You need to begin by considering what the agency label means. It can best be compared to a hypot stamp. It indicates the product met a set of criteria at some point. In general it means that the product when shipped met some standard. It indicates what was, not what is.
If you go out into your office and pick a product with a label on it, it does not mean it meets todays standards. It does not mean that it still is in a condition that meets the standards that were applied when labeled. With this in mind, when a product is repaired, it is acceptable to leave the existing approval marks on the product. It is also acceptable to transfer the applicable marks to a replacement cover since the information conveyed is still valid. It is not acceptable to transfer a cover with its markings to a another product. It is acceptable to repair the product without removing or defacing the marks. They still convey a relevant message. If you knowingly degrade or otherwise make the marks no longer relevant it would be prudent to deface or remove them although I know of no agencies persuing this issue. If you rebuild or remanufacture the product, selling it with the original label would be misleading and would be a misuse of the mark not permitted by most agencies unless the facility doing the work was under an agency program. Selling a repaired product with the original label is acceptable. Obviously, there is a fine and wiggly line between repair and rebuild, but lets not get into that. Field application of any label can only be done under the conditions of the issuer of the label. For example in the case of UL, only UL staff under a special set of conditions and inspections will label a product in the field. A manufacturer only may label at his manufacturing location, and then only under the conditions established by UL. The existence of a label on a product after it has been installed is therefore less meaningful. If an explanation of the absence of the label is necessary for some reason, it might be reasonable to leave a note on or within the product explaining the circumstances. I would hope an inspector such as OSHA would not be irrational enough to insist a product be replaced if the product was safe but the label could not be maintained. You specifically mentioned power ratings. If the product is changed so the power ratings are different, you should be able to relabel those parameters and leave the remainder of the label as is, providing you have not done something detrimental to the safety of the product. Even replacing an entire power supply is a repair normally expected by most agencies and they do not make a fuss about the modification of labels. For this reason it is a good idea not to place product labels on replacable parts such as power supplies. The manufacturer cannot properly ship a replacement power supply with approval marks which apply to the entire product. If you should happen to face such a condition in the field, it would be appropriate to transfer the product label from the discarded power supply to the product (along with its approval marks). Alternatively you could make a replacement product label or request one from the manufacturer, which would necessarily come without agency marks. Bob Johnson
