In the latest craze with “lean manufacturing”, a lot of businesses are rearranging their production lines and in a lot of cases, safety was not a serious consideration. We see a lot of emergency egress issues, serious electrical power constraints leading to improper power cord usage, fire extinguisher types and placement issues, etc. But the one item that seems to not find its way on the “Lean Manufacturing Checklist” is electrical clearances, and by this, I mean more than the traditional 36″ clearance in front of panels and disconnects. When installing machinery/equipment that will be anchored to the floor/structure, we not only should ensure we have proper working clearances in front of electrical panels, we should also consider the NFPA 70E Shock Protection Boundaries for when a worker needs to establish their safety zones when opening up a cabinet.
If your manufacturing equipment is positioned such that it is located in one or more of these Shock Protection Boundaries (e.g. Limited Approach and Restricted Approach) a production vs. maintenance battle will ultimately happen. But had the equipment been positioned just a little differently, we could possibly do both safely simultaneously.
Just consider these distances when laying out your manufacturing process by ensuring maintenance space is a consideration. We are seeing a lot of businesses relocating their machines/equipment and these distances are coming back to bite them in a big way. In almost all the cases we have seen, the machine/equipment could have been positioned such that the qualified electrical worker could do his/her job and not place the production worker at a risk for shock.
This tip may NOT apply to Arc Flash boundaries which may extend many feet from the face of the cabinet, but we should consider it.