Arc-flash hazard calculations in sectionalized switchgear/switchboards

[ish1284]

Hello,

I was wondering what your take is on arc flash hazard calculations for sectionalized, low voltage switchgear and switchboards which are not arc-resistant rated. My philosophy has always been to apply a label representing the worst case incident energy at the line side of the main circuit breaker to all sections of the gear.

Is it acceptable in your opinion to apply a separate label at the main (representing incident energy at the line side of the main), and then a separate label to the non-main sections (representing incident energy at the load side of the main) even if the gear is not arc-resistant rated?

If you're looking for an example equipment type/mfg. think Schneider PZ4 or QED-2.

Let's discuss.

 

[ron]

PZ4 is SWGR which have barriers between sections as is the nature of SWGR under its UL listing. QED2 is SWBD does not have barriers between sections as SWBD doesn't require it, allowing a failure in the first section to easily propagate across all sections.

I consider it a judgement issue.

I've applied a different label to the first Main section and different for the rest in SWGR applications and even a QED6 (has section dividers). But it is extra work, so it depends.

Same label for all in a regular SWBD like QED2