Arc Flash

Arc Flash from Prosafe Inc

By: Prosafe Inc  02-02-2011
Keywords: Compliance, Safety System Design

ProSafe Inc. provides the following engineering services for Arc Flash Hazard Analysis:

  • - Calculation for incident energy and arc flash distances;
  • - Single line diagram modeling the power system;
  • - A list of the required Personal Protection Equipment and labels for each source location;
  • - Resources for data collection and placing labels.

Note: ProSafe Inc. only uses qualified, licensed electrical contractors when collecting data and placing labels.

With the recent introduction of CSA Z462 Workplace Electrical Safety standard workplaces are required, by the standard, to provide a practical safe working area for workers exposed to electrical hazards.

The standard applies to Canadian workplaces, contract job sites, and contractors working in Canada. It is mentioned that users of the standard should always refer to provincial and federal safety regulations that have jurisdiction over their work facility, contract job site, or profession.

The legal requirement driving the need for Arc Flash Protection is indicated in the Canadian Electrical Code Part 1 and Shock Hazards Rule 2-306 Shock and Flash Protection. In addition, there is an employer's overriding duty to their workers to protect their health and safety under the General Duty Clause found in the Occupational Health & Safety Act of every Province and Territory in Canada.

As with any new standard there are questions on application and the requirements needed to comply with the standard. The most prevalent element from the standard is the need for an Arc Flash Study.

  • - What is it?
  • - How is it completed?
  • - What is the cost?

The standard is divided into three main clauses: Clause 4 applies generally to safety related work practices; Clause 5 applies to safety related maintenance requirements for electrical equipment and installations in workplaces, and Clause 6 supplements or modifies Clause 4 with safety requirements for special equipment.

As indicated above, the purpose of the standard is to provide a practical safe working area for workers and part of this is establishing the Shock Protection Boundary and Arc Flash Hazard Boundary.

The shock protection boundary consists of a limited approach, prohibited approach, and restricted approach. The standard provides tables for qualified workers with approach distances based on a voltage range. Limitations are also provided for unqualified persons.

An Arc Flash Hazard Analysis is used to determine an Arc Flash Protection Boundary and the personal protective equipment (PPE) required to be used by workers within that boundary.

There are two main parts to an Arc Flash Hazard Analysis: Site work to identify potential arc sources and record data about the source; and analysis work to calculate arc flash distances and for complex systems produce a one line diagram modeling the plants power system.

The result of the Arc Flash Hazard Analysis produces the available incident energy and the arc flash distance required for each source location. Additional information may be provided such as the required PPE to be worn by workers. The standard requires labels to be posted at each source location indicating the incident energy and arc distance or hazard risk category. Listing PPE requirements on the label is a good practice to include particularly when you consider how often contractors work on your power system.

Depending on your resources there are several ways an Arc Flash Hazard Analysis can be completed. You can significantly reduce costs if you have the resources to identify and collect the data required for calculating incident energy and arc flash distance. You can also use your own electrical contractors to collect data or you can contract all the work required to complete the study.

A major factor in the cost is the number of sources to be analyzed. A typical amount of sources is between 300 and 600 points to be calculated. That's 300 to 600 sources to collect data on site and return to place 300 to 600 labels.

Keep in mind, a complete study according to the standard includes the development of an Electrical Safety Program

Keywords: Compliance, Safety System Design