NFPA 70E 130.7(C)(15)(a) Arc-Flash Hazard PPE Categories for Alternating Current (ac) Systems. Exercise 1.

Table 130.7(C)(15)(a) Arc-Flash PPE Categories for Alternating Current (ac) Systems.
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Table 130.7(C)(15)(a) Arc-Flash PPE Categories for Alternating Current (ac) Systems.

NFPA 70E Section 130.5(F) allows two options for selecting the proper level of PPE:

(1) The incident energy analysis method in accordance with 130.5(G)

(2) The arc flash PPE category method in accordance with 130.7(C)(15)

Either, but not both, methods may be used on the same piece of equipment. The results of an incident energy analysis to specify an arc flash PPE category in Table 130.7(C)(15)(c) is not permitted.

As mentioned above, 130.7(C)(15) can be used instead of performing an incident energy analysis. When choosing this option, Table 130.7(C)(15)(a) or (b) is used to determine the arc-flash PPE category and the arc-flash boundary. (See image)

In order to even begin to use this table, the qualified person must already know several key pieces of information:

If any one of the above are unknown, then Table 130.7(C)(15)(a) or (b) cannot be used, and an incident energy analysis must be performed instead of using the Table.

 

NFPA 70E Table 130.7(C)(15)(a) Arc-Flash Hazard PPE Categories for Alternating Current (ac) Systems

Equipment

Arc Flash PPE Category

Arc-Flash Boundary

Panelboards or other equipment rated 240 V and below

Parameters: Maximum of 25 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; working distance 455 mm (18 in.)

1

485 mm

(19 inches)

Panelboards or other equipment rated >240 V and up to 600 V

Parameters: Maximum of 25 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; working distance 455 mm (18 in.)

2

900 mm

(3 feet)

600-V class motor control centers (MCCs)

Parameters: Maximum of 65 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; working distance 455 mm (18 in.)

2  

1.5 m

(5 feet)

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NFPA 70E 130.7(C)(15)(a) Arc-Flash Hazard PPE Categories for Alternating Current (ac) Systems. Exercise 1.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Which of the following is true when determining the PPE category and arc-flash boundary from NFPA 70E?

A: Working distance does NOT need to be known in order to use Table 130.7(C)(15)(a).
B: The maximum short circuit current available does NOT need to be known in order to use Table 130.7(C)(15)(a).
C: Equipment voltage does NOT need to be known in order to use Table 130.7(C)(15)(a).
D: If any one of the values in the left-hand column of Table 130.7(C)(15)(a) are unknown, then Table 130.7(C)(15)(a) cannot be used and an incident energy analysis must be performed instead of using the Table.
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