Interpretations

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

IEEE Standards Interpretations for IEEE Std C37.13™-2008 IEEE Standard for Low-Voltage AC Power Circuit Breakers Used in Enclosures

Copyright © 2009 by the Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue New York, New York 10016-5997 USA All Rights Reserved.

Interpretations are issued to explain and clarify the intent of a standard and do not constitute an alteration to the original standard. In addition, interpretations are not intended to supply consulting information. Permission is hereby granted to download and print one copy of this document. Individuals seeking permission to reproduce and/or distribute this document in its entirety or portions of this document must contact the IEEE Standards Department for the appropriate license. Use of the information contained in this document is at your own risk.

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November 2009

Interpretation Request #1
The IEEE Std C37.13-2008 edition includes 6.6, which reads: “6.6 Primary Disconnecting Devices:  Any replaceable or renewable component(s) of the primary disconnecting device assembly shall be located on the circuit breaker.” Is it to be understood that the intent of this requirement was to place the finger cluster on the circuit breaker so that it could be safely replaced in the field without opening the main disconnect for the applicable switchgear?  The text states, "Any replaceable or renewable component . . " and therefore it could be understood that if it was NOT replaceable, this requirement does not apply. Was the intent of the wording "Any replaceable or renewable component .." to allow the finger cluster to be either permanently mounted, i.e., not intended for field replacement and therefore does not need to be assembled to the breaker, the correct interpretation of the requirement?

Interpretation Response
The questions posed focused primarily on whether or not the primary disconnects must be mounted on the movable element. 

For explanation of the details provided in IEEE Std C37.13-2008, the following responses are provided: 

1) “…could it be understood that if it was NOT replaceable, this requirement does not apply? 

Answer: No. 

It is understood that the “it” refers to the primary disconnecting device assemblies. These primary disconnecting device assemblies are often called the “finger clusters.” IEEE Std C37.13-2008, 6.1 states that “the required functional components are listed in Table 1, and Table 1 bullet (12) lists “Primary disconnecting devices in accordance with 6.6”. Primary disconnecting devices (often called the “finger clusters”) are therefore required on the circuit breaker.

Subclause 6.6 states that “any replaceable or renewable component(s) of the primary disconnecting device assembly shall be located on the circuit breaker.” IEEE Std C37.13-2008 does not require that primary disconnects be built using replaceable or renewable components. However, if the components of the primary disconnecting device assembly are replaceable or renewable, these components shall be on the circuit breaker. 

2) “Was the intent of the wording “Any replaceable or renewable component …” to allow finger clusters to be either permanently mounted, i.e., not intended for field replacement and therefore does not to be assembled to the breaker, the correct interpretation of the requirement? 

This question is re-written to clarify what is understood to be the intended question. 

“Was the intent of the wording, “Any replaceable or renewable component …” to allow finger clusters to be either permanently mounted, i.e., not intended for field replacement and therefore does not to be assembled to the breaker, the correct interpretation of the requirement? 

Comment: The removed word “either” suggests that the author was going to ask if the primary disconnects could be either on the circuit breaker or in the switchgear. 

Answer: No

The answer is the same as is provided for item 1 above.