Choosing an outdoor enclosure:
what to look for?

What is an outdoor enclosure?

An outdoor enclosure — also called an outdoor cabinet or external enclosure — is a weatherproof enclosure for permanent use in the open air, without protection from a building or roof. It reliably protects the installed electronics, controls and network components against rain, wind, UV radiation, snow, temperature fluctuations and unauthorised access.

The decisive difference from a standard electrical enclosure: an outdoor enclosure is designed for all weather conditions — from arctic cold to desert heat — and meets higher requirements for degree of protection, impact resistance and thermal management. ZPAS electrical enclosures for indoor use are available separately.

Degree of protection: IP54, IP55 or IP65 — what do I need?

The IP rating (Ingress Protection according to EN 60529) is the most important selection criterion for an outdoor enclosure. It describes the protection against foreign bodies (1st digit) and against water (2nd digit).

• IP54 – dust-protected, protected against splashing water according to EN 60529. Standard degree of protection of ZPAS outdoor cabinets (SZD series) — covers the typical outdoor applications: 5G, charging stations, power distribution, industry.
• IP55 – dust-protected, additionally protected against water jets from all directions. Available from ZPAS for the SZD series on request (higher degree of protection) – for particularly exposed sites.
• IP65 – dust-tight, protected against water jets. For locations with intensive water exposure (e.g. high-pressure cleaning) — this is the domain of stainless steel or wall-mounted enclosures, which ZPAS supplies as indoor enclosures, not for unprotected outdoor installation.

As a rule of thumb: IP54 covers typical outdoor applications, IP55 additionally covers particularly exposed sites. IP65 only becomes relevant where direct pressurised water jets or high-pressure cleaners are to be expected, i.e. in indoor washdown areas. You will find a complete explanation of all IP ratings in the IP table in the FAQ.

In addition to the degree of protection: IK10 (impact resistance according to EN 62262, 20 joules) is the highest class of mechanical protection — standard on ZPAS outdoor enclosures. Relevant wherever vandalism, proximity to vehicles or harsh industrial environments play a role.

Material: why aluminium for outdoor enclosures?

The predominant material for high-quality outdoor enclosures is anodised aluminium — and for good reason:

• Corrosion resistance: aluminium forms a natural oxide layer that protects against rust. Anodising reinforces this effect permanently — with no further treatment over the entire service life.
• Weight: aluminium is around 65 % lighter than steel — relevant for transport, mounting on masts or roofs and for maintenance work at hard-to-reach sites.
• Dimensional stability: aluminium does not warp, swell or distort with temperature fluctuations. This ensures permanently tight doors and seals, even at −40 to +70 °C.
• EMC: chromated aluminium surfaces provide electromagnetic shielding (EMC) — important for radio equipment, radar and sensitive electronics. Available on request.

ZPAS manufactures outdoor enclosures in the Alum series (SZD) from anodised aluminium. Sheet steel versions are available as an option — for example for cost reasons at well-protected sites with a short operating life. ZPAS does not manufacture plastic enclosures (GRP/polyester).

Thermal management: cooling and heating outdoors

Technology generates power loss — and it has to be dissipated without compromising the degree of protection. Outdoors, summer heat and frost come into play as additional factors. Depending on the application, ZPAS integrates various thermal management systems:

Cooling

• Positive-pressure ventilation with filter mats – for low power losses, IP54-compliant. Simple, inexpensive, low-maintenance.
• Air/air heat exchanger – cools the interior without letting outside air into the enclosure. The degree of protection is maintained. For medium power losses.
• Air/water heat exchanger – for high power losses when a cooling water line is available.
• Compressor air conditioner – for extreme heat loads and high ambient temperatures.
• AHP – Air Heat Pump – patented ZPAS development. One unit cools and heats the enclosure; its output is modulated instead of being switched on and off — which reduces energy demand compared with separate cooling and heating units. Particularly relevant for 5G base stations, charging infrastructure and smart grid applications.

Heating

• PTC heater (thermistor) – for frost protection at −40 °C. PTC heating elements are self-regulating: the warmer they get, the higher the resistance — overheating is impossible. Reliable, maintenance-free, durable.

Rule of thumb: for power losses up to approx. 50 W, natural convection is often sufficient. From 100–200 W, an air/air heat exchanger is advisable. From several hundred watts, active cooling (air conditioner or AHP) makes sense.

Dimensions and baying system: scale flexibly

ZPAS outdoor enclosures of the SZD series are available in standard widths from 409 to 1,654 mm and depths from 409 to 1,009 mm, with freely selectable height; special sizes are possible in every direction — even over 4 m wide and well over 2 m high. This allows project-specific adaptation without compromising on standardisation.

Particularly practical: the baying system. ZPAS outdoor cabinets can be bayed side by side. Projects can start with a single enclosure and simply be extended as space requirements grow — a second or third cabinet alongside, joined mechanically and visually into one row. No re-planning, no replacement.

For foundations there are plinths, stainless steel foundation frames and concrete foundations, and wall and pole brackets for small cabinets.

Standards and certifications

When buying, look for testing in accordance with standards — not just manufacturer's claims without a certificate:

• EN 60529 – IP degrees of protection. A tested degree of protection is not the same as a manufacturer's claim. ZPAS SZD enclosures are tested according to EN 60529.
• EN 62262 – IK impact resistance. IK10 = tested at 20 joules. Standard on ZPAS outdoor enclosures.
• IEC 62208 – empty enclosures for low-voltage switchgear and controlgear assemblies.
• IEC 60068 – environmental testing (temperature, humidity, vibration).
• Marine / offshore – SZD in a saltwater-resistant version.

All declarations of conformity and certificates are available in the ZPAS download area.

When is it worth buying an outdoor enclosure direct from the manufacturer?

Buying outdoor enclosures direct from the manufacturer gives you:

• Special sizes: project-specific dimensions in every direction, to drawing or specification.
• Integrated thermal management: cooling or heating is installed and matched directly at the factory. No additional work on site.
• A scalable baying system: enclosures can be extended at any time — the investment remains usable.
• Technical advice from specialists: IP rating, material, thermal management, standards — ZPAS advisers know the products down to the last detail.

Two typical applications show how these criteria come together in practice: outdoor enclosures for water management (pumping stations, sewage treatment plants — corrosion protection and heating are decisive) and outdoor enclosures for battery storage (BESS — temperature management and ventilation are decisive).