How do you label arc-resistant switchgear?

Mar 8, 2018
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#1
Hi everyone,

How do you label arc-resistant switchgear? Table 130.7(C)(9) shows Cat 0 for operations with the doors closed, but if you've done an IE analysis, you're not supposed to use Table 130.7(C)(9). The IE analysis does not consider whether or not the switchgear is arc-resistant.

If you calculate an IE of 5 cal/cm², do you need Cat 2* or 5 cal/cm² rated PPE to operate a breaker or is Cat 0 adequate?

Please help.

I didn't find the right solution from the Internet.

Thank you.
 
#2
This depends on the company's approach. The risk assessment covered in NFPA 70E - 2018 does make provision for determining the incident arc flash energy (this is different from the available arc flash energy that the system can generate). Now if the equipment is internally arc classified (IEEE C37.20.7 or IEC 62241-200) AND used as per the manufacturer's recommendations (installation, maintenance, and operation) AND with the system's limitations (x-kA for y-ms), then no further arc rated PPE is required (theoretically). Some companies reduce the clothing to a Category 1 as a minimum for electrical work.