Development and maintenance of a case-base is known to be one of the most difficult problems in real-world application of case-based diagnosis systems. The complexity of large technical applications result in large numbers of possible inter-and intra-system failures. Development of fault diagnosis systems for a rolling stock application and a battery emergency backup system showed that a base of fault cases is insufficient to accurately diagnose failures. The context of where and how problems occur should also be considered, such as the configuration and operational conditions of the application. This paper presents a model for the representation of this context for technical applications. The context information is applied for the representation, retrieval and retainment of cases.