IEEE NESCIR569-2012 en National Electrical Safety Code《国家电气安全规范》.pdf

1、 1 Copyright 2012 IEEE. All rights reserved. Interpretation Section 21. General requirements Rule 215C4b Grounding of circuits, supporting structures, and equipment - Non-current-carrying parts - Use of insulators in anchor guys (2012 Edition, pages 75-76) (2 October 2012) IR569 For dead-end and per

2、pendicular (not parallel) down guys, does Rule 215C4b in the 2012 edition require guy insulators to be installed to fall in between all circuits on that structure if the down guy breaks below the insulator? The 2012 revised version of this Rule states the condition of this requirement to be “. . .in

3、 the event that the anchor guy becomes slack.” Discussion: It is believed that Rule 215C4b in the 2012 edition DOES NOT require guy insulators to be installed to fall in between all circuits on that structure if the down guy breaks below the insulator on dead-end and perpendicular (not parallel) dow

4、n guys. The belief is that the guy insulator placement configuration examples shown in the attached Figure 1 through Figure 8 meet the intent of NESC Rule 215C4. However, at a recent 2012 NESC Changes seminar, it was presented that these are all violations (citing 215C4b) because no insulation is in

5、stalled to fall between the distribution primary and the secondary circuits. It is not believed that 215C4b is applicable to these installations because the Rule refers to the guy becoming slack, not broken. In none of these instances will a slacked guy become a conductive path between energized con

6、ductors or live parts of other circuits or equipment. It is the belief (interpretation) that the Figure 9 guy insulator placement configuration attached represents the intent of NESC Rule 215C4b and 215C4c. In this example, sagging guys can present a safety (and reliability) hazard if the guy insula

7、tors are not located properly. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 2 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 3 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 4 Copyright 2012 IEEE. All rights reserv

8、ed. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 5 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 6 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 7 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAF

9、ETY CODE INTERPRETATION 8 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 9 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 10 Copyright 2012 IEEE. All rights reserved. NATIONAL ELECTRICAL SAFETY CODE INTERPRETATION 11

10、 Copyright 2012 IEEE. All rights reserved. Interpretation The Interpretations Subcommittee has considered the subject Interpretation Request for Rule 215C4b and has developed a consensus report as follows: Rule 215C4b does not apply to specific design configurations, but applies to any design config

11、uration. The intent of this Rule is to limit the likelihood of voltage transfer between facilities due to a slack or broken anchor guy. Even though the Rule only uses the word slack to describe how voltage could be transferred, it also applies to broken guys since a broken guy is the ultimate in bei

12、ng slack. Note that the Rule is a performance rule, not specific to configuration (dead-end, perpendicular, parallel, etc.) or to clearance requirements. _ National Electrical Safety Code and NESC are both registered trademarks and service marks of the Institute of Electrical and Electronics Engineers, Inc. The NESC is available from the Institute of Electrical and Electronics Engineers, Inc., 445 Hoes Lane, Piscataway, NJ 08854, USA (http:/standards.ieee.org/)