What should an electrical hazard label look like?

NFPA 70E doesn’t offer a lot of guidance for what a label should look like.  They give us a description of the types of equipment which are to receive a label and a minimum amount of information that is required to be on the label.  Beyond that, there is no required layout.  However, with the help of ANSI Z535, we are able to further determine a proper layout.

We use “WARNING” up to 40 cal/cm^2 even though values less than this very likely could result in death or serious physical injury.  This 40 cal/cm^2 cutoff is standard industry practice (the reason is actually another discussion, some of which is covered here).  Everything greater than or equal to 40 cal/cm^2 is red “DANGER”.

However, we also only use “WARNING” up to 1000V, anything beyond that is red “DANGER”. The reason being, shock hazards are proportional to voltage.  4160V would supply 9x more current to cross your body vs 480V, 12470V would supply 26x more current vs 480V.

Once we’ve met and understand the requirements of national standards we focus on conveying pertinent information.  You can see examples of our labels below, click on each to view it larger.

Ever since arc flash evaluations have become a topic, warning of arc flash has become priority for most when designing electrical hazard labels.  However, shock is much more prevalent and more likely to kill.  For this reason we place the same amount of emphasis on both shock and flash.  We give each the same priority, same font size and same space on our labels.  Now a worker can easily identify both hazards from a safe distance.

Even though NFPA leaves us flexibility, every word, every font size, every color is thought out. We have spent more time on label layout and label application than we ever dreamed of. ANSI Z535 governs label layout, they help us choose WARNING vs DANGER. The safety word must be the biggest font on the label and the next biggest size can only be a specific portion of the safety word. The PPE is derived from NFPA 70E. Seemingly minor changes to the label might change the intent of the information being conveyed.

We also have a poster available which helps describe each section of a label:  https://www.70econsultants.com/Downloads/RozelLabelPosterv7.pdf

Another one of our posts helps describe how we determine where a label is placed on equipment, see here.  We also explain labeling transformers here:  https://www.70econsultants.com/should-transformers-be-labeled/  Quantity of labels are explained here:  https://www.70econsultants.com/how-many-labels-should-go-on-my-equipment/