB-GoodD-Severe Effect
AcetoneB-GoodA-ExcellentD-Severe Effect
Alcohols: EthylB-GoodA-ExcellentD-Severe Effect
Aluminum ChlorideA-ExcellentB-GoodB-Good
Aluminum Chloride 20%A-ExcellentC1-FairA-Excellent
Aluminum SulfateD-Severe EffectB2-GoodB-Good
Ammonia 10%A-ExcellentA-ExcellentD-Severe Effect
Calcium CarbonateB-GoodB-GoodD-Severe Effect
Calcium HypochloriteD-Severe EffectB1-GoodD-Severe Effect
Carbonic AcidD-Severe EffectA-ExcellentA-Excellent
Chlorine (dry)B-GoodB-GoodD-Severe Effect
Citric AcidD-Severe EffectA2-ExcellentA-Excellent
DetergentsA-ExcellentA1-ExcellentB-Good
EthanolB-GoodA-ExcellentD-Severe Effect
Ferric ChlorideD-Severe EffectD-Severe EffectA-Excellent
Ferric SulfateD-Severe EffectA-ExcellentB-Good
Hydrochloric Acid 20%D-Severe EffectD-Severe EffectB-Good
Hydrochloric Acid 37%D-Severe EffectD-Severe EffectD-Severe Effect
Hydrogen Sulfide (dry)D-Severe EffectA-ExcellentA-Excellent
LubricantsA-ExcellentA2-ExcellentB-Good
Magnesium HydroxideA-ExcellentA1-ExcellentD-Severe Effect
Nitric Acid (5 to10%)D-Severe EffectA-ExcellentD-Severe Effect
PetroleumC-FairA1-ExcellentB-Good
Phosphoric Acid (<40%)D-Severe EffectC-FairD-Severe Effect
Salt Brine (NaCl saturated)D-Severe EffectA2-ExcellentD-Severe Effect
Sea WaterD-Severe EffectC-FairD-Severe Effect
Sodium BicarbonateC-FairA1-ExcellentA-Excellent
Sodium Hydroxide (20%)D-Severe EffectB2-GoodB-Good
Sodium Hypochlorite (<20%)D-Severe EffectC-FairD-Severe Effect
Sulfur DioxideD-Severe EffectA1-ExcellentD-Severe Effect
Sulfuric Acid (<10%)D-Severe EffectB-GoodD-Severe Effect
Water, Acid, MineD-Severe EffectB-GoodD-Severe Effect
Water, FreshD-Severe EffectA-ExcellentA-Excellent
Water, SaltD-Severe EffectB-GoodD-Severe Effect

*The information in this chart is a guide only. Actual environmental conditions may vary expected results. Refer to material supplier and chemical supplier to confirm suitability for your application.

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