Arc Flash & Shock Hazard Warning Labels For Power Transformers

By Chris Dodds on 25th March, 2013

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I have noticed that at most facilities I have visited where an arc flash hazard analysis has been performed and arc and shock hazard warning labels have been applied to the equipment, warning labels have not been applied to power distribution transformers present on the site. Although transformers are not specifically called out in the list of equipment required to be labeled by NEC 110.16 nor in 70E 130.5(C), I do consider power distribution transformers as likely to require examination and testing while energized and therefore require warning labels to be applied. Additionally, where transformer enclosures provide access to energized cables and/or parts through several removable or hinged panels or or doors then each access panel or door shall be provided with a label. Work activities on power distribution transformers which may require access to energized cables or parts could include measuring for the absence of voltage to establish an electrically safe work condition for LOTO, diagnostic testing/measurement of primary or secondary voltages, and thermographic examination. Whether or not these labels are provided seems to be dependent on the entity performing the study and the requirements of the client. It is clear to me that unless the study specification requires labeling for power distribution transformers, then most likely labels will not be provided. I am interested to know of others experience with requirements for providing arc flash and shock hazard warning labels for power distribution transformers. Linked In Group Arc Flash & Shock PPE, Post by John Whitney.

Arc Flash Clothing, PPE & Protection

Arc flash can occur during live cable jointing, phasing in operations, racking in and out of switchgear, reclosing of electrical switchgear onto a fault, switchgear failure, excavating near live cables or accidental contact with live conductors during maintenance - arc flash hazards exist at both low voltage and high voltage.
 

Category:  Electrical Safety & Arc Flash

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