Diagnose the fault in a low voltage distribution box by checking for overheating, loose connections, and using voltage testers for safe troubleshooting. Always turn off the power before you start any inspection. Electrical contacts in LV switchgear must maintain low resistance to ensure efficient power transfer. Over time, oxidation, corrosion, and wear can increase contact resistance, leading to: Contact resistance testing is performed by applying a known current through the closed contacts and measuring. Installed in clean, well ventilated or air-conditioned locations, switchgear will require little routine maintenance. This. In addition to the general requirements of German public safety law (ProdSG), they also include the requirements set forth in the low voltage directive and, where applicable, the machinery directive.