Which IEC category is described as Origin of installation at the Utility level?

• A. I - Protected Electronic circuits
• B. IV - Origin of installation at the Utility level
• C. II - Receptacle outlet circuit; plug-in loads
• D. III - Distribution wiring including mains

Answer: (B)

In surge protection, the category you choose depends on where in the electrical system the protection is installed relative to the utility. The description "Origin of installation at the Utility level" refers to protection placed at the service entrance, right at the point where the utility feeds the building.

This is category IV, which is designed to withstand the highest energy levels and to intercept surges as close to the utility source as possible before they propagate through the building’s wiring. Downstream categories correspond to protection locations further into the installation: category II covers receptacle outlets and plug-in loads, category III covers distribution wiring including mains inside the building, and category I covers protected electronic circuits or isolated circuits. Since the statement specifies the origin at the utility level, category IV is the correct match.