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PEBS-H-175
PEBS-H-125
PEBS-H-63
PEBS-H-50
PEBS-S-80 (UL)
PEBS-L-175
PEBS-L-125
PEBS-L-125 (UL1077)
PEBS-L-63
MCB Weatherproof Enclosure (PEBS Series)
DC MCCB (PEMC Series)
PEDS (1500V,16~55A) Series
PEDS-H-R/F (1500V,16~55A) Series
PEDS-H (1500V;40A,50A) Series
PEDS-EL (16~55A) / PEDSC-EL (32A)
PEDSC (1000V&1200V;32A) Series
Remote Tripping Isolator (PERD-100/100T series)
DC Combiner Box (PEJB Series)
AC Combiner Box (PEDB Series)
DC&AC Combiner Box (PEJDB Series)
Intelligent PV Combiner Box (PEJB Series)
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Solar PV Fire Safety Solution Selection Guide: From Rapid Shutdown Devices to Solar Optimizers
In PV systems, safety and energy yield are equally critical. As solar installations continue to expand worldwide, increasingly stringent safety requirements have made rapid shutdown devices an essential consideration in PV system design.
As a professional manufacturer of solar safety solutions for PV and energy storage systems, PROJOY provides complete PV fire safety solutions, including module-level rapid shutdown devices, string-level rapid shutdown devices, and smart solar optimizers. This practical guide covers project assessment, system compatibility, and model selection to help you choose the right solution for your PV projects.
How to Choose the Right Rapid Shutdown Device for a PV System
Choosing the right PV fire safety solution depends on the installation type, required shutdown method, and system functions. Module-level RSD provide individual PV module shutdown, while string-level RSD offer a cost-effective solution for string-level safety control. If module-level monitoring and power optimization are required, a solar optimizer is the better choice.
| Selection Factor | Project Requirement | Recommended Solution |
|---|---|---|
| Shutdown Level | Module-level shutdown required by regulations, project owners, or insurance requirements | Module-Level RSD (PEFS-PL) Solar Optimizer (PEOP) |
| String-level shutdown required for utility-scale PV projects or cost-sensitive applications | String-Level RSD (PEFS-EL) | |
| System Function | Rapid shutdown without module-level monitoring or power optimization | Module-Level RSD (PEFS-PL) String-Level RSD (PEFS-EL) |
| Rapid shutdown with module-level MPPT, optimization, and monitoring capabilities | Solar Optimizer (PEOP) |
Module-Level Rapid Shutdown Device Selection Guide (PEFS-PL)
PROJOY PEFS-PL module-level rapid shutdown device provides individual shutdown protection for solar panels, helping PV systems meet module-level safety requirements. The PEFS-PL selection process includes three steps: checking PV module compatibility, selecting the right shutdown configuration, and matching the required control box.
Step 1: Check PV Module Compatibility
Electrical Parameters
Select the PEFS-PL model according to the module open-circuit voltage (Voc) and short-circuit current (Isc).
| Model | Module Voc Requirement | Module Isc Requirement |
|---|---|---|
| PEFS-PL80S | <80V | ≤20A |
| PEFS-PL120S | <60V | ≤20A |
Cable Length Selection
Choose the suitable RSD cable option based on the PV module cable length:
- Longer built-in cables → Option I (standard cable length RSD)
- Shorter built-in cables → Option II (compatible cable length RSD)
Step 2: Select the Right Module-Level RSD Model
The PEFS-PL model selection depends on two key factors: the required shutdown voltage level and the number of PV modules connected to each rapid shutdown device.
Select the Voltage Class
- PEFS-PL80S: For PV modules with Voc <80V
- PEFS-PL120S: For PV modules with Voc <60V
Select the Connection Configuration
| Module Connection Configuration | Product Illustration | Recommended Model |
|---|---|---|
| 1-to-1 (1 module) | PEFS-PL80S-11 |  |
| 1-to-2 (2 modules) | PEFS-PL80S-21 / PEFS-PL120S-11 |  |
| 1-to-4 (4 modules) | PEFS-PL120S-21 | |
For the PEFS-PL120S solution, two PV modules are connected in series before connecting to the rapid shutdown device. Therefore, the Voc of each individual module should be below 60V, and the total voltage after series connection should remain below 120V.
Step 3: Select the Rapid Shutdown Control Box
After determining the number of rapid shutdown devices, select the suitable control box according to system requirements.
Emergency Stop Button Options
- PCY: Emergency stop button with lock and key
- PCZS: Emergency stop button without lock
Control Box Capacity Selection
| Control Box Model | Maximum RSD Quantity |
|---|---|
| PEFS-PCY/PCZS-S-60-11 | 30 units |
| PEFS-PCY/PCZS-S-180-31 | 90 units |
| PEFS-PCY/PCZS-S-480-81 | 240 units |
Module-Level Rapid Shutdown Device (PEFS-PL) Selection Example
A PV project consists of 176 PV modules (545W). Each module has a Voc of 50.2V and an Isc of 17.1A. The modules use a three-part junction box design with short built-in cables. The project requires a 1-to-2 rapid shutdown configuration, compliance with <80V shutdown requirements, and a lockable emergency stop button.
• Module Voc <80V → Select PEFS-PL80S
• 1-to-2 configuration → Select PEFS-PL80S-21
• Number of RSDs: 176 ÷ 2 = 88 units
• Control box capacity: 88 units → Select PEFS-PCY-S-180-31
• 1-to-2 configuration → Select PEFS-PL80S-21
• Number of RSDs: 176 ÷ 2 = 88 units
• Control box capacity: 88 units → Select PEFS-PCY-S-180-31
Final selection:
PEFS-PL80S-21 (Option II) + PEFS-PCY-S-180-31
PEFS-PL80S-21 (Option II) + PEFS-PCY-S-180-31
String-Level Rapid Shutdown Device Selection Guide (PEFS-EL)
PROJOY PEFS-EL string-level rapid shutdown device is designed for PV systems that require reliable string-level shutdown protection. The PEFS-EL selection process includes three steps: determining the required pole configuration, confirming voltage and current requirements, and selecting the suitable model according to parameters.
Step 1: Determine the Number of Poles Based on PV Strings
The PEFS-EL series offers different pole configurations to match various PV system designs. Two poles correspond to one PV string, so the required pole configuration can be selected according to the number of connected strings.
| Number of PV Strings | Required Pole Configuration | Product Illustration |
|---|---|---|
| 1–2 strings | 4 poles |  |
| 3–5 strings | 6–10 poles |  |
| 6–10 strings | 12–20 poles |  |
Step 2: Confirm Voltage and Current Requirements
After determining the pole configuration, confirm whether the voltage and current ratings meet the PV system requirements.
Voltage Requirement
String Voc × 1.15
Current Requirement
String Isc × 1.25
Step 3: Select the Right PROJOY String-Level RSD Model
Compare the required pole configuration, voltage, and current with the PEFS-EL specification table. The suitable model can be selected when all parameters meet the project requirements.
String-Level Rapid Shutdown Device (PEFS-EL) Selection Example
A PV project uses a 2-string inverter with a string Voc of 850V and Isc of 15A.
• String quantity: 2 strings → 4 poles → Y=4
• Voltage requirement: 850V × 1.15 = 977.5V → Select 1000V
• Current requirement: 15A × 1.25 = 18.75A
• Voltage requirement: 850V × 1.15 = 977.5V → Select 1000V
• Current requirement: 15A × 1.25 = 18.75A
Final selection:
PEFS-EL40-4-P2
PEFS-EL40-4-P2
Solar Optimizer Selection Guide (PEOP)
Step 1: Select the Right Solar Optimizer Model
Select the Model Based on Module Connection Configuration
Select the solar optimizer model according to the number of connected PV modules:
- 1-to-1 configuration: Select PEOP-700
- 1-to-2 configuration: Select PEOP-1000, PEOP-1200, or PEOP-1400
| Module Connection Configuration | Model | Maximum Power per Channel | Maximum Input Current |
|---|---|---|---|
| 1-to-1 | PEOP-700 | 700W | 14A |
| 1-to-2 | PEOP-1000 | 500W + 500W | 14A / 14A |
| 1-to-2 | PEOP-1200 | 600W + 600W | 16A / 16A |
| 1-to-2 | PEOP-1400 | 700W + 700W | 20A / 20A |
Confirm PV Module Electrical Parameters
The selected solar optimizer should meet the following module requirements:
Module Voc: ≤60V
Module Isc: ≤ optimizer short-circuit current rating
Module Imax: ≤ optimizer maximum operating current rating
Module power: ≤ optimizer maximum power per channel
Module Isc: ≤ optimizer short-circuit current rating
Module Imax: ≤ optimizer maximum operating current rating
Module power: ≤ optimizer maximum power per channel
Step 2: Configure DTU and Gateway Quantity
The Solar Optimizer requires DTUs and gateways for communication and monitoring.
DTU
One DTU can connect with a maximum of 50 optimizers.
The actual communication distance should be ≤50m.
Gateway
One gateway can connect with a maximum of 10 DTUs.
The distance between the farthest DTU and gateway should be ≤300m.
PROJOY Solar Optimizer (PEOP) Selection Example
A PV project uses 294 PV modules (535W). Each module has a Voc of 50.2V, Isc of 16.8A, and Imax of 15.2A. The project requires a 1-to-2 optimizer configuration.
Optimizer model selection:
A 1-to-2 configuration is required. PEOP-1200 supports up to 600W per channel, which meets the module power and electrical requirements.
• Optimizer quantity: 294 ÷ 2 = 147 optimizers
• DTU quantity: 147 ÷ 50 ≈ 3 DTUs
• Gateway quantity: 3 DTUs require 1 gateway
Final Selection:
PEOP-1200 + 3 DTUs + 1 Gateway
PEOP-1200 + 3 DTUs + 1 Gateway
Which Solar Rapid Shutdown Solution Is Right for Your Project
| Shutdown Performance | PROJOY Solution | Cost Level | Recommended Applications |
|---|---|---|---|
| String-level shutdown | PEFS-EL | Low | Cost-sensitive PV projects requiring reliable string-level shutdown protection |
| Module-level shutdown | PEFS-PL | Medium | PV projects requiring strict module-level safety compliance |
| Module-level shutdown + MPPT optimization + monitoring | PEOP | Medium | Projects requiring intelligent monitoring, energy optimization, and enhanced system performance |
Frequently Asked Questions
Why are rapid shutdown devices important for solar PV systems?
Rapid shutdown devices reduce DC voltage during emergencies, maintenance, or firefighting operations, providing safer access to PV installations.
Are rapid shutdown devices required for all solar PV systems?
Requirements vary by location and installation type. In regions following standards such as NEC 2017 and NEC 2020, rapid shutdown is required for many rooftop PV installations.
What is the difference between module-level and string-level rapid shutdown?
A module-level RSD controls individual PV modules, while a string-level RSD disconnects one or more PV strings. The appropriate solution depends on safety requirements, system design, and project budget.
How do I choose the right rapid shutdown solution?
Consider the installation type, required shutdown level, PV module parameters, monitoring requirements, and available budget. Choose PEFS-EL for string-level shutdown, PEFS-PL for module-level safety, or PEOP when optimization and monitoring are also required.
What are the common selection mistakes?
Common mistakes include overlooking module compatibility, voltage and current ratings, connection configuration, control box capacity, and monitoring requirements.
What are the advantages of PROJOY solar optimizers?
PROJOY solar optimizers combine module-level MPPT, rapid shutdown, and real-time monitoring to improve PV system safety, energy performance, and maintenance efficiency.
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