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Spelsberg’s WKE fire-resistant enclosures maintain electrical system safety

11 December 2020

SPELSBERG’S NEW fire protection enclosure improves the safety of electrical systems, enabling the control of fire alarms, evacuation systems and fire extinguishers for a minimum of 90 minutes in the event of a blaze.

The polycarbonate enclosures protect electrical connections, junctions and distribution to maintain the operation of building fire safety systems. Part of the Lifeline range of products, the upgraded WKE enclosures meet E30 to E90, the strict standards which ensure that functional integrity is sustained for a minimum of 30, 60 and 90 minutes in the event of fire. This means that Lifeline enclosures ensure the continued operation of alarms, emergency lighting, acoustic systems and evacuation-able elevators, which is typically required for 30 minutes.

Smoke and heat extraction systems, water-based extinguisher systems as well as Fire Brigade lifts can also continue to operate for a minimum of 90 minutes as a result of the protection provided by the WKE enclosures.

To achieve this level of fire resistance, traditionally electrical conduits have been encased in concrete. However, a specific limitation of this technique is the lack of flexibility in a situation where the design of the encasement and wiring architecture is required before the building is erected. From a safety perspective, while concrete encasement protects from fire, it doesn’t prevent electrical circuit failure.

While retaining the flexible installation advantages of externally mounted enclosures, the new additions to the Lifeline range are constructed from thermoplastic polycarbonate, which has been selected for its high heat tolerance. As polycarbonate is non-conductive during a fire, it also removes the risk of short circuits.

Internally, the construction includes terminal block clamps made from high temperature-resistant ceramic. To protect the enclosures from unauthorised access, sealing is achieved through integrated openings.

BS 7671 requirements

Lifeline meets the requirements of BS 7671 for electrical safety, as well as the German electrical circuit fire safety standard DIN 4102-12.

The strength and durability of polycarbonate also means that the new Lifeline enclosures have a high resistance to impact, duly meeting the IK08 requirements, as well as a high degree of protection against ingress including strong water jets (meeting IP66). Lifeline can be mounted in an outside environment and is certified in accordance with VDE and ULEU, as well as EN 60670 and IEC 62208.

The flexibility of the Lifeline enclosure means that it can also be installed when and where required without the need for significant prior planning of cable architecture and protection. Easily mounted on a fire-resistant wall or ceiling, the enclosure is attached by two external pre-fitted lugs which can be rotated around 90 degrees. The terminal block may be flexibly adjusted on the base carrier through three positions – 0, 45 and 90 degrees – thanks to a single, central screw and sliding bracket.

Lifeline enclosures are pre-assembled. Only wiring is required. For easier wire routing and attachment, the terminal block can be set on the mounting rail in the high position. Alternatively, the mounting rail can be set in a second low position, which is ideal for specific applications such as D0 fuse mounting.

The design also provides space for installing single and double terminals as well as fuse holders. Meanwhile, the enclosure cover can be kept safe during wiring with the optional cover-retaining strap. Pre-punched, patented knock-out membranes on the enclosure housing enable simple and clean cable routing and installation. The exterior of the housing provides labelling fields where lettering can be applied with adhesive strips or waterproof pen.

The Lifeline enclosures are available in formats for connecting and junction, secured junction with fuse included and for communication lines. Sizes range from 100 x 100 x 70 mm up to 250 x 200 x 120 mm. Project planning is offered for safety systems, while Spelsberg can also provide in-house expertise to ensure correct and rapid fitting for more complex projects.