Types of Electrical Enclosures — Welded, Modular & Semi-Modular Explained

A comprehensive breakdown of all enclosure types — construction methods, material choices, typical IP ratings and when to choose each type for your specific project requirements.

Welded Enclosures

Welded enclosures are fabricated from sheet metal and permanently joined at the seams, giving a single rigid, sealed structure. This construction is the standard choice for harsh industrial environments, outdoor installations and applications where vibration, dust ingress or moisture are a real concern — welded seams typically achieve higher and more consistent IP ratings than bolted or riveted joints. They're custom-sized to the application, from small junction boxes to large floor-standing panels.

Modular Enclosures

Modular enclosures are built from standardised panel sections that bolt together, allowing width, height and depth to be configured — and later expanded — without a full redesign. This flexibility makes them a popular choice for panel builders, machine manufacturers and data infrastructure projects where requirements evolve over the life of the installation, or where multiple similar panels need to be assembled quickly from common parts.

Semi-Modular Enclosures

Semi-modular designs sit between the two — a welded or otherwise fixed outer shell paired with modular internal fittings such as gland plates, mounting rails and partitions. This gives the sealing performance closer to a fully welded enclosure while still allowing the inside layout to be adapted for different equipment without ordering an entirely new enclosure.

Choosing a Material

• MS (Mild Steel) / CRS / HRS — cost-effective and strong, typically powder-coated for corrosion resistance; a common default for indoor and general industrial use.
• Stainless Steel (SS304 / SS316) — used where corrosion resistance matters most — coastal sites, food and pharma plants, chemical exposure — with SS316 offering better resistance to chlorides than SS304.
• Aluminium — lightweight with good natural corrosion resistance, often used where weight is a constraint, such as on mobile or overhead installations.
• GRP / FRP (Glass/Fibre Reinforced Plastic) — non-conductive and highly resistant to chemicals and corrosion, well suited to aggressive chemical or coastal environments where metal enclosures would corrode over time.

Matching Enclosure Type to IP Rating

Construction method and material both influence the achievable IP rating, but neither guarantees it on their own — gasket quality, gland selection and door sealing all matter just as much as the shell itself. See our complete guide to IP ratings for how to match a rating to your actual site conditions before finalising an enclosure specification.