IEEE NESCIR548-2009 pdf download Introduction to the National Electrical Safety Code
Discussion: NESC Rule 013.B(3) states that:
Where conductors or equipment are added, altered, or replaced on anexisting structure, the structure or the facilities on the structure need notbe modified or replaced if the resulting installation will be in compliancewith either (a) the rules that were in effect at the time of the originalinstallation, or (b) the rules in effect in a subsequent edition of the NESCto which the installation has been previously brought into compliance, or(c) the rules of the current NESC edition. (Emphasis added).
Question (l): If a company proposes to add new “conductors or equipment”“on anexisting structure(.e, in this case the “existing structure” is a wooden utility companyelectric distribution and telecommunications pole), and if at that point in time the existingstructure and the existing facilities on the structure DO NOT meet ANY of therequirements in subsection (a) or (b) or (c) above, then must the entire existing structureand all of the existing facilities on that structure first be made compliant with theapplicable requirements of the NESC code BEFORE the proposed new “conductors orequipment”can be added to the structure?
Question (2): Does the response to this request for an interpretation depend on whetheror not the proposed new equipment or conductor can be installed, in and of itself, inaccordance with the requirements of subsection (a), (b), or (c) above even if thesurrounding structure is non-compliant?
Our utility believes that the text and meaning of Section 13(B)(3) are very clearconcerning Questions (1) and (2) above, but the utility is requesting confirmation of itsinterpretation from the NESC.
The answer to both questions is “Yes.’ As soon as a line/facility is found to be in noncompliance with the code, it is to be corrected according to Rules 214A4 and 214A5.Rule 214A4 requires defects discovered to be not in compliance with the rules that arenot immediately threatening to life or property to be recorded and scheduled forcorrection. Rule 214A5 requires defects which could endanger life or property to bepromptly repaired before any new work is done or new facilities are added. Rule 013B3also works in concert with Rule 230l, which requires maintaining clearances andspacings to meet the rules under the conditions specified in the applicable edition. Theterm “resulting installation is intentionally used in Rule 013B3 to cause a review of theentire installation at the time of work or inspection, not just the proposed addition.replacement or alteration.
If adding a new item, replacing an existing item, or rearranging existing items would not.in itself, either (1) create a structural, clearance, or grounding non-conformance; or (2worsen an existing nonconformance, then the addition, replacement or alteration can beperformed, but the other corrective work must be scheduled and accomplished underRules 214A4 and A5. Of course, if the noncompliance in the existing installation is ducto a structural limitation, then no additions may be made until this structural limitation iscorrected.