Selecting Protective Devices Handbook

Introduction

Fuseology

• Overcurrent and Voltage Ratings
• Voltage Ratings & Slash Voltage Ratings
• Amp Rating and Interrupting Rating
• Selective Coordination & Current Limiting
• Non Time-Delay Fuse Operation
• Dual-Element, Time-Delay Fuse Operation
• Dual-Element Fuse Benefits
• Branch Circuit & Application Limited Overcurrent Protective Devices
• Branch Circuit Fuse Selection Chart (600V or less)
• Branch Circuit Fuse Dimensions
• Cooper Bussmann Branch Circuit, Power Distribution Fuses
• Disconnects, Panelboards, & One-Time Fuses
• Fuse Holders, Fuse Blocks, Power Distribution Blocks & Surge Suppression
• High Speed Fuses
• Medium Voltage Fuses

Circuit Breakers

• Interrupting Rating vs. Interrupting Capacity
• Single-Pole Interrupting Capability
• Series Rating: Protecting Circuit Breakers
  • Square D Series Rating Chart
  • Cutler-Hammer Series Rating Chart
  • General Electric Series Rating Chart
  • Siemens Series Rating Chart

General

• Small Conductors
• Tap Conductors

Cable Limiters

Conductors & Terminations

Equipment Protection

• Transformers — 600V or Less 69 - 70
• Transformers — Over 600V 71 - 72
• Photovoltaic (PV) Systems 73 - 75

Component Protection

• Introduction and Current-Limitation
• How to Use Current-Limitation Charts
• Wire & Cable
• Tap Conductor Sizing
• Small Wire (16 & 18 AWG)
• Busway
• HVAC and Refrigeration Equipment
• Transfer Switches
• Ballasts

• Short-Circuit Current Rating Marking Requirements
• Determining Assembly SCCR: Two Sweep Method
• Umbrella Fuse Limits
• Determining Assembly SCCR: Example
• Increasing Assembly SCCR

• Introduction
• Fuses
• Fuse Selectivity Ratio Guide
• Fusible Lighting Panels
• Fuse Selective Coordination Example
• Circuit Breakers: Operation Basics
• Circuit Breakers: Achieving Selective Coordination
• Fuse & Circuit Breaker Mixture
• Mandatory Selective Coordination Requirements
• Why Selective Coordination is Mandatory
• System Considerations
• OCPD Choices for Selective Coordination
• Inspection Checklist
• Objections & Misunderstandings
• Elevator Circuits

Ground Fault Protection

• Introduction & Requirements
• Overcurrent Protective Devices
• GFPR Considerations
• Current-Limitation

• Introduction
• Arc-Flash Protection
• Maintenance Considerations
• Arc-Flash Hazard Analysis
• Arc-Flash Incident Energy Calculator
• Arc-Flash Hazard Analysis
• Arc-Flash Protection Marking

• Branch Circuit Devices and Disconnect Selection Tables
• Motor Branch Circuit Devices
• Motor Circuit Branch Circuit Protection — Is Resettability of Value?

Motor Protection

• Voltage Unbalance & Single-Phasing
• Basic Explanation

Motor Branch Circuit Protection — NEC® 430.52 Explanation

Motor Circuit Notes

Motor Circuits — Group Switching

Motor Circuit Protection Tables

• NEC® Article 430 and Tables Explanation
• 200Vac Three-Phase Motors & Circuits
• 208Vac Three-Phase Motors & Circuits
• 230Vac Three-Phase Motors & Circuits
• 460Vac Three-Phase Motors & Circuits
• 575Vac Three-Phase Motors & Circuits
• 115Vac Single-Phase Motors & Circuits
• 230Vac Single-Phase Motors & Circuits
• 90Vdc Motors & Circuits
• 120Vdc Motors & Circuits
• 180Vdc Motors & Circuits
• 240Vdc Motors & Circuits

Motor Protection — Tips for Electricians & Maintenance Crews

Motor Starter Protection

• Graphic Explanation
• Low Voltage Motor Controllers
• Type 1 vs. Type 2 Protection

Motor Controller & Fuse Selection for Type 2 Protection

• General Electric Company — IEC
• General Electric Company — NEMA
• Rockwell Automation, Allen-Bradley — IEC
• Rockwell Automation, Allen-Bradley — NEMA
• Square D Company — IEC
• Square D Company — NEMA
• Siemens — IEC
• Siemens — NEMA
• Cutler Hammer Freedom Series — IEC
• Cutler Hammer Freedom Series — NEMA

Motor Circuits with Power Electronic Devices — Power Electronic Device Circuit Protection

Motor Circuit Protection — Group Motor Protection

Motor Control Circuit Protection

Medium Voltage Motor Circuits — R-Rated Medium Voltage Fuses

• Fusible Equipment vs. Circuit Breaker Equipment
• Preventive Maintenance

Short Circuit Current Calculations

• Introduction
• Three-Phase Short Circuits
• Single-Phase Short Circuits
• Impedance & Reactance Data
• Conductors & Busways "C" Values

Voltage Drop Calculations

• Ratings of Conductors and Tables to Determine Volt Loss
• Copper Conductors — Ratings & Volt Loss
• Aluminum Conductors — Ratings & Volt Loss

Fuse Diagnostic Sizing Charts

• Ballasts
• Capacitors (NEC® 460)Electric Heat (NEC® 424)Mains, Feeders, Branches
• Motor Loads (NEC® 430)Solenoids (Coils) 251
• Transformers 600V Nominal or Less
• Transformers Over 600V Nominal
• Solid State Devices

Fuse Sizing Guide — Building Electrical Systems Fuse Specifications

• Suggestions
• Suggested Fuse and Fusible Equipment Specifications

Cooper Bussmann Current-Limiting Fuse Let-Through Data

Glossary

Electrical Formulas

2008 NEC® Section Index

Index

Fuse Cross Reference & Low-Peak Fuse Upgrade