Fire resistance

Our WKE Rapid-Box range is designed for tunnel applications and meets key fire safety standards, in particular DIN 4102 part 12. The enclosures are precision engineered with temperature-resistant ceramic terminals and take uncut conductors of up to 50 mm² (Cu), with the junction made using a 2.5 mm² conductor or via a 3-pin or 5-pin CEE socket in the housing cover. The cable junctions and connection housings are certified according to EN 61439:2011, provide intrinsic fire resistance in the passage for 30 minutes and are rated to a minimum of IP66.

Yes. Our Lifeline WKE 2-6 range of fire-rated enclosures is designed with height-adjustable mounting rails that can be set in two different positions, providing space for installing single or double terminals as well as fuse holders. The terminal block sits on the mounting rail in the high position, while the low position is ideal for specific applications such as D0 (NEOZED) fuse mounting. The enclosures are attached by two external, pre-fitted lugs that rotate through 90 degrees, and the terminal block can be adapted on the base carrier in 45-degree steps by adjusting a central screw on a sliding bracket.

Look for glow wire testing carried out to the IEC 60695-2-11 series of specifications, which all Spelsberg enclosures undergo. The test applies a non-flaming heat source, such as a heated wire, to the specimen for 30 seconds, with tissue paper below it to check for dripping. To pass our glow wire testing, parts exposed to live components must not burn or glow when exposed to a wire heated to 960°C ±15°C, depending on the enclosure material. Any residual glow must extinguish within 30 seconds of the heat source being removed, and any falling parts must not ignite the tissue below.

We evaluate the durability of our plastic enclosures against excessive heat and fire using an indirect flame method known as the glow wire test, carried out in line with IEC standards. The sample is brought into contact with a hot filament for 30 seconds, with tissue paper positioned directly below it. Parts containing live components are exposed to 960°C ±15°C, cavity wall parts to 850°C ±15°C and all other components to 650°C ±15°C. The test is passed if the enclosure does not burn or glow, or if the glow extinguishes on its own within 30 seconds of the filament being removed, and if falling parts do not ignite the tissue paper.

Our Lifeline WKE 2-6 range combines intrinsic fire resistance with features designed to speed up installation. The boxes are made from high-performance polycarbonate that stays non-conductive in a fire, supporting systems that need to stay operational for 30, 60, 90 or even 120 minutes. The adjustable mounting rail can be set in two height positions for single or double terminals and fuse holders, with the lower position suiting D0 (NEOZED) fuses. The base carrier repositions in 45-degree steps using a single screw, the external fixing lugs are supplied pre-fitted and rotate through 90 degrees, and patented knock-out membranes give clean, quick cable entry.

Fire-resistant enclosures are tested using the UL 94 test, established by the U.S. Underwriters Laboratories, and the European DIN 4102 part 12 standard. UL 94 assesses the burning behaviour of plastics through horizontal and vertical burning tests that classify materials by their ability to resist and self-extinguish flames, while DIN 4102 part 12 covers the fire resistance of electrical installation systems as a whole. Our WKE range is made from durable thermoset plastic and can help keep the equipment inside operating for 30 to 90 minutes (E30-E90), which suits emergency lighting, smoke extractor systems and other vital safety components on escape and rescue routes.

EN45545 has been mandatory for fire protection on European rail vehicles for several years, and Spelsberg has worked with rail industry customers on compliant solutions since before the standard took effect. Its WKE junction box range is tested to EN60670, with standard enclosures continually developed to meet EN45545 requirements alongside bespoke, customer-specific fire-safety solutions.

Enclosure operating temperature depends on material: polystyrene and ABS are rated from -25°C to 40°C, polyester (GRP) withstands up to 60°C, and polycarbonate offers the widest range at -35°C to 80°C. Aluminium, mild steel and stainless steel enclosures perform similarly to polycarbonate, with a typical maximum of around 75°C.

Condensation in outdoor enclosures is prevented by maintaining the correct IP rating, fitting properly sealed cable glands, and adding a pressure-equalising vent to release temperature-driven pressure changes without letting moisture in. In environments with large day/night temperature swings, an anti-condensation heater controlled by a thermostat or hygrostat keeps internal surfaces above the dew point.