Cable junction box enclosure delivers fire protection for tunnels

Industrial enclosure specialist Spelsberg has released a new version of its fire protection enclosures for use in tunnels and similar environments.

The WKE 6 T cable connection and junction box has been designed to withstand forces specific to tunnel environments. “Like other enclosures in Spelsberg’s WKE Lifeline range, they also ensure functional integrity for up to 90 minutes in the event of a fire,” confirms the company. The enclosures can connect cables with up to 16mm² cross sections.

Functional integrity in event of fire

The new WKE 6 T cable junction box meets standards E30 to E90 that ensure functional integrity is sustained in a fire from 30 to 90 minutes. The enclosure is intended for tunnel applications and can withstand high tunnel suction and pressure forces, adds Spelsberg. “It’s also well suited to use in buildings to ensure the reliability of emergency systems in the event of a fire. This includes maintaining the operation of alarms, emergency lighting, smoke and heat extraction systems, and fire extinguishers.”

The halogen-free enclosure is constructed from special thermoplastic that provides flame and heat retardance. Inside, the terminals are made from a high-temperature-resistant special ceramic that helps protect wiring and components. Protection is also provided by an IP66 rating, which ensures that the enclosure is both dust tight and can withstand high pressure water jets. The box is also IK08 impact resistant, one of the highest ratings of industrial durability.

The new WKE 6 T enclosure, finished in the WKE range’s distinctive orange colour to signify its fire-retardant capabilities, comes in four variants. Available as five-pole connection boxes or three, four or five pole junction boxes, the enclosures can accommodate cables from 1.5mm² up to 16mm² widths. Externally, all four variants measure 200mm x 250mm x 120mm.

Flexible assembly features

“The boxes are easy to install and are available with flexible assembly features typical to the Spelsberg range of enclosures,” states the company. “The terminal bracket can be positioned in 90° steps, and quick installation is thanks to an external stainless steel fixing lug.” Flexible cabling is achieved with three optional knock-out membranes per side, 12 in total. The box is also supplied with accessories, such as cable glands and seals – including seals for accidentally opened push-out membranes.

The enclosure is certified to the commonly required EN 60670 and IEC 62208 standards, and is also UL-EU and VDE certified. WKE 6 T provides Protection Class II and is rated up to 450 V AC.

Says Chris Lloyd, managing director, Spelsberg UK: “Regulations on fire protection in tunnels and buildings is very stringent, both in the UK and EU. Enclosures have to match the standards for the environment achieved by the rest of the durable electrical infrastructure, meaning that the design has to be extremely resilient to a variety of heat, flame, pressure and suction conditions. The new WKE 6 T enclosures are designed specifically to protect vital safety systems under fire and high suction, and are designed to ensure safe and controlled management of emergency situations.”