Electrical Metering Selection and Installation Support
Electrical Metering Selection and Installation Support
Electricity is an essential energy resource and is an enabler of operations and the effective transport of other key energy resources. It is a critical resource for motor, HVAC and lighting loads throughout a site. Our customers look to gain additional insight into their site's energy use beyond their utility bill. To accomplish this goal, we focus collecting data from the site's main utility meter and subsequent sub-mains at the main distribution panel. We leverage a variety of products to accomplish the monitoring objectives.
Frequently Asked Questions: Electric Meter Selection and Installation
1. Why do I need electric meters?
Electric meters are essential tools for visibility, control, and accountability in your facility’s electrical infrastructure. In a manufacturing environment, where energy is both a major operating cost and a critical resource, metering provides the foundation for informed decision-making and system optimization.
Here’s why you need electric meters:
1. Understand and Control Energy Costs
Utility bills only show total consumption, not how, when, or where energy is used.
Submetering allows you to break down usage by area, process, or equipment, revealing inefficiencies and cost drivers.
2. Detect Waste and Equipment Issues
Meters help identify unexpected load spikes, leaking compressed air systems, inefficient motors, or non-operating hours usage.
Early detection reduces downtime, maintenance costs, and energy waste.
3. Support Process and Production Optimization
By tying energy usage to specific production lines or batch processes, you can calculate energy per unit produced, enabling leaner operations and improved KPIs.
4. Enable Energy Efficiency Projects
Real-time and historical metering data supports energy audits, rebate programs, and capital project justification.
Helps verify savings from VFDs, LED upgrades, HVAC retrofits, and more.
5. Compliance and Sustainability Reporting
Many states (like CA, NY, PA) and local jurisdictions require benchmarking or submetering under laws like Local Law 88, AB 802, or LEED certification.
Meters help meet these requirements and support Scope 2 emissions tracking.
6. Tenant or Departmental Billing
In multi-tenant or shared-use facilities, submeters allow for fair and accurate cost allocation by usage.
Bottom Line:
Electric meters are not just about reading kWh—they are about turning data into action. They provide the transparency and control needed to run your facility more efficiently, reliably, and sustainably.
2. What factors should I consider when selecting a main panel electric meter for bus bar installation?
1. Meter Type and Functionality
Revenue-Grade or Monitoring-Only: Choose revenue-grade if billing or compliance reporting is needed (ANSI C12.20 Class 0.2/0.5).
Energy Parameters: Ensure it measures the right values (e.g., kWh, kVARh, kW demand, power factor, harmonics).
Real-Time vs. Interval Data: For demand management, interval (load profile) recording is essential.
2. Voltage and Current Ratings
Match the meter to your system:
Voltage class (e.g., 208V, 480V, 600V)
System type (e.g., 3-phase 4-wire wye, 3-phase 3-wire delta)
Confirm CT (current transformer) ratings align with expected main feeder amperage (e.g., 400A, 800A, 2000A, etc.).
3. Bus Bar Compatibility
Select a meter system designed for split-core or solid-core CTs that mount directly on bus bars or integrate via flexible Rogowski coils. Verify the CT opening or Rogowski loop size fits your bus bar dimensions.
Ensure the system allows safe installation without de-energizing when necessary (especially with split-core CTs).
4. Communication & Integration
Choose meters with compatible communication protocols:
Modbus RTU/TCP
BACnet MSTP/IP
Pulse outputs, LoRaWAN, or cloud-ready options if needed
Ensure compatibility with your BMS, SCADA, or energy management platform.
5. Form Factor and Enclosure
Determine if the meter is:
Panel-mounted, DIN rail-mounted, or enclosure-based
Rated for NEMA 1/3R/4 or IP-rated if installed outdoors or in harsh environments
6. Accuracy, Safety, and Certifications
Confirm compliance with:
ANSI or IEC accuracy classes
UL/cUL or CE certification
Short-circuit withstand rating of the CTs and meter system
7. Advanced Features (Optional but Beneficial)
Web-based interface or onboard display
Data logging and timestamped events
Alarm or threshold notifications
Time-of-Use (TOU) capability
Pro Tip:
For bus bar installations, consider meter kits that include:
Flexible Rogowski coil CTs (easy to install around thick bus bars)
Pre-calibrated CT + meter sets for plug-and-play integration
CT shorting blocks or fuse protection to maintain safety and serviceability
3. What factors should I consider when selecting a subcircuit electric sub-meter for point of use or sub panels?
When metering downstream circuits (e.g., lighting panels, individual equipment, or production lines), your goal is to capture granular usage data to enable energy management, cost allocation, and equipment performance tracking. The following factors are critical to proper selection:
1. Number of Circuits
Determine how many circuits you need to meter:
Single-load meters for large equipment
Multi-circuit meters (e.g., 3, 12, 24, or 48 channels) for subpanels or branch circuits
Choose a meter that supports per-circuit reporting with total aggregation
2. Voltage and System Configuration
Match the meter to your panel’s voltage:
Common: 120/208V, 277/480V, 600V systems
Verify phase configuration: single-phase 2-wire, split-phase 3-wire, or 3-phase 4-wire
Ensure the meter supports auto-detection or is configurable for different panel types
3. Current Transformer (CT) Type & Range
Choose split-core, solid-core, or Rogowski coil CTs depending on space constraints
Confirm the CT amperage range fits your expected loads (e.g., 50A, 100A, 400A)
Check for CT input compatibility (e.g., 333 mV, 5A, or direct Rogowski input)
4. Form Factor and Mounting Location
Ensure the meter physically fits in or near the subpanel
DIN rail, wall-mount, or panel-mount options
Look for compact meters if space is limited, especially in retrofit applications
Consider UL-rated enclosures for safety and code compliance
5. Communication and Integration
Match communication outputs to your building system:
Modbus RTU/TCP, BACnet, Pulse, LoRaWAN, or Wi-Fi
Ensure easy integration with BMS, EMS, or energy dashboards
For remote sites, wireless or IoT-enabled meters may reduce installation cost
6. Measurement Parameters
Look for meters that measure more than just kWh:
kW, kVAR, power factor, voltage, current, demand, THD
Choose meters with interval logging, timestamped events, or alarm capability if power quality monitoring is needed
7. Accuracy and Certifications
For billing-grade accuracy, choose ANSI C12.20 Class 0.5 or better
For internal monitoring, Class 1.0 or 2.0 may be sufficient
Look for UL, cUL, or CE listings depending on your facility requirements
8. Application-Specific Needs
For tenant billing: select revenue-grade meters with non-resettable totals
For process equipment: prioritize real-time kW and power factor monitoring
For lighting or HVAC loads: multi-circuit metering helps capture grouped usage
Pro Tip:
For panel metering, look for pre-configured kits that include:
CTs sized to your loads
Factory-calibrated accuracy
CT shorting terminals or quick-connect harnesses for simplified install
4. What are the different types of electric meters and what applications does each option serve best?
1. Basic kWh Meters
Measures total energy (kWh) only, with minimal features. Often electromechanical or simple digital display.
Residential metering<br>- Small commercial billing<br>- Entry-level submetering
2. Smart Meters / AMI (Advanced Metering Infrastructure)
Digital meters with two-way communication, interval data, and remote monitoring.
Utility revenue metering<br>- Demand response programs<br>- Grid-integrated smart buildings
3. Multifunction Energy Meters
Measures a range of parameters: kWh, kW, kVAR, power factor, voltage, current, frequency, etc.
Commercial/industrial submetering<br>- Energy audits and load profiling<br>- Monitoring of electrical panels and feeders
4. Revenue-Grade Meters
High-accuracy meters (ANSI C12.20 Class 0.2 or 0.5), often with utility-compliant features for billing.
Tenant cost allocation - Utility-grade billing within campuses or multi-tenant properties - Projects seeking incentives or LEED points
5. Multi-Circuit/Subpanel Meters
Monitors multiple circuits from a single device (e.g., 3, 12, 24, 48+ circuits).
Lighting panels - Data centers - Manufacturing process metering - High-density submetering applications.
6. Branch Circuit Monitors (BCMs)
Fine-grained monitoring at the breaker level in panelboards or switchgear.
Data centers (rack-level monitoring) - High-tech manufacturing - Energy benchmarking & granular diagnostics
7. DIN Rail Meters
Compact meters mounted on DIN rails inside panels. Available in single and multi-phase options.
Space-constrained enclosures - Industrial control panels - Retrofit submetering
8. Portable Power Meters / Power Quality Analyzers
Temporary or portable meters for diagnostics, load studies, and power quality analysis (THD, flicker, imbalance).
Energy audits - Temporary commissioning - Troubleshooting voltage sags/swells or harmonics
9. Pulse Meters / Pulse Output Meters
Emit a pulse for every fixed increment of energy (e.g., 1 pulse per 1 Wh or 10 Wh), used for simple data logging or BMS integration.
Integration with legacy BMS<br>- Waterfall metering with data loggers<br>- Simple usage tracking
10. IoT / Wireless Electric Meters
Cloud-enabled or LoRaWAN/Bluetooth/Wi-Fi-enabled meters for remote access without wiring.
Remote or distributed facilities<br>- Temporary monitoring<br>- Rapid deployment across large sites
Choosing the Right Meter:
When selecting a meter, consider the following:
What are you trying to measure? (total usage vs. detailed performance)
How accurate do you need it to be? (billing vs. monitoring)
Where will it be installed? (space constraints, retrofit needs)
How will you retrieve the data? (local display, BMS, cloud)
Do you need communication? (Modbus, BACnet, pulse, wireless)
5. Can I install the electric metering components by myself?
It depends on your qualifications, the type of electric metering system, and your facility’s safety protocols. While some low-voltage or plug-and-play meters may be straightforward, most electric metering installations—especially those involving current transformers (CTs), high-voltage panels, or main feeders—require professional installation to ensure safety, accuracy, and code compliance.
Here's what you should consider:
1. Voltage Level & Location
Line voltage (120/208V or 277/480V)? This is not DIY territory unless you're a licensed electrician or qualified technician.
Installing in a main switchgear or subpanel? Risk of arc flash, shock, or system interruption.
2. Working with Current Transformers (CTs)
CTs—especially on large feeders or bus bars—must be installed correctly and safely. Miswiring or handling them live can be dangerous or damage the meter.
CT polarity, burden rating, and shorting protocols must be observed to avoid injury or false readings.
3. Code & Compliance
Installation must comply with:
NEC (National Electrical Code)
NFPA 70E Arc Flash Safety Standards
UL / ANSI / utility metering regulations if applicable
Improper install may void warranty, invalidate data for billing, or fail inspection.
4. Integration with BMS or EMS
If your meter communicates via Modbus, BACnet, or TCP/IP, you’ll need to know:
How to configure the device
Assign network addresses
Commission the meter with your system
5. Liability & Safety
If you're not a certified installer or your facility prohibits internal electrical work, self-installation could expose you to liability risks, fire hazards, or insurance issues.
When is self-installation OK?
Plug-and-play meters (e.g., clamp-on sensors, wireless meters, desktop loggers) on low-voltage circuits
You are a qualified person under OSHA and your company’s electrical safety plan
Installations under supervision of a licensed electrician.
6. What installation guidelines should I follow for electric meters?
Proper installation of electric meters is critical for ensuring accurate data, safe operation, and long-term reliability. Whether you're installing meters for submetering, energy monitoring, or billing, following a structured set of guidelines will help prevent errors, damage, or safety hazards.
Here’s a comprehensive checklist of installation best practices for facility engineers, electricians, and energy professionals:
1. Understand Your System Configuration
Verify the voltage level and system type (e.g., 3-phase 4-wire wye, 3-phase 3-wire delta, 1-phase split).
Match the meter’s configuration settings and wiring diagram to your electrical service.
2. Select Correct Current Transformers (CTs)
Choose CTs rated for expected current levels (e.g., 100A, 400A, 1200A).
Use matching CT ratios (e.g., 400:5 or 400:0.333V) as specified by the meter.
Install CTs with correct orientation (polarity: H1 toward source/load depending on meter instructions).
Always short CTs when not connected to a meter to avoid open-circuit hazards.
3. Follow Electrical Safety Standards
Comply with:
NFPA 70E (Arc Flash Safety)
NEC (National Electrical Code)
OSHA and facility-specific lockout/tagout procedures
Use insulated tools, wear PPE, and perform work under de-energized conditions when possible.
4. Meter Location & Mounting
Mount meters in a cool, dry, vibration-free environment.
Avoid installing near large VFDs, transformers, or other sources of electrical noise.
Ensure adequate clearance for wiring access and heat dissipation.
If outdoors or in dusty environments, use NEMA 4 / IP65 enclosures.
5. Verify Communication Requirements
Confirm correct wiring for Modbus RTU, BACnet MSTP, Ethernet, pulse, or wireless.
Set device addresses, baud rate, parity, and termination resistors as required.
Document the network map and integration configuration.
6. Perform Verification Testing
After installation, verify:
CTs and voltage taps are wired correctly
Polarity is correct (positive power flow = forward)
Readings match expected values
Communications are functioning with the BMS or EMS
7. Labeling & Documentation
Label CTs, conductors, and meter terminals clearly.
Record:
CT ratios
Phase locations
Meter address/configuration
Panel/circuit ID
Maintain as-built documentation and wiring diagrams for future service.
Pro Tips:
Use shielded twisted pair for RS-485 communication.
Avoid long runs of CT lead wires; use CT-rated extension cables if needed.
Install fused voltage taps for panel safety and serviceability.
Use shorting blocks for CT safety and future meter replacement.
Final Thought:
A meter is only as good as its installation. Following manufacturer instructions, electrical codes, and commissioning best practices ensures you get accurate, actionable data while keeping your facility safe and compliant.
7. How often should electric meters be calibrated?
The calibration frequency of electric meters depends on the type of meter, its purpose (billing vs. monitoring), manufacturer recommendations, and regulatory or utility requirements. While modern digital meters are generally stable, periodic calibration is still important to ensure long-term accuracy and compliance.
General Calibration Guidelines by Meter Type:
Meter Type Recommended Calibration Interval Notes
Revenue-grade meters (ANSI C12.20 Class 0.2/0.5)Every 5–10 years (or per utility requirements) Often regulated by state or utility commission
Non-revenue / monitoring meters - Every 5–7 years For energy management and submetering accuracy
Portable power analyzers - Annually Used for audits or diagnostics; high precision needed
Meters in harsh environments - Every 3–5 years Heat, vibration, and dust can accelerate drift
Newly installed or repaired meters - Immediately after install or service Verify factory calibration was not affected by handling
Calibration Requirements Depend On:
1. Application Purpose
Utility Billing or Tenant Cost Allocation
→ Must follow strict revenue-grade calibration and documentation protocols.
Internal Monitoring or Load Studies
→ More flexible, but still important for reliable insights.
2. Meter Type and Technology
Solid-state digital meters have long-term stability.
Electromechanical meters or analog devices require more frequent calibration.
3. Certifications and Regulations
Local and utility-specific rules may mandate meter accuracy testing (e.g., every 5 years).
NIST-traceable calibration may be required for audit-compliant energy programs.
Calibration Methods:
Bench calibration at certified labs using NIST-traceable equipment.
On-site testing using portable standards (test sets with current injectors and load simulators).
Some advanced meters offer self-diagnostics or drift detection features.
Pro Tip:
Keep a calibration logbook with:
Calibration certificates
Test results
Service records
Calibration due dates
This supports audits, rebates, ISO certifications, and utility contract compliance.
Final Thought:
While digital electric meters are stable, routine calibration ensures data integrity, supports billing accuracy, and maintains trust in your energy management systems. Follow manufacturer and regulatory guidance, and when in doubt—calibrate every 5 years as a best practice.
8. What are the signs that my electric meter needs maintenance or replacement?
Answer from a Metering Professional:
Electric meters are designed for long-term reliability, but like any device exposed to electrical loads and environmental conditions, they can degrade over time. Detecting early signs of malfunction can prevent inaccurate data, billing errors, or even equipment damage.
Here are the most common signs that your electric meter may need maintenance or replacement:
1. Inconsistent or Erratic Readings
Sudden spikes or drops in kWh or kW usage that don’t match historical trends or operational activity.
Mismatches between utility bills and submeter readings.
Negative or reverse power readings in systems that don’t export power.
Likely Cause: CT polarity reversal, signal noise, firmware malfunction, or hardware failure.
2. No Data or Communication Loss
Meter stops sending data to your BMS, EMS, or data logger.
Intermittent or dropped communication (Modbus, BACnet, TCP/IP).
Local display is frozen, blank, or unreadable.
Likely Cause: Power supply issues, loose wiring, failed communication modules, or internal board faults.
3. Physical or Environmental Damage
Cracked housing, corrosion, water ingress, or signs of overheating.
Loose terminals or melted insulation around CTs or voltage taps.
Vibration or dust buildup in harsh industrial environments.
Likely Cause: Environmental stress, improper enclosure rating, or electrical overload.
4. Outdated Technology or Unsupported Firmware
Meter does not support modern protocols (e.g., BACnet/IP, LoRaWAN, cloud sync).
Manufacturer has discontinued support or parts availability.
No remote access, interval logging, or energy analytics capability.
Likely Cause: Obsolescence—time to upgrade.
5. Fails Calibration or Test
Fails utility or NIST-traceable calibration checks.
Drift in accuracy beyond allowed thresholds (e.g., >1% error).
Load tests or phase checks show incorrect values.
Likely Cause: Sensor degradation, aging electronics, or CT accuracy drift.
6. Power Quality or Load Monitoring Errors
Inaccurate reporting of voltage, power factor, THD, or demand.
Alarms for overload, imbalance, or harmonics that aren’t reflected in the system.
Likely Cause: Metering algorithm faults, voltage sensing issues, or configuration errors.
Pro Tip:
Perform annual functional testing and visual inspections, especially on:
Revenue-grade or tenant billing meters
Meters on critical loads (production lines, HVAC, data centers)
Devices exposed to vibration, moisture, or high temperatures
Final Thought:
If your electric meter is over 10 years old, showing irregular behavior, or lacks modern integration capabilities, it may be time for a proactive replacement. Preventive maintenance ensures data accuracy, regulatory compliance, and system reliability.
9. Are smart electric meters available, and what are their benefits?
Yes — smart electric meters are widely available and rapidly becoming the standard in both utility-scale and facility-level metering. These meters go far beyond traditional kWh tracking by enabling real-time data access, remote monitoring, and advanced analytics to support energy optimization, billing, and operational efficiency.
What Is a Smart Electric Meter?
A smart electric meter is a digital device that measures electrical usage and transmits data using two-way communication. Unlike analog meters, smart meters can:
Log interval data (e.g., 15-min kWh, kW, kVAR)
Communicate via Modbus, BACnet, Wi-Fi, Ethernet, LoRaWAN, or cellular
Provide real-time and historical data
Support demand response and automated load control
Key Benefits of Smart Electric Meters
1. Real-Time Visibility
Monitor energy usage in real time at the equipment, panel, or facility level
Quickly detect spikes, inefficiencies, or load anomalies
2. Remote Access & Integration
Access meter data from anywhere via cloud platforms or dashboards
Seamless integration with BMS, EMS, SCADA, or IoT platforms
3. Interval Data & Load Profiling
Tracks energy use in short time intervals (e.g., 5-, 15-, 30-minute)
Supports peak demand analysis, equipment performance tracking, and energy cost optimization
4. Improved Accuracy & Diagnostics
Revenue-grade versions meet ANSI C12.20 standards for billing
Monitors power factor, harmonics (THD), voltage imbalance, and frequency stability
5. Reduced Manual Labor
Eliminates the need for manual meter reading
Reduces errors, labor costs, and time delays in data collection
6. Supports Energy & Sustainability Goals
Enables benchmarking, carbon tracking, and LEED compliance
Identifies opportunities for load shifting, retrofits, and waste reduction
Typical Applications:
Utility billing (AMI/AMR systems)
Multi-tenant commercial buildings
Industrial facilities and campuses
Data centers, hospitals, and critical infrastructure
Grid modernization and demand response programs
Final Thought:
Smart meters are more than just high-tech replacements — they’re the gateway to digital energy management. They empower facilities to make data-driven decisions, improve performance, and reduce costs in real time.
10. How can I optimize the accuracy of my electric meter measurements?
Optimizing the accuracy of your electric meter measurements is essential for reliable data, precise billing, and effective energy management. Whether you're monitoring a main service, subpanel, or specific load, following best practices in installation, configuration, and maintenance will ensure that your metering system delivers true, actionable insights.
12 Key Ways to Optimize Electric Meter Accuracy:
1. Use Revenue-Grade Meters When Precision Is Critical
Select meters compliant with ANSI C12.20 Class 0.2 or 0.5 for billing or cost allocation.
Look for third-party certifications (e.g., UL, CE, NIST traceability).
2. Match CTs and PTs Properly
Use current transformers (CTs) and potential transformers (PTs) that match the meter’s input specs.
Select the correct CT ratio for your expected load range (e.g., 400:5 or 400:0.333V).
Avoid oversizing CTs — too large = poor resolution at low load.
3. Ensure Correct CT Orientation and Polarity
Install CTs with the correct H1 orientation toward the source/load as required.
Verify polarity and phase alignment during commissioning to avoid reverse readings.
4. Use Shielded Cable for Communication and CT Leads
Use twisted shielded cable for RS-485 (Modbus/BACnet) runs.
For long CT runs, use CT-rated extension cables to reduce signal loss and noise.
5. Keep CT Lead Lengths Short
Shorter leads = lower signal degradation.
If long leads are unavoidable, use low-burden CTs or amplified signal CTs.
6. Verify Voltage Tap Connections
Ensure voltage inputs are properly fused and tapped from the correct phase references.
Use precision-rated fuses to protect the meter without introducing drop.
7. Configure the Meter Correctly
Set the correct:
CT and PT ratios
System type (1P2W, 3P4W, etc.)
Wiring mode (delta, wye)
Scaling and register mapping for Modbus/BACnet systems
8. Perform Commissioning and Load Testing
Use a portable power analyzer to validate readings under known load conditions.
Compare with utility readings or known values to verify accuracy.
9. Calibrate Periodically
Follow a 5–10 year calibration schedule (or more frequent if required by law or critical application).
Use NIST-traceable equipment for testing or hire a certified calibration lab.
10. Protect Against Electrical Noise and Disturbances
Avoid placing meters near VFDs, welders, or high-frequency devices without proper shielding.
Use line filters or opto-isolated communication ports where needed.
11. Monitor Power Quality Factors
Install meters that track voltage sags, swells, THD, and frequency to spot anomalies that could skew data or indicate metering issues.
12. Maintain Records and Trend Data
Archive meter configuration settings, calibration logs, and load profile data.
Trend data over time to detect drift, miswiring, or degradation in metering accuracy.
Final Thought:
Accuracy isn’t just about choosing a “high-end meter”—it’s about getting the system integration and installation right. Attention to detail in CT selection, wiring, and configuration will ensure that your data is trustworthy and actionable.
11. How do I get started?
To get started, reach out to us at sales@emergentmetering.com or Contact Us for support. We want to equip our customers with the hardware and information needed to have a safe and successful installation as we recognize the power that high quality energy monitoring data can provide.