Posted 10 March 2014
What’s the difference between EIB, KNX & JH(st)H is a fair question.
Both KNX and the former EIB cable were derived from the German telephone cable JH(st)H so there is obvious similarity. Whilst described as two pair, JH(st)H and EIB Cable is normally laid up as star-quad configuration (four cores twisted tightly together). Certified KNX is a true two pair cable where the cores are twisted into pairs then the pairs twisted together to ensure better signal balancing.
Using a star-quad configuration reduces the cables outer diameter, this in turn means that fewer materials are used to produce it thereby reducing cost; the trade-off is a potentially lower performing cable. Sadly not everyone puts performance before saving money.
Another notable difference can be product quality. JH(st)H is so widely used in Europe it’s a price driven commodity resulting in many suppliers cutting corners where they can save a cent or two. Reducing the conductor diameter slightly, using thinner aluminium foils or using substandard plastic compounds are common cost savings. If you buy the product from a handful of different suppliers they are all likely to differ in quality resulting in possible performance differences across your installation. Using certified KNX removes that risk, the cable “recipe” and required data performance is very clearly documented by KNX and they independently test it as part of the certification process. Only certified KNX can carry the KNX logo as a mark of quality assurance.
On the occasions that we meet a price objection a quick product comparison normally shows that the customer is not comparing eggs with eggs. So, you have to ask if you are going to the expense of automating a building why compromise on the cable quality? The cable is likely to be the one of the lower cost components yet most critical. If it doesn’t work the building will not function either.
So why should you use certified KNX? It ensures quality, performance, system integrity, comfort & peace of mind.
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