Safety takes top priority in public buildings; especially, when it comes to historic buildings with wooden constructions. The danger often lies in out-dated electrical installations. Thanks to the electrical refurbishment at the townhall in Dordrecht, in the Netherlands, the historic building is now protected against arc faults.
Visiting the townhall of Dordrecht is like a journey back in time. Today, many of the buildings are still the same, but what has changed is the operation of these buildings.
One example of that is the electrical installation, which today facilitates the operation of everything inside and around the townhall. Starting from the Wi-Fi in the council hall, the audio in the wedding hall through to the lighting of the six-century-old prison cells in the attic.
Despite its construction in 1383 the historic building has to comply with building regulations, the application standard NEN1010 (comparable to the German DIN VDE 0100 – 420) and other regulations in every respect. Those areas in which there are no regulations but recommendations, are given particular focus and a sympathetic eye to the building’s historic character is considered in their adoption.
For example, the detection of arc faults is not mandatory according to NEN1010 but recommended as a precautionary protective measure. Due to the completely wooden construction of the attic, protection against arc faults should not be considered as a superfluous luxury because more than 30 percent of all fires are caused by faults in the electrical installation. A part of the number of fires can be prevented thanks to the Arc fault detection device (AFDD).
Safety as top priority
The municipality attaches great importance to safety. That’s why proactive maintenance, including the few visible technologies in place remain at the top of the agenda. Inspections offer the possibility to check whether the relevant laws and regulations are complied with and identified that the enclosure in the attic needed to be condemned. Since the installation of the enclosure in 1985 there have been several technical developments and work was required to update the enclosure accordingly.
Wooden constructions require special attention
In the attic, heavy wooden beams define the floorplan of where the boiler house is located; and due to the narrow and complete wooden surroundings, special care is needed. That’s why the detection of arc faults, overloads and short-circuits is vital.
As an example, loose wires or cables could cause sparks or discharges released by touch. With the voltage difference the sparks could ignite the ionized gas between the conductors. The ionized gas cannot be detected by residual current circuit breakers or miniature circuit breakers so they will not break the circuit, which results in an electric arc fault. In the event of an electric arc lots of heat is released, which can then cause a fire. Specifically in surroundings completely made of wood, this represents a high risk.
Arc fault detection devices (AFDD)
In order to protect the historic surroundings against the consequences of arc faults, Gertenbach Elektro decided to cooperate with ABB to renovate the installation in the attic using the AFDD. “We’ve been cooperating with ABB for several years and are very pleased with the quality of their products and their expertise. The AFDD is a good example of such a high-quality ABB product.” An arc fault detection device (AFDD) with integrated miniature circuit breaker (MCB) can not only detect arc faults but also protects the electrical installations against overloads and short-circuits.
The AFDDs S-ARC1 und S-ARC1 M are available with breaking capacities of 6 kA and 10 kA. For the connection with cables or terminal blocks the AFDD is equipped with bi-directional cylinder-lift terminals. Maximum safety and service continuity is guaranteed thanks to continuous self-testing. By pushing the test button it is possible to check the correct functioning at any time. The AFDD portfolio has been extended by DS-ARC1, an AFDD with integrated RCBO (Residual Current Circuit Breaker with overcurrent protection) that can additionally detect earth fault currents.