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Plug and play lighting connectors for the great outdoors

Installing electrical lighting equipment outdoors requires serious upfront consideration, as temperature changes, ultraviolet radiation, chemicals, high ozone values and the general wear, tear and ageing of materials can lead to water ingress and system failure. Combine these factors with the dangers of having live electrical connections in highly accessible spaces and the importance of using safe, secure, durable and reliable technology is obvious.

Material science

In many outdoor lighting systems, the seals in the vicinity of the connector faces and cable glands are particularly vulnerable. Exposed to the elements, they can shrink, with minute cracks beginning to appear, while the pressure in the sealed area drops. If this happens it is only a matter of time before water finds its way into the connectors.

This should come as little surprise, as in certain countries sealing points can be completely coated with water for weeks on end. Sometimes these factors are not considered in advance, with plug connections often put in trays that fill up with rainwater during a heavy downpour or just laid on the ground.

After rainfall, the small reservoir between the cable and the seal can fill with water, which remains there. Over time, capillary action causes the water to penetrate the casing, which is more likely when a connector is installed vertically. Water then repeatedly travels along the cable to the sealing point and during winter any water that has penetrated also freezes, thereby accelerating the ageing process. A further issue arises if a cable is faulty and water is able to penetrate it. In this situation, water will travel through the cable until it reaches the connector – something that can occur over great distances and be exacerbated in situations where cable is bent and under heavy mechanical stress.

Made to measure

There are a number of best practice installation measures that can be taken to reduce the impact of moisture penetration on outdoor lighting installations. These include avoiding cable contact with abrasive materials, using end caps and laying cable in such a way that any draining water is not routed to the cable gland. However, the best way to achieve a waterproof electrical connection is through the use of Wieland’s innovative RST range.

RST is a modular plug and play connection system that enables power distribution from a distribution board to final device, and can be supplied with pre-assembled cables. It was developed following the success of Wieland’s gesis indoor connection system. Installers recognised the timesaving and safe installation qualities of gesis and requested a solution that could provide the same benefits in outdoor environments.

LED lighting was a major driver for this development, as manufacturers realised that a connector system mounted on their outdoor luminaires could prevent damage to sensitive electronics while maintaining the waterproof integrity of their products. In addition to lighting, RST devices are commonly used in other outdoor applications such as motors, power distribution for 250/400V AC, power supply up to 50V DC, bus signalling and dimming, 24V supply, the AS-i communication protocol, and solar PV connections.

Safety first

Selection criteria should focus on a product’s ingress protection (IP) rating. This classifies the degree of protection provided against the intrusion of solid objects, dust, accidental contact and water. A product’s IP rating consists of the letters IP followed by two digits. The first digit indicates the level of protection that is provided against access to solid foreign objects, while the second digit denotes protection against the harmful ingress of water. The higher the number, the higher the protection offered.

The RST range is rated to IP65, IP66, IP67, IP68, and IP69. This means that the devices offer full protection against dust and other particulates, as well as protection against low and high-pressure jets and full immersion for up to two hours in 3m deep water.

Ingress of water through a faulty cable or other access points for moisture can be prevented from travelling through the inner cores of the cable and contact pins and thus into sensitive electronic devices by the use of internal lateral sealing barriers found in the RST waterstop options.

Four to the floor

 

Wieland’s RST range comprises four options that have been designed for a wide variety of uses:

  • RST CLASSIC

     

With a modular design and rated currents of 20A, 25A and 32A, the RST CLASSIC offers the perfect solution for any application. It features a comprehensive network of electrical connection technology components, all of which are pre-fabricated and tested in the Wieland factory. With 2-7-pole variants, the 6-pole and 7-pole connectors are optionally available as barrier seal models, which prevents any spread of moisture through the cable system. The connector housing is also designed in two parts to allow for easy assembly, saving valuable installation time.

  • RST POWER

 

RST POWER combines the most powerful connection capabilities with the highest possible degree of compactness. The connectors are available in 4-pole and 5-pole and are designed for 250/400V and a rated current of 50A. It can take cable ranges of up to 32mm diameter.

  • RST MINI

 

The RST MINI series boasts a compact design, allowing it to be a versatile option for a wide range of applications. The 2-5-pole plug connectors and device connectors are designed for up to 250/400V and 16A. Example part (144-3077)

  • RST MICRO

With rated values of up to 250/400V and 8A in a diameter of only 14.9mm, the RST MICRO is the smallest device in the RST range. Despite its compact design, the 2-pole and 3-pole connector is easy to assemble, consisting of just two individual parts which are connected to each other firmly and securely with just half a rotation. It also features an optional internal seal against water penetration and any moisture that collects inside is prevented from continuing along the contact pins and causing damage to the entire installation.

Spot the difference

The ATEX certified RST range takes waterproof and harsh environment electrical connection technology to the next level with a number of unique features.

According to BS EN 61535 automatic locking is required for mains connectors in a pluggable installation. Wieland’s Twistlock technology makes connectors interlock automatically on connection and there is an audible click when the assembly is complete. Unlocking follows the ‘bayonet’ principle through a slight rotation of the locking ring, while with the optional ‘safelock’ position, the connection can only be opened using a screwdriver – eliminating the possibility of unintentional disconnection.

Wieland’s RST range also reduces installation errors by using colour coding, so it is only possible to join connectors that match one another. The RST CLASSIC, for example, has nine colours and 20 codes, offering the highest number of options on the market.

Although RST connectors have been specifically developed for lighting technology they can be used for a host of other functions, particularly when space availability is limited. Due to the use of a standardised M20 thread, conventional cable screwed cable glands can easily be exchanged for more convenient pluggable connectors, enhancing the system’s flexibility. Wieland also offers computer aided design (CAD) files to designers so that the RST housing profile can be moulded directly into the endcap of a light fitting, for example.

See the light

Whether it’s required for a single connection or a more complex installation, the RST range is the go-to system for outdoor lighting projects where a waterproof, easy to configure solution is paramount. With just a few basic components including connectors, panel mount connectors, distribution units and cable assemblies, installations from the distribution panel up to each point of demand can be accomplished quickly and accurately. By using Wieland’s plug and play technology installers benefit from a timesaving of 70 per cent and 30 per cent lower financial costs when compared to a conventional system.

To find out more search Wieland RST at RS Components.

MD of Wieland Electric's UK subsidiary. Personally immersed in connection technology and industrial automation since 1991 - evangelist for plug+play wiring installations.

7 Nov 2019, 9:03