NFPA 70E is the US standard for electrical safety in the workplace, and it defines how to protect workers from arc flash — a sudden, explosive release of energy from an electrical fault that can reach 19,000 °C and cause fatal burns. Choosing arc-rated PPE comes down to one number: the incident energy at the work location, measured in calories per square centimetre (cal/cm²).
What is an arc flash?
An arc flash occurs when current jumps across an air gap between conductors. The resulting blast produces intense heat, light, pressure, and molten metal. Even at a short distance the thermal energy can cause severe burns, which is why arc-rated clothing and PPE are essential for anyone working on or near energised equipment.
Incident energy and arc rating
The protection a garment provides is its arc rating (ATPV or EBT), expressed in cal/cm². The rule is simple: the arc rating of your PPE must be equal to or greater than the incident energy at the task. Incident energy is determined either by an engineering arc-flash study or by NFPA 70E's PPE Category method.
The NFPA 70E PPE categories
NFPA 70E groups arc-rated PPE into four categories by minimum arc rating:
- PPE Category 1 — minimum arc rating 4 cal/cm²
- PPE Category 2 — minimum arc rating 8 cal/cm²
- PPE Category 3 — minimum arc rating 25 cal/cm²
- PPE Category 4 — minimum arc rating 40 cal/cm²
The older "HRC" (Hazard/Risk Category) terms map directly onto these four categories.
How to select the right PPE
There are two compliant methods:
- Incident-energy analysis — an arc-flash study calculates the exact cal/cm² at each location; you then choose PPE with an equal or higher arc rating.
- PPE Category method — NFPA 70E tables assign a category based on the equipment type, available fault current, and clearing time.
For most tasks a complete kit is the simplest path. Our HRC 2 (8–12 cal) kits cover everyday panel work, while HRC 3 & 4 (25–40+ cal) kits handle higher-energy tasks.
A complete arc-flash kit
Arc protection is a system, not a single garment. A compliant outfit combines an arc-rated coverall or jacket/bib, an arc-rated face shield or flash hood, plus the right supporting equipment:
- Insulated (linesmen) gloves rated for the working voltage.
- Voltage detectors to verify the absence of voltage before work.
- Insulating matting for switchgear and panel rooms.
How we help
As the authorised distributor of LOTO Safety Products in Uzbekistan, we supply complete arc-flash kits and electrical-safety PPE across all four categories, and can advise on the right rating for your tasks. Browse arc flash PPE or contact our team for guidance and a quote.