Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretation for IEEE Std 605™-2008 IEEE Guide for Bus Design in Air Insulated Substations

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October 2011

Interpretation Request #1
Bus End Conditions Relevant Clause: 12.1
When a pipe bus conductor passes through a bus support fitting, but is not welded to the fitting (i.e., a "slip fitting"), does IEEE Std 605-2008 consider this to be a pinned, non-moment resisting condition or a fixed, moment resisting condition?

Interpretation Response
IEEE Std 605-2008 defines a pinned end as free to rotate and fixed end is defined as not free to rotate. While we recognize that there is not a 100% true pinned or fixed, IEEE Std 605-2008 leaves it to the design engineer to determine whether to consider the end condition of the pinned or fixed.