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Wednesday, August 12, 2020
Question:
Hello CQD,
Could you please confirm if both a transformer and a busway feed connection tap can require working clearance defined by 110.26(A)? I typically provide clearance for those items but have found cases where it is inconvenient and would like the leeway to encroach if those elements are exempt. Some AHJ’s are accepting that those items are NOT LIKELY to “require examination, adjustment, servicing, or maintenance while energized” since readings for voltage (and current) can be taken at the line or load side panelboard and maintenance would typically be performed while de-energized within the guidelines of NFPA 70E (only allowing energized work in the few specific cases).
Thank you for continuing to provide this helpful and occasionally entertaining service,
Brett McClure
A
Answer:
Hi Brett,
Thanks for the question and the comments. It seems you answered your own question. In section 110.26 and the required working spaces apply to equipment that is likely to require examining, maintenance, adjustment, or servicing while energized, which is the determination that must be made. Transformers and busway tap connection enclosures appear to be in that category, but you should verify with the AHJ. Does a doorbell transformer require working space? Perhaps a dry type that is rated at 300 kVA would, if it is likely to require servicing or examination while energized, such as for thermography operations. Verify with the inspector.