Electrical enclosure FAQs, answered by experts

UL (formerly Underwriters Laboratories) is a US-based safety consultancy that sets and administers standards across the full manufacturing process, from raw materials through to packaging. While UL approval carries particular weight in North America, its markings are recognised internationally.

The standards most relevant to enclosures include UL94 (flammability of plastic materials), UL746C (polymeric materials in electrical equipment), UL50 and UL50E (enclosures for electrical equipment, covering non-environmental and environmental considerations), and UL508 (industrial control equipment, now harmonised with IEC 60947 for new products, though existing UL508-approved products can remain accredited through continued testing).

UL-approved products display a UL mark, sometimes as regional variants like C-UL US or UL-EU, or an RU mark on components that can’t carry the full logo. Products from reputable manufacturers carrying these marks can generally be trusted, and buyers with concerns are within their rights to request testing documentation from the supplier.

Enclosures are tested against glow wire standards under the IEC 60695-2-11 series, which model what happens when overloaded connections or overheating components cause a fault.

Glow wire testing is an indirect-flame method: a heated wire is applied to a test sample for 30 seconds, with tissue paper positioned underneath to check for dripping. It measures how well a material resists ignition, whether it self-extinguishes, and whether it drips burning material.

To pass, load-bearing parts near live components must not burn or glow when exposed to a wire heated to roughly 960°C (tolerance depends on the material), any residual glow must go out within 30 seconds of the heat source being removed, and no falling debris should ignite the tissue paper below. This testing regime is what underpins confidence in an enclosure’s fire performance during a real fault condition.

Many enclosure ranges are designed with pre-punched or pre-drilled fixing points specifically to accommodate terminals, DIN rails, and cable glands, without compromising the enclosure’s ingress protection rating.

For standard applications, a product-finder tool can help identify an off-the-shelf enclosure that already suits the intended fittings. For more specific or complex requirements, CNC machining services allow any enclosure in the range to be modified to fit particular terminals, rails, or glands, with engineering support available for genuinely bespoke setups. Installation support — including wiring, assembly, and connection services — is also typically available to help meet project-specific or regulatory requirements.

Getting the IP rating right matters as much as the enclosure itself — under-protecting risks damage or unsafe conditions, while over-specifying adds unnecessary cost.

IP ratings come from the IEC 60529 standard and use two digits: the first covers protection against solids (from no protection up to fully dust-tight), and the second covers protection against liquids (from no protection up to resistance against powerful, high-temperature jets).

The right rating depends on the installation environment — how dusty the area is, how exposed to contact or traffic it will be, and whether it’s likely to face water droplets, splashes, jets, or full submersion. Indoor locations with normal humidity typically need only modest liquid protection, while outdoor or wash-down environments call for a much higher spec, paired with correctly rated cable glands to preserve the enclosure’s protection level once fitted.

Enclosures are independently tested and certified to confirm they meet their stated rating, including options built for long-term underwater use at depth.

Finally, remember that IP ratings say nothing about impact (IK rating), UV stability or temperature range — check those separately for outdoor and industrial installations.

Yes — enclosures designed for concrete construction applications can be made from polypropylene copolymer (PPC, plastic type 5 under the Resin Identification Code), a material that’s fully recyclable and can withstand multiple recycling cycles using either mechanical or chemical processing.

Beyond recyclability, PPC is lightweight relative to other plastics, which suits concrete applications, and is available across a range of ingress protection levels — from lower-rated junction boxes up to higher-rated universal installation housings — including protection Class II options for safe electrical separation where required. Manufacturing under an ISO 14001 environmental management accreditation supports an ongoing commitment to sustainability alongside product quality.

Outdoor enclosures need to resist UV exposure, temperature extremes, moisture, and physical impact all at once. Impact resistance specifically is measured by IK ratings under the EN/IEC 62262 standards, ranging from IK00 (no protection) up to IK10 (highest protection).

A rugged outdoor range should be built to operate across a wide temperature band (for example, roughly -35°C to 40°C), resist sunlight, wind, rain, corrosion, and chemicals, carry a high IP rating against dust and water, and reach a strong IK rating (IK09 is a good benchmark) for impact protection — covering the combination of weather and physical knocks an outdoor installation is likely to face.