⚡ Code Corner:🔸 NEC Article 270 – Capacitors

📘 What NEC 270.3 says:

What it says:
270.3 Flammable Liquids. Capacitors containing more than 3 gal (11 L) of flammable liquid shall be installed in a vault or outdoor fenced enclosure, or in a manner acceptable to the authority having jurisdiction (AHJ) to minimize the risk of fire.

Why it matters:

• Ampacity and OCPD ensure safe operation under normal and fault conditions.

• Guarding protects unqualified individuals from accidental contact—especially around liquid-filled or high‑voltage systems.

• Proper discharge prevents shock hazards from residual voltage.

💡 Pro Tip: If you're installing capacitors indoors and they contain more than 3 gallons of flammable dielectric fluid, you cannot rely on bollards, signage, or locked doors alone.
To comply with 270.3, the system must be placed inside a code-compliant vault or relocated outdoors in a fenced, locked enclosure that meets NEC Article 110, Part III.

🔧 Bonus Tip:
When planning capacitor installations, always confirm the fluid type and volume—many installers overlook this when submittals don't specify the dielectric's flash point or volume.

🧠 Think it through – Before you choose your answer, consider the risk profile here:

• You're dealing with flammable liquid — more than 11 liters.

• The space is not restricted to qualified personnel only.

• What happens in a fault? Arcing + flammable fluid = fire or explosion hazard.

This is exactly the type of scenario where the NEC draws a hard line: if the quantity of flammable dielectric liquid exceeds 3 gallons, the installation must be physically protected, regardless of access frequency or enclosure type.