  Causal theory is now widely developed with many applications to medicine and
public health. However within the discipline of reliability, although causation
is a key concept in this field, there has been much less theoretical attention.
In this paper, we will demonstrate how some aspects of established causal
methodology can be translated via trees, and more specifically chain event
graphs, into domain of reliability theory to help the probability modeling of
failures. We further show how various domain specific concepts of causality
particular to reliability can be imported into more generic causal algebras and
so demonstrate how these disciplines can inform each other. This paper is
informed by a detailed analysis of maintenance records associated with a large
electrical distribution company. Causal hypotheses embedded within these
natural language texts are extracted and analyzed using the new graphical
framework we introduced here.
