What is an
electrical enclosure?

Definition: what is an electrical enclosure?

An electrical enclosure (control cabinet) is a closed metal enclosure for safely housing, distributing and controlling electrical and electronic components. It protects the installed equipment from external influences — dust, moisture, mechanical impacts — and at the same time protects people from direct contact with live parts.

At its core, an electrical enclosure is the heart of every electrical installation: this is where power is distributed, machines are controlled and processes are monitored. Whether in the factory hall, the substation, the wind turbine or the data centre — nothing works without an electrical enclosure.

Design: what is inside an electrical enclosure?

The mechanical design of an electrical enclosure follows a clear principle: the enclosure protects, the interior switches and controls. The most important components:

The enclosure

As standard made of galvanised sheet steel, powder-coated in RAL 7035 (light grey). For corrosive environments or cleanrooms, stainless steel (1.4301, AISI 304) is used. The enclosure dimensions depend on the contents: width, depth and height can be selected over wide ranges.

Mounting plate and DIN rails

Inside the electrical enclosure there is a mounting plate (galvanised, for direct mounting) and DIN rails (also: top-hat rails according to DIN EN 60715) for fixing modular devices. Cable ducts on the left and right keep the wiring neatly routed.

Electrical components

• Miniature circuit breakers (MCB) – protection against overload and short circuit
• Contactors and relays – switching motors and other loads
• Frequency inverters (VFD) – speed control for electric motors
• PLC / control units – automation and process control
• Terminal blocks – structured connection of cables
• Power supply (PSU) – supply for control components
• Busbars – power distribution at higher currents

Door, lock and seal

The door closes the electrical enclosure and, depending on the protection requirement, is fitted with a continuous silicone seal. As standard, the lock is a 3-point or 4-point espagnolette lock — also available with a cylinder lock or access control system for higher security requirements. ZPAS SZE3 enclosures open up to 150°, Z-SERVER racks up to 270°.

IP ratings: what do IP54, IP55 and IP65 mean?

The IP rating (Ingress Protection according to EN 60529) is one of the most important characteristics of an electrical enclosure. It describes how well the enclosure protects against foreign bodies (1st digit) and water (2nd digit).

• IP54 – dust-protected, protected against splashing water from all directions. Standard for industrial halls. ZPAS SZE2, PSL.
• IP55 – dust-protected, protected against water jets. For harsher industrial environments and roofed outdoor areas. ZPAS SZE3 (standard).
• IP65 – dust-tight, protected against water jets. For wet and washdown areas, clean rooms and the food industry. ZPAS SWN wall-mounted enclosures.

As a rule of thumb: IP54 for the hall, IP55 for harsher conditions, IP65 for wet and washdown areas; outdoors, outdoor enclosures with IP54/55. More detailed explanation of all IP ratings: → IP table in the FAQ.

Standards: which standards apply to electrical enclosures?

Electrical enclosures and assemblies are subject to clear standard requirements. The most important:

• IEC 62208 – empty enclosures for low-voltage switchgear and controlgear assemblies. Applies to the enclosure itself (basic mechanical and electrical requirements).
• IEC 61439 – low-voltage switchgear and controlgear assemblies. Applies to the fully equipped system — relevant for the panel builder.
• EN 60529 – degrees of protection provided by enclosures (IP code).
• UL certification – for use in North American markets (USA, Canada).

ZPAS electrical enclosures of the SZE2, SZE3 and SWN series are certified to IEC 62208 and UL. All certificates can be downloaded free of charge in the download area.

Materials: steel or stainless steel — which for what?

• Galvanised sheet steel – standard. Robust, cost-efficient, any RAL colour. For industrial halls, machine building and plant engineering.
• Stainless steel 1.4301 (AISI 304) – for the food industry, pharmaceuticals, cleanrooms and chemically aggressive environments. Corrosion-resistant, smooth surface, easy to clean. ZPAS SWN INOX series.
• Aluminium – main material for outdoor enclosures (ZPAS Alum series SZD). Light, corrosion-resistant, dimensionally stable from −40 to +70 °C. Not for standard electrical enclosures, but for open-air applications.

Panel building: enclosure vs. finished assembly

An electrical enclosure is initially an empty enclosure. Panel building refers to the entire process of populating and wiring: mounting the components on the DIN rail and mounting plate, wiring according to the circuit diagram, labelling and final functional testing.

This step is carried out either by the end customer, by a panel builder — or directly by ZPAS. The ZPAS custom engineering department in Nowa Ruda manufactures and wires electrical enclosures to the customer's specification: from CAD design and prototype through to the fully wired and tested assembly ready for series production.

→ More on panel building & wiring at ZPAS

When is an electrical enclosure from the manufacturer worthwhile?

Requesting electrical enclosures directly from the manufacturer gives you:

• Special sizes: width, depth and height freely selectable, to drawing or specification
• Special colours: any RAL colour possible, applied directly in our own powder coating plant
• Shorter supply chains: short distribution channels, direct communication with the factory
• Technical advice from specialists: degree of protection, material, standard — our advisers know the product down to the last screw