Quick Hits

QUICK HIT 02

When You're Allowed More Than One Service

2026 NEC Reference: 230.4(A)–(E)

🎯 What You'll Learn

The one-service rule has several important exceptions.

⚡ WHEN CAN YOU HAVE AN ADDITIONAL SERVICE?

Additional services are allowed for certain special conditions, including:

• Fire pumps

• Emergency systems

• Legally required standby systems

• Optional standby systems

• Interconnected power production sources

• Certain multiple-source reliability arrangements

Special permission from the AHJ can also allow additional services in certain situations.

MORE CONDITIONS

Additional service arrangements can also apply when:

• The calculated load exceeds 2000 amperes at 1000V or less

• A single-phase load exceeds what the utility normally supplies on one service

• Different voltages are required

• Different frequencies are required

• Different phases are required

• Different rate schedules justify separate service

🧠 EXAM-STYLE QUESTION

Name one special-condition load that can justify an additional service.

Answer:

Fire pumps, emergency systems, legally required standby systems, optional standby systems, or interconnected power production sources.

📌 QUICK TAKEAWAY

The rule is one service, but Article 230 gives you specific paths to additional services.

Know the exceptions.

➡️ Next Quick Hit: Service conductors, buildings, and what counts as "outside."

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