Annex S is the last Annex in NFPA 70E. The title of Annex S is “Assessing the Condition of Maintenance.” There is additional risk associated with performing tasks on equipment that is not properly maintained. Therefore, it’s a fundamental safety step to assess how well equipment is maintained before performing any tasks on it. This Annex provides guidance.
Many of the comments that follow are not explicitly in Annex S, but are provided to help you put it into context.
First, assume the equipment has not been maintained at all. Then gather the information to build the evidence that it has been maintained. As you go about doing this information gathering, always use safe work practices [S.2]. Opening a hinged door or removing a bolted cover “…might expose workers to energized conductors or circuit parts inside the equipment.”
Start with a visual inspection to, among other things, verify the equipment “…is installed in a professional and skilled manner…” per the applicable “…industry codes and standards and the manufacturer’s instructions…” [S.3]. You can also look for signs of impending failure, such as arcing.
Annex S suggests that the workers who are trying to determine the condition of the equipment perform periodic tests and detailed inspections [S.4].
Permanently installed monitoring is another assessment tool. It “…can be performed using an uninterrupted method of data collection.” [S.5]. A big advantage is permanently installed monitoring systems “…often allow data collection without removing covers or opening doors and without exposing workers to electrical hazards.” This advantage should be capitalized on wherever practical when installing, upgrading, or replacing equipment. An example is adding an infrared camera window to the specs of the new switchgear you’re ordering. The return in saved labor costs alone can easily justify the investment.
Predictive techniques can alert you to identify a range of issues that are potential hazards if left unresolved. They can also alert you to urgent issues before things reach an alarm point [S.6].
Review the records (if any) of the periodic testing and inspections that are part of the maintenance function [S.7]. These can tell you much about not only whether the recommended maintenance was performed but also whether it was performed correctly. For example, if the records show before and after readings, the model and serial number of the test equipment used, and other professional level details you can be much more confident of proper maintenance than if just a bunch of boxes were checked. Another sign of professionalism is whether the CMMS is well-managed. If you’re an outsource resource for maintenance or upgrades, ask for a guided tour of the CMMS. Note that color coded labels (or similar) can be used to identify which equipment is in what condition.
See if they are using any industry standards or other references related to maintenance. S.8 specifically mentions NFPA 70B, Standard for Electrical Equipment Maintenance.
