I understand that category 0 causes confusion in the field and that is why standards don't use them anymore. However, for the existing warning labels, do we treat them as a big change and need to replace them with Category 1 labels immediately? There are so many 0 labels in most of the our projects.

You don't need to replace them. If you read it carefully, the minimum standard for clothing for electrical work is nonmelting clothing, which is sufficient up to 1.2 cal/cm^2. I said clothing, not PPE. Clothing is not PPE. PPE means something specific to regulatory agencies and among other things, employers must provide PPE unlike clothing. So "H/RC 0" disappeared for this reason. The practical impact is that nothing has changed except the wording. You have a choice. You can label panels as "no PPE required" or "<=1.2 cal/cm^2" and of course keep the H/RC 0 stickers around until they need to be replaced, but the intent is not to suddenly set 4 cal/cm^2 as a minimum standard.

Also now care should be taken not to have both PPE category and incident energy (cal/cm^2) together on the same label. We can either use Incident Energy Analysis Method or Arc Flash PPE Categories Method for arc flash risk assessment, but both should not appear on the same label, per NFPA 70E 2015 Article 130.5. If you use incident energy analysis method (IEEE 1584 or NFPA 70E Annex D.4) and determined Ei, then arc-rated clothing and PPE can be selected using Table H.3(b).

I agree that is what it states, but disagree in principle. In earlier editions we had 2 tables: a task table, and a PPE table. The task table decreased PPE requirements depending on the task. The PPE table gave minimum cal requirements for PPE depending on the combined hazard/risk rating. Mixing incident energy and the tables was technically invalid, but then so was the idea of PPE reduction to any value other than no PPE required because the hazard was not reduced and reduced PPE is the same as no PPE. The statement was made more clear but the task table has been broken up into a task table and an equipment table, fixing both issues. I see no technical limitation now to using the task table, but applying either incident energy and Annex, or the equipment and PPE tables. As the recent correction has harmonized the PPE table and the Annex, there is even less value in disallowing mixing because the PPE table and Annex are the same, except the 2 level is 8 cal/cm^2 and Annex allows the same PPE up to 12 cal/cm^2 if ATPV rating supports it. The final disassociation would be to replace PPE levels in the equipment table with cal/cm^2 values. That being said, the PPE 'level' has changed twice now in under 10 years (2* became 2 and “old 2“ was removed, H/RC becomes PPE level). If the labels are to have longevity, use cal/cm^2 and drop 'level'.

The focus should not be on the label, but electrical safety competency of your Qualified Electrical Worker on interpreting the information when they need to.

At this point I would recommend that your Electrical Safety Program manages the requirement of providing the right information to the QEW.

At this point I would prefer that we provide information to the QEW in results tables from the P.Eng. Stamped report or by the policy in your Electrical Safety Program.

To much time and money spent on "labelling" instead of developing and maintaining QEW electrical safety competency.