Hello! Hope you are all doing great.

This is my first post from Argentina.

I work in an integrated steel mill and we have a quite big MV distribution network (around 3000 2 MVA transformers 13.8/0.4 kV) and some 132 kV substations 90 MVA each.

The MV switchgears range from GE and Westighouse from the 50´s and 70´s to some new Schneider Electric MC-Set Arc rated switchgears per IEC 62271-200 “High-voltage switchgear and controlgear - Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV.

Local codes nowadays are mostly aligned with IEC standards when referring to equipment construction. But when talking about Arc Flash, most people refer to NFPA 70E.

Because new equipment is Arc Rated, some people tend to believe that IEEE1584 Incident energy determination and NFPA 70E PPE selection are not necessary given that the IEC 62271-200 arc rated equipment should be resistant itself. ¿Is that so?

For sure considering the same short circuit power and protection settings a metal clad cabinet from the 50´s or 70's will perform differently than a modern arc rated switchgear, however I'm confused when mixing European and American standards.

Should specific PPE be worn anyway when operating an arc rated switchgear?

Best regards.

Martin.

It depends on whether the doors are open or closed. With doors closed, the objective is to contain the incident energy and redirect it away from the worker. However, if the doors are open for whatever reason, then the IEEE 1584 incident energy values would be used.

Hello Martin, I work at a large power plant, with several pieces of ABB's medium voltage arc resistant gear (SafeGear). I had spoken with ABB s couple years ago, and they had indicated it would only be arc resistant if the arcing fault current was less than a certain value (in our case 40 kA) and the arcing fault duration was less than 10 cycles. In a couple of locations, our available arcing fault current is higher than the gear's arc-resistant fault current level. As a result, I'd gotten the impression from ABB that the IEEE incident energy applied, and we have been labeling gear based on the IEEE incident energy and not treating it as arc resistant.

I'm not sure of the available fault current or duration at the equipment you are working with, but would be curious if the Schneider gear has the same fault current & duration limitation.