Planning for intelligent building technology

This is a guide only.

If you have any questions or doubt at any point of the installations, please ask for our assistance from our Support team. We strongly advice that you seek the advice of a qualified electrician before carrying out any work on your wiring. HDL products uses both 230v mains voltage and 24v low voltage. Damaged components can occur if this is not observed.

Wiring a HDL bus system

HDL bus system consists of modules connected to each other. Each module has its own processor, which is programmed for a specific function and exchange of information with other modules connected to the bus. A bus power supply is required for bus communications.

Bus cable consists of two parts, one for the extra low voltage side 24v and the other part allow the communications between them.

This means that all your lights should be individually cabled directly to your electrical panel; For load switching/dimming you will have to use appropriately rated power cables, i.e. 1.5mm, 2.5mm, Twin & Earth etc.

Max length of bus cable is 1200 meters, but multiple subnets can be connected together so there really is no practical limit on the number of devices.

Wiring FAQ

Does my building need to be wired up differently in order to benefit from a HDL system?
You may ask, does the wiring in my house need to be different or special? The short answer is yes, and this mainly applies to the wiring to your light fixtures and the light-switches. The way in which they are wired is actually simpler than “traditional” wiring, so this can be picked up quite easily by any competent electrician, or performed with ease by one of our approved electricians or installers. Unless you already have this wiring in place (highly unlikely for most existing buildings), you need to install this wiring at build or renovation, unless you are willing to redecorate.

Such a method of wiring is not unique to HDL so therefore does not limit technology that can be used in. In fact, currently, 75% of all new or commercial buildings in Germany are being wired in this fashion, and home-systems are based increasingly on technology from the commercial sector.

In the UK, we run training courses for electricians every month in how to wire for “smart-buildings”, and we hope wire this way too!
What’s wrong with wiring my house the “conventional” way?
If you want to make your building smart, old-fashioned “conventional” wiring has many disadvantages and limitations due to there being multiple lights in different rooms on single circuits. Simply put, wiring your building the “old” way means that there is no practical method of controlling one group of lights without physically operating each light switch.

Smart-buildings are all about control, security, energy saving and convenience. Therefore anything less than being able to control each channel of lighting independently would make it a “dumb” building.
Aren’t there systems on the market that allow me to keep my existing wiring?
It is correct that there are systems on the market that claim to be compatible with “traditional wiring”, however these are more costly because they need to be small and fit into tight-spaces, and rely on wireless communication.

If you have the opportunity to perform a re-wire then we would always suggest wiring in the “smart” way, as wired communication and proper heat dissipation will lead to a more cost-effective and easily maintainable system.

If you are not able to wire in the “smart” way, then you may be interested to know that HDL will shortly be introducting a “retrofit range”, which will allow you to take advantage of your existing wiring. Further details will emerge in the later part of 2014.
How is a system for HDL wired?
Disclaimer: Please note that electrical work should always be carried out by a certified individual, and the advice given below is guidance only. Final wiring design should be performed out by a HDL approved installer/electrician.

HDL wiring requires each lighting circuit to be wired back to one “central panel” in the building. The central panel contains various lighting dimmers and other modules that have been carefully selected for your project, from our catalogue of over 200 products. If the property is large, the system can be “decentralised” into two or more interlinked panels.

The modules in the panels are connected together via a BUS cable. This BUS cable also connects devices that are installed in other locations, such as multi-function switches, multi-function sensors and heating controllers.

Wiring for HDL also concerns automated blinds/curtains, controllable power-outlets, 5A (lamp) sockets, motorised windows, motorised garage-doors, motorised gates, motorised locks, bathroom extractor fans, privacy glass, underfloor-heating and thermostats, and AC/fancoil/ducted airflow systems.

Please consult with an approved HDL installer before undertaking BUS wiring for HDL.

If you want to install a HDL system and are in any doubt whatsoever please contact us so that we may provide guidance to your electrician.
What about two-way or three-way switching?
The beautiful thing about HDL is that you do not need to think about the complexities of wiring for two-way or three-way switching. The wiring does not change just because you want to operate a light from various other switches.

With HDL, two-way, three-way, four-way or even ten-way switching is only a matter of programming afterwards, meaning that you can easily control your front-door porch or your children’s bedroom light from the switch next to your bed.
How do I go about making sure that my property is correctly wired for a HDL system?
We highly recommend using an HDL approved installer and by contacting us we can put you in touch with one local to you. We have hundreds of installers from around the UK and Ireland on our books, and each and every one of them is required to undergo and pass our rigorous training courses, which last several days and cover everything from installation & design, programming and even customer service. Running such a scheme, and monitoring our installers, ensures that the quality and service level of every HDL install is kept at the highest standards.

However, if you would like your own electrician to install the system and they do not have experience with HDL then you will be happy to know that our training courses are electrician-friendly. Our courses will provide the skills and competence necessary to any electrician who is willing to learn new skills, and can use a computer at a basic level.


When you are looking to buy KNX cable, look for the KNX logo. All KNX certified equipment has been tested and certified to meet this high standard and only equipment meeting this can carry the logo. This ensures the quality, reliability and guaranteed compatibility of all KNX devices and equipment.

The KNX cable also known as TP2 cable features two twisted pairs of solid conductor with a foil screen and tinned copper drain wire in a green LSHF jacket. It has been tested and certified as being suitable for use in KNX systems and bears the KNX logo.

For internal installations where the cable may be seen, the white KNX cable is ideal. The cable is exactly the same in construction as the standard green 2 pair cable but has a white LSHF sheath with yellow printing.

   Conductor Solid bare copper wire
   Insulation Polyvinylchloride (PVC)
   No. Of Cores 4 cores (two twisted pairs)
   Colour Code Red, Yellow, White, Black
   Drain Wire Solid bare copper wire
   Screen Aluminium over the yellow and white
   Outer Jacket (PVC) Green or White

Connecting the wall panels

There are different types of wall panels, but all back boxes are the same, each back box require 47mm uk style 35mm as a min. These back panels also have paint cover plates. The face plates are the click into place for a very quick installations. the bus cable is strip back to 5mm and inserted into a push fit connector.

Heating Control


The most typical use of HDL for heating control is via the use of our DLP panels. Each DLP panel has an inbuilt heating program which can be used with underfloor heating, underfloor cooling, radiator heating, and even electric heating.

The DLP has an inbuilt temperature sensor which it can use, optionally in conjunction with in-floor probes or other DLP panel temperature readings, in order to regulate the temperature in that zone. Temperature control is typically achieved by connecting a relay module to valve actuators on the heating manifold. The DLP uses PID control to regulate the temperature, which is the industry standard for intelligent thermostatic control, and ensures an even temperature even when the heating speed is slow (most water-based underfloor systems).

For most projects, however, we recommend taking advantage of the HDL Heating Controller. This device runs 6 independent thermostatic programs and features 6 inbuilt relays for connection to valve actuators. We recommend installing this device at the manifold itself.

Installation & Specification

There are many different types of heating systems, and HDL Heating Control is primarily designed to regulate the temperature. The control of the actual boiler is always done by the qualified heating engineer or electrician, and the HDL system provides the necessary signals (dry contact, or 240v live signal) where required to provide a “heat demand”.

Many modern systems with zoned heat often benefit from more than one pump in the property. If there is more than one pump, then further consideration should be given to the design. Please consult with your heating engineer.

We recommend following our wiring guidelines which can be obtained by contacting us.


When using HDL Heating Controllers, it is important to remember to set each one to use its own “Internal Clock”, and to set only one of them to “broadcast time”. It is also important to remember to set the daylight saving time in accordance with the recommendations shown in the software. If you have a logic module in the system, then please make sure that “broadcast time” is switched OFF in the Logic Module, as only one device in the system should be broadcasting the time. Using the above setting ensures that the heating modes (NORMAL, DAY, NIGHT, TIMER & AWAY) work properly.

Further Consideration

We will be adding further information to this website all the time. It is worth bearing in mind that consideration needs to be given to the following:

   Positioning of DIN Rail Panels
   Controlling different Lighting Loads
   Choosing the correct power supply size
   Consideration for Blinds and Curtains
   Underfloor Probes & Temperature Sensors
   Selection of Smart Sensors
   Third party devices and security systems

If you have any further questions or to discuss your project in detail, please contact us.

Copyright © 2019 All rights reserved.