This training will cover the topic of laboratory testing of equipment, UL listing, and how to read equipment specs.
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1 | UL LISTED EQUIPMENT
1 | UL LISTED EQUIPMENT
WHAT IS UL?
WHAT IS UL?
UL (Underwriters Laboratories) is a renowned global safety consulting and certification company established in 1894. It specializes in ensuring product and system safety through:
Safety Standards: Developing and setting safety standards for diverse industries and products.
Testing and Certification: Conducting comprehensive tests to determine if products meet safety standards, certifying them if they pass.
Global Presence: Operating globally with offices and labs worldwide.
Consumer and Industrial Focus: Providing services for both consumer products and industrial sectors, including fire safety and sustainability.
Educational Initiatives: Offering training programs and research to advance safety knowledge.
Promoting Confidence: UL certifications instill confidence in consumers, businesses, and regulators by ensuring safety and quality.
UL is the most common NRTL (Nationally Recognized Testing Laboratory) used for equipment listing for most consumer and commercial products. This is especially prevalent in electrical components. This means that UL listed products are recognized by OSHA safety and quality standards and comply with governing codes like the NEC, IBC/IRC, etc.
HOW DO COMPANIES GET THEIR PRODUCTS UL LISTED?
HOW DO COMPANIES GET THEIR PRODUCTS UL LISTED?
To get their products UL listed, companies should follow these key steps:
Consultation: Start with an initial consultation with UL to discuss the product and safety standards.
Product Evaluation: UL reviews the product's design, specifications, and may provide guidance for necessary modifications.
Testing: UL conducts various tests to ensure the product meets safety standards, covering aspects like electrical, mechanical, thermal, and environmental factors.
Documentation Review: Verify that product documentation aligns with the tested product.
Factory Inspection: Some cases may involve a factory inspection to assess production processes and quality control.
Certification Decision: UL makes a certification decision based on test results, documentation review, and factory inspection.
Product Marking: Once certified, the product can display the appropriate UL Mark, indicating compliance with safety standards.
Ongoing Compliance: Companies must maintain product quality and safety, with possible follow-up inspections or audits by UL.
Specific requirements and processes can vary based on the product type, industry, and applicable standards, so close collaboration with UL representatives is essential.
WHAT IS THE DIFFERENCE BETWEEN UL LISTED AND UL CERTIFIED?
WHAT IS THE DIFFERENCE BETWEEN UL LISTED AND UL CERTIFIED?
UL Listed: Implies a product meets specific safety standards as determined by UL testing.
UL Certified: Suggests a product not only meets safety standards but may also comply with additional performance or quality criteria.
UL Marks: Both "UL Listed" and "UL Certified" products may bear the UL Mark, but the wording within the mark may differ.
The emblems seen on the right are the most common UL markings. The bottom one is "UL Recognized" which is more common with commercial equipment.
WHY IS THIS IMPORTANT?
WHY IS THIS IMPORTANT?
The information in this chapter is important because it:
Ensures consumer safety by clarifying the significance of "UL Listed" and "UL Certified" labels on products.
Helps manufacturers comply with regulatory standards and accurately label their products.
Provides consumers with insights into product quality and additional attributes, such as energy efficiency.
Prevents misrepresentation of certification labels, which can have legal and reputational consequences.
Supports education and training in fields related to product design, manufacturing, and consumer protection.
FINDING EQUIPMENT LISTINGS
FINDING EQUIPMENT LISTINGS
UL listings per equipment are easiest to locate using the UL Product iQ online tool:
You can create your own login.
This will allow you to search for current and past listings on products if needed for AHJ/utility disputes, etc.
Note that UL is not the only Nationally Recognized Testing Laboratory, so you may need to search for listings using other NRTLs as needed.
OTHER NRTLS
OTHER NRTLS
Common Nationally Recognized Testing Laboratories (NRTLs) in the United States, accredited by OSHA for product safety testing and certification, include:
Underwriters Laboratories (UL): Well-known for various safety certifications.
Intertek (ETL): Provides ETL Listed Marks for certified products.
CSA Group: Offers CSA certification services.
Bureau Veritas North America: Offers NRTL services across various industries.
MET Laboratories: Specializes in electrical product safety testing with the MET Mark.
QPS Evaluation Services: Offers testing and certification for electrical and gas products.
FM Global: Primarily an industrial and commercial property insurer but also offers fire protection and electrical safety product certification.
These NRTLs ensure products meet safety standards and regulations, aiding businesses in demonstrating compliance and enhancing consumer confidence in product safety.
It is worth noting that a mark or listing with these entities can satisfy any listing/testing requirement as per the NEC, IBC/IRC, etc. just as a UL listing or certification would.
2 | LABORATORY TESTING
2 | LABORATORY TESTING
MODULES:
MODULES:
STANDARD TEST CONDITIONS (STC)
STANDARD TEST CONDITIONS (STC)
Standard Test Conditions (STC) are a set of standardized reference conditions used in the solar energy industry for evaluating and comparing the performance of solar panels or modules. Key parameters under STC include an irradiance level of 1,000 W/m² and a temperature of 25°C (77°F).
STC provides a consistent basis for comparing solar panel performance.
Testing under STC allows consumers, manufacturers, and researchers to assess and compare solar panel performance objectively.
Real-world performance may differ from STC ratings due to various environmental factors.
PVUSA TEST CONSIDITONS (PTC)
PVUSA TEST CONSIDITONS (PTC)
PTC (PVUSA Test Conditions) is a set of reference conditions used in the solar energy industry for assessing the performance of photovoltaic (PV) modules and systems. Key parameters under PTC include an irradiance level of 1,000 W/m² (similar to STC) and an ambient temperature of 20°C (68°F).
PTC provides a more realistic representation of solar panel performance compared to STC.
PTC ratings are used to estimate a solar system's actual energy production in real-world applications, helping with project assessments and financial decisions.
Both STC and PTC are most commonly completed by UL
GENERAL PV ELECTRICAL BOS STANDARDS AND TESTING
GENERAL PV ELECTRICAL BOS STANDARDS AND TESTING
A consolidated testing regimen used for various electrical equipment, including PV inverters, PV trunk cables, PV combiner panels, and circuit breakers, encompasses the following key assessments:
Electrical Performance Testing: Includes current-carrying capacity, voltage withstand, overcurrent protection, and short-circuit current rating tests.
Safety and Protection Testing: Validates protection mechanisms against overcurrent, ground faults, arc faults, and dielectric properties.
Environmental Testing: Assesses performance under varying environmental conditions, including temperature, humidity, UV exposure, corrosion, and environmental compatibility.
Mechanical Testing: Evaluates resistance to vibration, shock, impact, and endurance.
Environmental Protection Testing: Examines ingress protection (IP) and NEMA enclosure ratings.
EMC Testing: Measures electromagnetic compatibility and interference resistance.
Certification Testing: Ensures compliance with industry standards and regulations.
Efficiency Testing (for inverters): Measures conversion efficiency.
MPPT Testing (for inverters): Evaluates optimization of solar panel output.
Grid Compatibility Testing (for inverters): Ensures safe grid connection.
Cable Bend Radius Testing (for PV trunk cables): Determines safe installation.
Durability Testing (for PV trunk cables and combiner panels): Assesses long-term performance.
Connector Compatibility Testing (for PV trunk cables): Checks compatibility with connectors.
Tripping Time and Coordination Testing (for circuit breakers): Assesses tripping times and coordination with protective devices.
Load Testing (for circuit breakers): Evaluates performance under various load conditions.
These comprehensive tests collectively ensure the reliability, safety, and compliance of electrical equipment used in PV systems and other applications. Manufacturers collaborate with accredited testing laboratories to validate their products and meet quality and safety standards.
MOUNTING AND RACKING SYSTEMS
MOUNTING AND RACKING SYSTEMS
Laboratory testing for PV (photovoltaic) mounting and racking systems includes a range of assessments to ensure their structural integrity, durability, and safety in solar installations:
Structural Testing: Involves load, deflection, and wind resistance tests to assess the system's structural stability.
Environmental Testing: Includes corrosion resistance, UV exposure, temperature cycling, and wind tunnel tests to evaluate performance in various conditions.
Seismic Testing: Determines the system's ability to withstand seismic forces in earthquake-prone regions.
Electrical Grounding and Bonding: Ensures proper electrical grounding and safety measures are integrated into the system.
Safety and Code Compliance: Validates compliance with local building codes and safety standards.
Installation and Assembly Testing: Evaluates ease of installation and assembly efficiency.
Certification Testing: Ensures compliance with industry standards and regulations.
Durability and Longevity Testing: Assesses long-term performance and endurance.
Foundation Testing (for ground-mounted systems): Analyzes foundation stability.
Compatibility Testing: Checks compatibility with various solar panel types and sizes.
These tests collectively validate the performance, safety, and compliance of PV mounting and racking systems, helping manufacturers provide reliable and code-compliant solutions for solar installations. Manufacturers collaborate with accredited testing laboratories to ensure their products meet industry standards.
3 | UNDERSTANDING EQUIPMENT SPECS
3 | UNDERSTANDING EQUIPMENT SPECS
MODULES
MODULES
Reading PV (photovoltaic) module specifications in layman's terms can be simplified by breaking down the technical jargon into more understandable terms. Here's a guide on how to interpret key PV module specifications:
Wattage (W or kWp):
This is how much electricity the solar panel can generate.
It represents the power output in watts or kilowatts peak (kWp) under standard test conditions (STC), indicating the panel's capacity to produce electricity.
Efficiency (%):
How well the solar panel converts sunlight into electricity.
Efficiency tells you the percentage of sunlight that gets converted into electricity. Higher efficiency means more power from the same sunlight.
Dimensions (Length x Width):
The physical size of the solar panel.
It provides the panel's length and width, helping you estimate how much space it will occupy on your roof or installation area.
Operating Temperature (°C):
The range of temperatures the panel can handle.
It indicates the temperatures at which the panel can work effectively. Panels with a broader range are better for various climates.
Tolerance (%):
How close the panel's actual output is to its rated output.
Tolerance specifies the acceptable range of deviation from the rated power output. For example, if the tolerance is +/- 5%, a 300W panel can produce between 285W and 315W.
Temperature Coefficient (°C or %/°C):
How much the panel's performance changes with temperature.
A negative temperature coefficient means the panel's efficiency decreases as it gets hotter, while a positive one means it's less affected by heat.
Maximum System Voltage (V):
The highest voltage the panel can handle safely.
It's the maximum voltage that the panel can withstand without risking damage. Ensure it matches your system's requirements.
Open-Circuit Voltage (Voc) and Short-Circuit Current (Isc):
Extreme conditions measurements.
These values represent the voltage and current produced by the panel in extreme conditions (no load and full sunlight). They're mainly used for design and safety purposes.
Type of Solar Cells (e.g., Monocrystalline, Polycrystalline, Thin-Film):
The material the panel is made from.
Different types have varying efficiency and cost characteristics. Monocrystalline is known for high efficiency, while polycrystalline is more cost-effective.
Understanding these specifications in simple terms will help you make informed decisions when handing AHJ/Utility disputes regarding module specs. In most cases, we will default to STC ratings but in some cases, AHJs/Utilities may require our calculations to be re-engineered to include PTC standard ratings.
Reading PV (photovoltaic) inverter specifications in layman's terms involves simplifying technical details. Here's how to understand key inverter specs:
Inverter Type (String, Micro, Hybrid):
The type of inverter for your solar system.
String inverters are standard; microinverters are compact; hybrid inverters can store excess energy.
Input Voltage Range (V):
The range of solar panel voltages it can handle.
Ensures the inverter is compatible with your panel's output.
Output Voltage (V):
The electricity it provides for your home.
It's the voltage of the electricity used in your home.
Maximum Power Output (W or kW):
How much electricity it can provide at its peak.
Represents the inverter's capacity to power your home.
Efficiency (%):
How well it converts solar power into electricity.
Higher efficiency means more electricity from your panels.
MPPT Voltage Range (V):
The ideal panel voltage range.
Helps your inverter get the most power from your panels.
Number of MPPT Trackers:
How many sets of panels it can optimize separately.
More trackers mean better performance if panels face different directions.
Dimensions (Length x Width x Height):
How big the inverter is.
Consider the space it needs in your installation area.
Weight (kg or lbs):
How heavy the inverter is.
Affects installation and support requirements.
Operating Temperature Range (°C):
The temperature it can handle.
Ensures it works in your climate.
Grid Compatibility:
How it connects to your electrical grid.
Ensures safe integration with your home's power supply.
Monitoring and Connectivity:
How you can track your system's performance.
Allows you to see how much energy your panels generate.
Understanding these inverter specs helps you choose the right one for your solar energy system, making it easier to power your home with clean energy.
LOAD CENTERS
LOAD CENTERS
Reading load center (also known as electrical panel) specifications in layman's terms involves simplifying technical details. Here's how to understand key load center specs:
Amperage Rating (Amps):
How much electrical capacity it can handle.
Indicates the maximum amount of electricity that can flow through the panel safely.
Voltage Rating (Volts):
The type of electricity it's designed for.
Specifies whether it's suitable for standard household voltage (120V or 240V).
Number of Circuit Breaker Spaces (and/or Circuits):
How many electrical circuits it can support.
Determines how many appliances and outlets you can connect.
Main Breaker or Main Lug:
How it disconnects power to your home.
A main breaker serves as the main on/off switch, while a main lug panel requires an external disconnect switch.
Number of Phases (Single-Phase or Three-Phase):
The type of electricity supply.
Single-phase is typical for homes, while three-phase is for larger commercial or industrial applications.
Dimensions (Height x Width x Depth):
How big the panel is.
Consider the space it needs for installation.
Indoor or Outdoor Use:
Where you can install it.
Specifies whether it's suitable for indoor or outdoor locations.
UL (Underwriters Laboratories) Certification:
A safety seal.
Ensures it meets safety and quality standards.
Circuit Breaker Compatibility:
The types and sizes of breakers it supports.
Determines which breakers you can install for specific circuits.
Number of Knockouts (for Cable Entry):
How many entry points it has.
Shows where cables can enter the panel.
Understanding these load center specifications helps you choose the right electrical panel for your home or building, ensuring safe and reliable power distribution.
BREAKERS
BREAKERS
Reading circuit breaker specifications in layman's terms involves simplifying technical details. Here's how to understand key circuit breaker specs:
Amperage Rating (Amps):
How much electrical load it can handle.
Indicates the maximum current the breaker can safely carry without tripping.
Voltage Rating (Volts):
The type of electrical system it's designed for.
Specifies whether it's suitable for standard household voltage (120V or 240V).
Interrupting Capacity (AIC or kA):
How well it can handle short circuits.
Indicates the maximum fault current it can safely interrupt without damage.
Trip Type (Thermal-Magnetic, Electronic):
How it detects and responds to overloads and short circuits.
Thermal-magnetic breakers use heat and magnetic fields, while electronic ones use electronic sensors.
UL (Underwriters Laboratories) Certification:
A safety seal.
Ensures it meets safety and quality standards.
Number of Poles (1P, 2P, 3P):
How many electrical phases it controls.
Single-pole (1P) for one phase, double-pole (2P) for two phases, and three-pole (3P) for three phases.
Circuit Breaker Type (e.g., Standard, GFCI, AFCI):
Additional safety features, if any.
GFCI protects against ground faults, AFCI against arc faults, and standard breakers handle overloads and short circuits.
Wire Size Compatibility:
The range of wire sizes it can accommodate.
Ensures proper wire connections for safety and performance.
Trip Time:
How quickly it shuts off power during a fault.
Indicates how fast the breaker responds to overloads and short circuits.
Understanding these circuit breaker specifications helps you select the right breaker for your electrical system, ensuring safety and reliable protection against electrical faults.
CABLES & CONDUCTORS
CABLES & CONDUCTORS
Reading cable and conductor specifications in layman's terms involves simplifying technical details. Here's how to understand key cable and conductor specs:
Cable Type (e.g., NM-B, THHN):
The kind of cable it is.
Identifies the cable's purpose and characteristics, such as indoor wiring (NM-B) or individual conductors (THHN).
Wire Gauge (AWG):
The thickness or size of the wire.
Smaller AWG numbers mean thicker wires, capable of carrying more current.
Number of Conductors:
How many wires are inside the cable.
Indicates the number of individual wires bundled together in the cable.
Insulation Material:
The outer covering of the wire.
Describes the material that protects the wire, often PVC or other insulating materials.
Voltage Rating (Volts):
The type of electrical system it's designed for.
Specifies whether it's suitable for standard household voltage (120V or 240V).
Temperature Rating (°C):
The range of temperatures the cable can handle.
Ensures the cable works safely in different environments and conditions.
Ampacity (Amps):
How much current the cable can carry safely.
Indicates the maximum electrical load the cable can handle without overheating.
Shielding (if applicable):
Additional protective layers.
Shields protect the cable from interference, making it suitable for specific applications like data transmission.
Bend Radius:
How sharply the cable can bend.
Indicates the minimum bend radius to prevent damage to the cable.
UL (Underwriters Laboratories) Certification:
A safety seal.
Ensures the cable meets safety and quality standards.
Cable Length:
How long the cable is.
Helps you determine if it's long enough for your wiring needs.
Understanding these cable and conductor specifications helps you select the right cables for your electrical wiring needs, ensuring safety and reliable electrical connections.
RACEWAYS
RACEWAYS
Reading specifications for raceways like EMT (Electrical Metallic Tubing), PVC (Polyvinyl Chloride), and RMC (Rigid Metal Conduit) in layman's terms involves simplifying technical details. Here's how to understand key raceway specs:
Material (e.g., Steel, PVC):
What the raceway is made of.
Identifies the raceway's construction material, which affects its durability and application.
Size (e.g., 1/2 inch, 1 inch):
How big the raceway is.
Specifies the diameter of the raceway, important for fitting wires and cables.
Conduit Type (EMT, PVC, RMC):
The style of the raceway.
Describes the specific design and features of the raceway, like EMT's metal tubing or PVC's plastic pipe.
Wall Thickness or Schedule (for PVC):
How thick the PVC walls are.
Thicker walls provide extra protection but may reduce interior space for wires.
UL (Underwriters Laboratories) Certification:
A safety seal.
Ensures the raceway meets safety and quality standards.
Connection Type (e.g., Couplings, Connectors):
How pieces of raceway connect.
Describes how you join different sections of the raceway for your wiring runs.
Corrosion Resistance (for EMT and RMC):
How well it resists rust and deterioration.
Important for outdoor or corrosive environments; higher resistance means longer lifespan.
Fire Resistance (if applicable):
How well it withstands fire.
Specifies if the raceway is designed to resist fire and its fire rating.
Understanding these raceway specifications helps you choose the right conduit for your electrical wiring needs, ensuring safety and effective wire protection.
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