IEEE 242-2001

IEEE 242-2001 is a technical standard focused on protection and coordination for industrial and commercial power systems. Known as the IEEE Buff Book, it addresses how electrical protection schemes are planned and coordinated so system components can operate safely and selectively during faults. For power, energy, and industry applications, this standard is useful for improving system reliability, limiting equipment damage, and supporting consistent engineering decisions across power distribution installations.

IEEE 242-2001 overview

This standard provides recommended practice guidance for coordinating protective devices in industrial and commercial electrical systems. IEEE 242-2001 is intended to help engineers balance fault clearing, selectivity, and continuity of service while considering the behavior of feeders, transformers, motors, switchgear, and related equipment. It is commonly used as a reference during design and review work where protection settings and coordination studies must support safe, dependable operation under normal and fault conditions.

Typical use cases

IEEE 242-2001 is typically consulted when developing protection schemes for plant distribution networks, commercial building power systems, and facility-level electrical upgrades. It may support coordination studies for breakers, fuses, relays, and motor protection devices, especially where selective isolation is important. The standard is also relevant in equipment specification, system expansion, and maintenance planning for installations that need controlled fault response and minimal interruption to critical loads.

Why this standard matters

Protection and coordination practices have a direct effect on safety, uptime, and equipment life. IEEE 242-2001 helps create a consistent basis for choosing protective devices and setting their operation so faults are cleared without unnecessary outages. That consistency can reduce risk during design, procurement, testing, and commissioning, while also helping teams compare proposed solutions against a recognized engineering reference. In practice, it supports more predictable system performance and better control over fault-related damage.

• Protection and coordination guidance
• Industrial and commercial power systems
• Selective fault clearing considerations
• Coordination studies for distribution equipment
• Recommended practice for engineering review