Coordination Studies

Ensuring Your Electrical System Fails Safely

When a fault occurs in your electrical system, only the nearest protective device should operate—not devices upstream that take out entire buildings. Poor coordination is why a simple lighting circuit fault can shut down an entire manufacturing plant.

A proper coordination study ensures faults are isolated quickly with minimum disruption. The goal: "Selectivity"—only the protective device closest to the fault operates, leaving the rest of the system energized.

What is a Coordination Study?

A coordination study analyzes the time-current characteristics of all protective devices (circuit breakers, fuses, relays) in your electrical distribution system to ensure they operate in the correct sequence during fault conditions.

Analysis Includes:

• Short circuit current calculations at all points
• Protective device time-current curves
• Relay settings and coordination
• Arc flash reduction opportunities
• Equipment interrupting capacity verification

The Standard: Coordination interval of 0.2-0.4 seconds minimum between protective devices ensures only the device nearest the fault operates.

Why This Service is Critical

Minimize Downtime

Without coordination: Minor faults trip main breakers, shutting down entire facilities

Industry Statistics:

• Average unplanned outage cost: $5,600-$9,000 per minute (industrial)
• One poorly coordinated fault can cost more than 100 coordination studies
• Poor coordination extends outages by 30-120 minutes

Equipment Protection

Properly coordinated devices:

Clear faults faster, reducing equipment damage by 40-60%
Prevent cascading failures throughout the facility
Protect motors, drives, and sensitive electronics from voltage sags
Extend equipment life by 20-30%

Safety Enhancement

Coordination studies often reveal opportunities to:

Reduce arc flash incident energy by 50%+ through faster clearing times
Identify equipment with inadequate interrupting ratings
Optimize relay settings for both protection and safety

Code Compliance

NEC 240.12 requires "selective coordination" for:

Emergency systems (Article 700)
Legally required standby systems (Article 701)
Critical operations power systems (Article 708)
Healthcare facilities (Article 517)

Common Problems This Service Solves

1. Nuisance Tripping

A fault in one branch circuit trips the main service breaker, shutting down an entire building. Proper coordination isolates the fault to just the affected circuit.

Real Example: Manufacturing facility experienced 12 plant-wide shutdowns in 6 months due to poor coordination. Each shutdown cost $45,000 in lost production. Coordination study identified solutions, reducing shutdowns to zero over next 12 months. ROI: 540x.

2. Inadequate Interrupting Capacity

Devices rated for 22kA face fault currents of 42kA—a catastrophic failure waiting to happen. The study identifies these dangerous conditions before equipment explodes.

3. Slow Fault Clearing

Without coordination, protective devices operate too slowly, allowing fault current to flow longer. This causes:

• Higher arc flash incident energy (more dangerous to workers)
• Increased equipment damage
• More extensive and costly repairs

4. Emergency System Failures

Critical systems (fire pumps, emergency egress lighting, life safety) lose power during non-emergency faults due to lack of selective coordination—a serious code violation.

5. Unknown System Capacity

Studies reveal whether your system can handle planned expansions or if upgrades are needed first, saving costly mistakes.

When Should You Schedule This Service?

Immediate Need Indicators

• Frequent nuisance tripping
• Main breakers tripping instead of branch devices
• System additions (new equipment, panels, transformers)
• Utility service upgrades
• Recurring equipment damage from faults
• Building expansions or reconfigurations
• Following electrical incidents

Required Frequency

• Every 5 years minimum
• Whenever electrical distribution changes
• Before arc flash study (coordination is prerequisite)

NEC 240.12 Compliance: Healthcare, emergency systems, and critical operations require documented selective coordination.

What to Expect During the Service

Data Gathering (1-2 weeks)

• Single-line diagram verification
• Protective device types, ratings, and settings
• Available fault current from utility
• Equipment nameplate data
• Existing short circuit study review

Analysis (2-3 weeks)

• Short circuit calculations using SKM or ETAP
• Time-current curve plotting for all devices
• Coordination interval verification (0.2-0.4s minimum)
• Alternative device recommendations where gaps exist
• Arc flash reduction opportunities identified

Deliverables

• PE-stamped comprehensive report
• Coordination plots for all circuit paths
• Recommended relay settings changes
• Device replacement recommendations (if needed)
• Implementation priority ranking
• Updated single-line diagrams

Total Timeline: 4-6 weeks for typical commercial/industrial facility. Expedited service available.

ROI & Business Value

Downtime Prevention

Average manufacturing downtime cost:

$5,600/minute

Poor coordination extends outages by:

30-120 min

One prevented extended outage: $168,000-$672,000 saved

Study Investment

$8K-$30K

Depending on system complexity

Break-even:

Prevent just ONE extended outage

Additional Benefits:

• Faster fault clearing reduces equipment damage by 40-60%

• Lower incident energy = reduced PPE costs

• Extended equipment life (20-30% longer)

• OSHA compliance and liability reduction

Industry Standards & Compliance

NEC Requirements:

NEC 240.12

Selective coordination for emergency systems

NEC Article 517

Healthcare facilities

NEC Article 700

Emergency systems

NEC Article 708

Critical operations (COPS)

Industry Standards:

•IEEE 242 (Buff Book): Protection and Coordination
•IEEE 1015: Low Voltage AC Power Circuit Breakers
•IEEE 141 (Red Book): Power Distribution
•NFPA 70E: Electrical Safety (coordination reduces incident energy)

Enforcement: Authority Having Jurisdiction (AHJ) can reject installations lacking required selective coordination documentation.

Ensure Your System Fails Gracefully

The goal isn't to prevent faults—they're inevitable. The goal is to ensure faults only disrupt what they must.

What You Get:

✓ Complete coordination analysis for all protective devices
✓ Time-current coordination curves and plots
✓ Recommended relay settings and device changes
✓ PE-stamped report for code compliance
✓ Arc flash reduction opportunities identified
✓ Priority-ranked implementation roadmap with costs

📧 support@clarkte.com