NFPA 70E Section 130.5(C) is used to determine the likelihood of an arc flash occurrence which is required as part of the overall arc flash risk assessment. The risk assessment indicates if additional protective measures are required including the level of PPE to be used within the arc flash boundary.

NFPA 70E Table 130.5(C) has three columns:

• On the left side of the table is the description of the task.
• In the middle of the table is the condition of the equipment.
• On the right side of the table is the final decision on whether or not an arc flash is a likely occurrence.

Notice that the likelihood of an arc flash occurrence in this table is based on the overall condition of the equipment. Equipment must be examined to know whether it is considered normal or abnormal before the likelihood of an arc flash occurrence can be determined.

Equipment condition considered to be “normal” if all of the following circumstances apply:

(1) The equipment is properly installed in accordance with the manufacturer’s recommendations and applicable industry codes and standards.

(2) The equipment is properly maintained in accordance with the manufacturer’s recommendations and applicable industry codes and standards.

(3) The equipment is used in accordance with instructions included in the listing and labeling and in accordance with manufacturer’s instructions.

(4) Equipment doors are closed and secured.

(5) Equipment covers are in place and secured.

(6) There is no evidence of impending failure such as arcing, overheating, loose or bound equipment parts, visible damage, or deterioration.

Below is a sample of NFPA 70E. For the complete section, see the actual NFPA 70E text at NFPA.ORG. Once there, click on the free access link to NFPA 70E.

130.5 Arc Flash Risk Assessment.

(A) General. An arc flash risk assessment shall be performed:

(1) To identify arc flash hazards

(2) To estimate the likelihood of occurrence of injury or damage to health and the potential severity of injury or damage to health

(3) To determine if additional protective measures are required, including the use of PPE

(B) Estimate of Likelihood and Severity. The estimate of the likelihood of occurrence of injury or damage to health and the potential severity of injury or damage to health shall take into consideration the following:

(1) The design of the electrical equipment, including its overcurrent protective device and its operating time

(2) The electrical equipment operating condition and condition of maintenance

(C) Additional Protective Measures. If additional protective measures are required they shall be selected and implemented according to the hierarchy of risk control identified in 110.1(H). When the additional protective measures include the use of PPE, the following shall be determined:

(1) Appropriate safety-related work practices

(2) The arc flash boundary

(3) The PPE to be used within the arc flash boundary

Table 130.5(C) shall be permitted to be used to estimate the likelihood of occurrence of an arc flash event to determine if additional protective measures are required.