Uncompromising Safety – Electrical Installation at the University Hospital

Imtech GmbH & Co. KG was awarded the contract to work on the electrical installations in the central area of Building 23. This power and building technology company has more than 5,000 employees and constructs its own control cabinets at its facility in Illingen, Germany. The Imtech facilities in Frankfurt and Illingen collaborated closely on the University Hospital project. In all, 200 distribution boards were built, installed on site and connected to the hospital’s systems. Design and construction of the distribution boards occurred at Imtech’s Illingen manufacturing facility. The connection-ready distribution boards were delivered, installed and connected by the workers from Imtech’s Frankfurt office. In addition to the distribution boards that were installed in specialized utility rooms, nearly 80 ceiling-mounted distribution boxes were required for integration into the building’s suspended ceilings. These were also manufactured in Illingen, then installed and cabled on site.

Every device in the building is supplied with electrical power from these wiring distribution boards. In addition to general facilities, like administrative offices and doctors’ and nurses’ offices, these also include patient rooms, as well as operating rooms and treatment rooms. The latter areas include X-ray machines, lasers and other medical devices that need electricity. The ceiling-mounted distribution boards are equipped with WAGO’s 2002-3217 TOPJOB® S Through Terminal Blocks, which enable a change in conductor size from 4 mm² (12 AWG) to 2.5 mm² (14 AWG). With a conductor size of 2.5 mm² (14 AWG), the maximum permissible conductor length is only 25 m. Since the distances between the distribution boards and loads are often longer, the conductor size must be adjusted in the ceiling-mounted distribution boards. This highlights an important benefit: ease of wiring. Since the electricians must perform overhead cabling work while standing on scaffolding, rail-mount terminal blocks equipped with push-in connection technology are extremely advantageous.

Imtech also relies on this connection technology, found in WAGO’s TOPJOB® S Multilevel Installation Terminal Blocks, for the distribution boards. “The spring pressure connection technology in the installation terminal blocks saves a lot of time during assembly and guarantees durable, maintenance-free connections,” says Sebastian Löw, identifying the key advantage of the terminal blocks. As the project manager for switchgear construction in the Illingen branch, he was responsible for the project. All of the distribution boards’ outlets are equipped with RCD circuit breakers. And these are divided into two types. First there are conventional circuits that supply normal lighting or sockets. “In this case, there were an increasing number of outgoing circuits that were protected with RCD circuit breakers,” explains Matthias Renzig, the electrical site engineer who is managing the on-site wiring of the distribution boards. The outgoing circuits were created using WAGO’s 2003-7641 Multilevel Installation Terminal Blocks. An N-busbar links the N-disconnect slide links, which are protected using a common RCD circuit breaker.

Secondly, there are outgoing circuits to sensitive areas that had to be individually protected with an RCD circuit breaker for each circuit. A typical example of this would be the “bed head” wall power supply strips in the patient rooms. These bed strips supply the hospital beds with electricity, oxygen and compressed air. The call system and the data connections are also integrated into the bed strips. Patients’ medical devices can also be plugged into sockets that are integrated into the bed strips. The individual breakers on these circuits are intended to prevent a medical equipment failure if a defective device is connected to a neighboring socket. Under certain circumstances, triggering the RCD circuit breaker could have life-threatening consequences for the patient. Therefore, Imtech chose WAGO’s 2003-6641 Multilevel Installation Terminal Blocks with an internal N-disconnect to wire the distribution boards for these outgoing circuits. Even the conductors for these circuits have to satisfy specific requirements: They must be (N)YM-(St)J sheathed cables that can effectively shield their electromagnetic interference fields.