Arc flash suits exist to protect electrical workers from the extreme dangers of arc flashes while performing their jobs. Arc flash suit ratings are designed to provide information on the protective capabilities of different suits and the conditions they can be used in. These determine the required characteristics, performance, and materials used in arc suits.

Considering which arc flash suit to buy? Learn what to look for in our Arc Flash Suit Buying Guide.

Arc Flash Suit Functionality

To be functional, an arc flash suit must:

  • Be wearable by men and women
  • Be available in several sizes and fit a wide range of people
  • Be ergonomically shaped (comfortable to wear)
  • Include only arc-rated items
  • Include garments such as boots, helmet, gloves that provide full-body protection

Manufacturers of arc flash suits must rely on designers, material scientists, and other professionals (tailors, leatherworkers, etc.) to create functional garments. Arc flash suits must also be tested and proven to fit within the NFPA PPE Arc categories or they will not be deemed safe.

What Are The Features Of Arc Flash Suits?

Arc flash suits consist of a one-piece suit with protective gloves and special socks. The outer layer is made of metalized polyamide fabric, and the inner layer is of hydrophilic cotton fabric that adheres to the body.

It has a suit hood to protect the head. Below the hood, there is a plastic helmet with a wrap. The voltages at workplaces requiring arc suits are extremely large, over 400 kV (at plants up to 800kV), so a visor for face protection and a helmet is needed. Socks have a three-layer structure, and their lower parts are connected by metal buckles to the suit’s legs.

The seams at the suits must be made so that the metalized layers of the fabric come on top of each other to achieve electrical conductivity. Namely, there is a whole mathematical model for calculating the protection of current flow and is taught in vocational textile schools.

Arc Flash Suit Ratings

The arc flash suit ratings are based on the resistance of the suit’s material to energies released during an arc flash. This means how much energy the material can deflect or absorb before it gets damaged or allows for the burning of the skin. The arc flash rating is defined as how much heat energy the arc suit can withstand per square centimeter (cal/cm2.) Arc flash suits with higher resistance have higher ratings and vice versa. 

Arc Flash PPE Categories 

The National Fire Protection Association (NFPA) has defined 4 categories for arc flash suits in its NFPA 70E (2018) guidelines. These are determined by arc incident energy analysis measured as calories per centimeter squared (cal/cm2.) They include the following categories:

  • PPE Category 1: Minimum Arc Rating of 4 cal/cm2
  • PPE Category 2: Minimum Arc Rating of 8 cal/cm2
  • PPE Category 3: Minimum Arc Rating of 25 cal/cm2
  • PPE Category 4: Minimum Arc Rating of 40 cal/cm2

PPE Category 1 Clothing / Gear

The following are arc-rated garments or gear required to fit PPE category 1:

  • Arc rated long sleeve shirt, jacket, pants, coverall with a minimum arc rating of 4 cal/cm2.
  • Face shield with wrap guarding, balaklava, or arc flash suit hood.

Additional garments include:

  • Arc rated jacket, parka, hard hat liner, or rain gear.

PPE Category 2 Clothing / Gear

The following arc-rated garments or gear are required to fit PPE category 2:

  • Arc rated long sleeve shirt, pants, coverall with a minimum of 8 cal/cm2
  • Arc rated flash suit hood or face shield, sock hood (balaclava) with a minimum arc rating of 8 cal/cm2

Additional garments include:

  • Arc rated jacket, parka, hard hat liner, or rain gear.
  • Heavy-duty leather gloves
  • Hard hat, glasses, goggles, hearing protection
  • Leather boots or footwear

PPE Category 3 Clothing / Gear

The following are arc-rated garments or gear required to fit PPE category 3:

  • Arc rated suit jacket, pants, coveralls with a minimum arc rating of 25 cal/cm2.
  • Arc rated flash suit hood with a minimum arc rating of 25 cal/cm2
  • Rubber insulating gloves with leather protectors, or arc-rated gloves

Additional garments include:

  • Arc rated jacket, parka, rain gear, and hard hat liner

PPE Category 4 Clothing / Gear

The following arc-rated garments or gear are required to fit PPE category 4:

  • Arc rated flash suit jacket and pants, or coveralls with a minimum arc rating of 40 cal/cm2.
  • Arc rated flash suit hood with a minimum arc rating of 40 cal/cm2
  • Rubber insulating gloves with leather protectors, or arc-rated gloves

Additional garments include:

  • Arc rated jacket, parka, hard hat liner, or rain gear

To Recap…

Arc flash suits are specially designed safety garments that meet standards set by the National Fire Protection Association. Be sure to only use an arc suit that meets these ratings when working with electrical equipment or in high arc-risk environments.

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