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Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String
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Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String

Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String

The Projoy PEFS-EL Firefighter Safety Switch — 20-Pole, 10-String, 20A provides string-level rapid shutdown for up to ten PV strings from a single device, designed for larger residential and small C&I rooftop systems in the 8–20 kWp range. Rated 1500V DC, 20A per string — all 20 DC terminals pre-wired with MC4 connectors. Triggered by AC grid loss (≥5 seconds), internal temp sensor (≥70°C) or manual emergency stop. Auto-resets when AC power is restored. IP65, UL 94 V-0, EN 60947-1&3. Controlled via AC circuit — no Wi-Fi, no RF, no networking.

20-pole
10 Strings
20A
Per String
1500V
Max DC
IP65
Rated
Auto
Reset
EN 60947
Certified
⚠ Qualified Installer Required: PV system components must be installed by a suitably qualified and competent person in accordance with BS 7671, IEC 60364-7-712 and MCS installation standards.
Key Features
10-String Coverage — Commercial Scale, Single Device
Twenty poles across ten strings makes this unit suitable for larger residential and small commercial arrays from 8 kWp up to approximately 20 kWp where a 3-phase string inverter or multi-MPPT system with many strings is used. A single AC cable and a single enclosure replace ten individual string isolators.
10 strings8–20 kWpMulti-MPPT / 3-phase inverters
Three Independent Shutdown Triggers — Any One Alone Is Sufficient
The PEFS-EL responds to three separate events, each capable of triggering automatic shutdown independently: (1) AC grid loss for more than 5 seconds — matches international firefighter procedure of cutting AC supply first before tackling the fire; (2) Internal enclosure temperature reaching 70°C — detected by a built-in sensor that monitors the enclosure interior in real time, triggering shutdown before the enclosure becomes a fire hazard itself; (3) Manual emergency stop button on the enclosure face for immediate on-site override.
AC loss ≥5s70°C temp sensorManual stop button
Automatic Reset — Resumes Generation After Routine Grid Outages
Unlike a one-shot fuse, the PEFS-EL resets automatically when AC power is restored after any automatic shutdown. For routine grid outages, ISP maintenance, load shedding or momentary supply interruptions, the system will re-close and resume generation without any manual intervention. Manual reset is only required after activation of the emergency stop button.
Auto-reset on AC restoreNo manual reset for grid outagesMinimises lost generation
Motor-Driven Energy-Storage Spring — 5ms Arc-Quench
Each pole is opened by a motor-driven energy-storage spring mechanism that releases on trigger, driving the contacts apart in under 5 milliseconds. DC arcs have no zero-crossing point and sustain indefinitely if contacts separate slowly — the 5ms response is specifically designed to stretch and quench the DC arc before it can cause contact damage, tracking or fire. Self-cleaning contacts reduce resistance build-up over the device lifetime.
5ms trip responseEnergy-storage springDC arc-quench mechanismSelf-cleaning contacts
MC4 Connectors — Direct Plug-In to Panel String Cables
DC string inputs are pre-wired with MC4 connectors — the universal standard connector used on virtually all solar panels. No stripping, crimping or ferrule insertion required on the DC side. The AC control cable enters via a standard IP65 cable gland.
MC4 pre-wiredNo DC termination workAC gland entry
IP65 Polycarbonate Enclosure — V-0 Flame Retardant
The enclosure is IP65-rated polycarbonate — fully dustproof and protected against water jets from any direction. The body material carries a UL 94 V-0 flame-retardant rating, meaning it will not propagate flame even if exposed to a direct ignition source. Suitable for rooftop, loft or external wall mounting.
IP65UL 94 V-0 flame retardantOutdoor-rated
AC-Circuit Controlled — No Wi-Fi, No RF, No Pairing Required
The PEFS-EL is controlled entirely by the existing AC supply circuit. When AC is present, the switch is closed. When AC drops for 5 seconds, the switch opens. No wireless communication module, no pairing sequence, no signal cable to run from the roof. The control logic is deterministic and immune to network failure — critical for a life-safety device.
AC-circuit logicNo Wi-Fi / RFDeterministic failsafeNo configuration
Technical Specifications
PEFS-EL — 20-Pole 10-String 20A
Number of Poles 20 (2 per string, 10 strings)
Number of Strings 10
Rated Current per String 20A
Max Loop Voltage (DC) 1500V DC
String Voltage Range 300–1500V DC
AC Control Voltage 100–270V AC
AC Nominal Voltage 230V AC
Feedback (FB) Contact Not included — see FB variant
DC Connector Type MC4 (pre-wired)
Triggers and Behaviour
Auto Shutdown: AC Loss Opens after AC loss ≥5 seconds
Auto Shutdown: Temperature Opens when internal temp ≥70°C
Manual Shutdown Emergency stop button on enclosure
Auto Reset Yes — auto-closes when AC power restored
Switching Speed <5ms (energy-storage spring mechanism)
Physical and Environmental
Protection Rating IP65
Flame Retardant Rating UL 94 V-0 (enclosure body)
Operating Temperature −20°C to +50°C
Auto-Trip Temperature +70°C (internal enclosure)
Storage Temperature −40°C to +85°C
Protection Class Class II
Standards and Certifications
Test Standard EN 60947-1 & 3
Certifications CE, ISO 9001, ISO 14001
DC Switch Standard IEC 60947-3 (ed.3.2):2015, UL508i, GB14048.3
Utilisation Category DC-PV0 / DC-PV1
Mechanical Life
Operations (total) 10,000
Operations under load (PV1) >1,500
Manufacturer
Manufacturer Projoy Electric Co., Ltd.
Frequently Asked Questions
Where in the PV system is this installed?
The PEFS-EL is mounted close to the panel array, between the string cables and the inverter input. The AC control cable is connected to a permanent live feed from the distribution board or inverter AC output. MC4 connectors on the DC inputs plug directly into the panel string cables. Position it so the emergency stop button is accessible, typically in the loft or near the array.
Is an FB feedback variant available?
Yes. If your inverter requires confirmation that the rapid shutdown device has physically operated, a variant with an FB (feedback) dry contact is available. Check your inverter installation manual for whether FB feedback is required.
Will a routine power cut reset the system automatically?
Yes. The PEFS-EL resets automatically when the AC supply is restored. After a normal grid outage, the switch re-closes and PV generation resumes without manual action. Only activation of the emergency stop button requires a manual reset.
Does this meet UK Building Regulations or MCS requirements?
The PEFS-EL is certified to EN 60947-1 and 60947-3 and CE-marked. BS 7671 requires DC isolation on PV installations. For specific regulatory compliance, consult the current MCS standards and your DNO requirements. Always verify with your qualified installer.
Is a separate AC isolator also required?
Yes. The PEFS-EL handles DC-side string isolation only. A separate AC isolator at the inverter output remains required by BS 7671 and MCS. Projoy’s PEAS series AC isolators (also available here) are designed for this purpose.
Related Products
Projoy Battery Isolator with Enclosure (PEBS-L)
DC MCB for battery-inverter circuits
Projoy DC Surge Protector (PESP)
SPD for DC PV string protection
$286.26

Original: $817.90

-65%
Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String—

$817.90

$286.26

More Images

Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String - Image 2

Projoy Firefighter Safety Switch 20 Pole 10 String with MC4 20A per String

The Projoy PEFS-EL Firefighter Safety Switch — 20-Pole, 10-String, 20A provides string-level rapid shutdown for up to ten PV strings from a single device, designed for larger residential and small C&I rooftop systems in the 8–20 kWp range. Rated 1500V DC, 20A per string — all 20 DC terminals pre-wired with MC4 connectors. Triggered by AC grid loss (≥5 seconds), internal temp sensor (≥70°C) or manual emergency stop. Auto-resets when AC power is restored. IP65, UL 94 V-0, EN 60947-1&3. Controlled via AC circuit — no Wi-Fi, no RF, no networking.

20-pole
10 Strings
20A
Per String
1500V
Max DC
IP65
Rated
Auto
Reset
EN 60947
Certified
⚠ Qualified Installer Required: PV system components must be installed by a suitably qualified and competent person in accordance with BS 7671, IEC 60364-7-712 and MCS installation standards.
Key Features
10-String Coverage — Commercial Scale, Single Device
Twenty poles across ten strings makes this unit suitable for larger residential and small commercial arrays from 8 kWp up to approximately 20 kWp where a 3-phase string inverter or multi-MPPT system with many strings is used. A single AC cable and a single enclosure replace ten individual string isolators.
10 strings8–20 kWpMulti-MPPT / 3-phase inverters
Three Independent Shutdown Triggers — Any One Alone Is Sufficient
The PEFS-EL responds to three separate events, each capable of triggering automatic shutdown independently: (1) AC grid loss for more than 5 seconds — matches international firefighter procedure of cutting AC supply first before tackling the fire; (2) Internal enclosure temperature reaching 70°C — detected by a built-in sensor that monitors the enclosure interior in real time, triggering shutdown before the enclosure becomes a fire hazard itself; (3) Manual emergency stop button on the enclosure face for immediate on-site override.
AC loss ≥5s70°C temp sensorManual stop button
Automatic Reset — Resumes Generation After Routine Grid Outages
Unlike a one-shot fuse, the PEFS-EL resets automatically when AC power is restored after any automatic shutdown. For routine grid outages, ISP maintenance, load shedding or momentary supply interruptions, the system will re-close and resume generation without any manual intervention. Manual reset is only required after activation of the emergency stop button.
Auto-reset on AC restoreNo manual reset for grid outagesMinimises lost generation
Motor-Driven Energy-Storage Spring — 5ms Arc-Quench
Each pole is opened by a motor-driven energy-storage spring mechanism that releases on trigger, driving the contacts apart in under 5 milliseconds. DC arcs have no zero-crossing point and sustain indefinitely if contacts separate slowly — the 5ms response is specifically designed to stretch and quench the DC arc before it can cause contact damage, tracking or fire. Self-cleaning contacts reduce resistance build-up over the device lifetime.
5ms trip responseEnergy-storage springDC arc-quench mechanismSelf-cleaning contacts
MC4 Connectors — Direct Plug-In to Panel String Cables
DC string inputs are pre-wired with MC4 connectors — the universal standard connector used on virtually all solar panels. No stripping, crimping or ferrule insertion required on the DC side. The AC control cable enters via a standard IP65 cable gland.
MC4 pre-wiredNo DC termination workAC gland entry
IP65 Polycarbonate Enclosure — V-0 Flame Retardant
The enclosure is IP65-rated polycarbonate — fully dustproof and protected against water jets from any direction. The body material carries a UL 94 V-0 flame-retardant rating, meaning it will not propagate flame even if exposed to a direct ignition source. Suitable for rooftop, loft or external wall mounting.
IP65UL 94 V-0 flame retardantOutdoor-rated
AC-Circuit Controlled — No Wi-Fi, No RF, No Pairing Required
The PEFS-EL is controlled entirely by the existing AC supply circuit. When AC is present, the switch is closed. When AC drops for 5 seconds, the switch opens. No wireless communication module, no pairing sequence, no signal cable to run from the roof. The control logic is deterministic and immune to network failure — critical for a life-safety device.
AC-circuit logicNo Wi-Fi / RFDeterministic failsafeNo configuration
Technical Specifications
PEFS-EL — 20-Pole 10-String 20A
Number of Poles 20 (2 per string, 10 strings)
Number of Strings 10
Rated Current per String 20A
Max Loop Voltage (DC) 1500V DC
String Voltage Range 300–1500V DC
AC Control Voltage 100–270V AC
AC Nominal Voltage 230V AC
Feedback (FB) Contact Not included — see FB variant
DC Connector Type MC4 (pre-wired)
Triggers and Behaviour
Auto Shutdown: AC Loss Opens after AC loss ≥5 seconds
Auto Shutdown: Temperature Opens when internal temp ≥70°C
Manual Shutdown Emergency stop button on enclosure
Auto Reset Yes — auto-closes when AC power restored
Switching Speed <5ms (energy-storage spring mechanism)
Physical and Environmental
Protection Rating IP65
Flame Retardant Rating UL 94 V-0 (enclosure body)
Operating Temperature −20°C to +50°C
Auto-Trip Temperature +70°C (internal enclosure)
Storage Temperature −40°C to +85°C
Protection Class Class II
Standards and Certifications
Test Standard EN 60947-1 & 3
Certifications CE, ISO 9001, ISO 14001
DC Switch Standard IEC 60947-3 (ed.3.2):2015, UL508i, GB14048.3
Utilisation Category DC-PV0 / DC-PV1
Mechanical Life
Operations (total) 10,000
Operations under load (PV1) >1,500
Manufacturer
Manufacturer Projoy Electric Co., Ltd.
Frequently Asked Questions
Where in the PV system is this installed?
The PEFS-EL is mounted close to the panel array, between the string cables and the inverter input. The AC control cable is connected to a permanent live feed from the distribution board or inverter AC output. MC4 connectors on the DC inputs plug directly into the panel string cables. Position it so the emergency stop button is accessible, typically in the loft or near the array.
Is an FB feedback variant available?
Yes. If your inverter requires confirmation that the rapid shutdown device has physically operated, a variant with an FB (feedback) dry contact is available. Check your inverter installation manual for whether FB feedback is required.
Will a routine power cut reset the system automatically?
Yes. The PEFS-EL resets automatically when the AC supply is restored. After a normal grid outage, the switch re-closes and PV generation resumes without manual action. Only activation of the emergency stop button requires a manual reset.
Does this meet UK Building Regulations or MCS requirements?
The PEFS-EL is certified to EN 60947-1 and 60947-3 and CE-marked. BS 7671 requires DC isolation on PV installations. For specific regulatory compliance, consult the current MCS standards and your DNO requirements. Always verify with your qualified installer.
Is a separate AC isolator also required?
Yes. The PEFS-EL handles DC-side string isolation only. A separate AC isolator at the inverter output remains required by BS 7671 and MCS. Projoy’s PEAS series AC isolators (also available here) are designed for this purpose.
Related Products
Projoy Battery Isolator with Enclosure (PEBS-L)
DC MCB for battery-inverter circuits
Projoy DC Surge Protector (PESP)
SPD for DC PV string protection

Product Information

Shipping & Returns

Description

The Projoy PEFS-EL Firefighter Safety Switch — 20-Pole, 10-String, 20A provides string-level rapid shutdown for up to ten PV strings from a single device, designed for larger residential and small C&I rooftop systems in the 8–20 kWp range. Rated 1500V DC, 20A per string — all 20 DC terminals pre-wired with MC4 connectors. Triggered by AC grid loss (≥5 seconds), internal temp sensor (≥70°C) or manual emergency stop. Auto-resets when AC power is restored. IP65, UL 94 V-0, EN 60947-1&3. Controlled via AC circuit — no Wi-Fi, no RF, no networking.

20-pole
10 Strings
20A
Per String
1500V
Max DC
IP65
Rated
Auto
Reset
EN 60947
Certified
⚠ Qualified Installer Required: PV system components must be installed by a suitably qualified and competent person in accordance with BS 7671, IEC 60364-7-712 and MCS installation standards.
Key Features
10-String Coverage — Commercial Scale, Single Device
Twenty poles across ten strings makes this unit suitable for larger residential and small commercial arrays from 8 kWp up to approximately 20 kWp where a 3-phase string inverter or multi-MPPT system with many strings is used. A single AC cable and a single enclosure replace ten individual string isolators.
10 strings8–20 kWpMulti-MPPT / 3-phase inverters
Three Independent Shutdown Triggers — Any One Alone Is Sufficient
The PEFS-EL responds to three separate events, each capable of triggering automatic shutdown independently: (1) AC grid loss for more than 5 seconds — matches international firefighter procedure of cutting AC supply first before tackling the fire; (2) Internal enclosure temperature reaching 70°C — detected by a built-in sensor that monitors the enclosure interior in real time, triggering shutdown before the enclosure becomes a fire hazard itself; (3) Manual emergency stop button on the enclosure face for immediate on-site override.
AC loss ≥5s70°C temp sensorManual stop button
Automatic Reset — Resumes Generation After Routine Grid Outages
Unlike a one-shot fuse, the PEFS-EL resets automatically when AC power is restored after any automatic shutdown. For routine grid outages, ISP maintenance, load shedding or momentary supply interruptions, the system will re-close and resume generation without any manual intervention. Manual reset is only required after activation of the emergency stop button.
Auto-reset on AC restoreNo manual reset for grid outagesMinimises lost generation
Motor-Driven Energy-Storage Spring — 5ms Arc-Quench
Each pole is opened by a motor-driven energy-storage spring mechanism that releases on trigger, driving the contacts apart in under 5 milliseconds. DC arcs have no zero-crossing point and sustain indefinitely if contacts separate slowly — the 5ms response is specifically designed to stretch and quench the DC arc before it can cause contact damage, tracking or fire. Self-cleaning contacts reduce resistance build-up over the device lifetime.
5ms trip responseEnergy-storage springDC arc-quench mechanismSelf-cleaning contacts
MC4 Connectors — Direct Plug-In to Panel String Cables
DC string inputs are pre-wired with MC4 connectors — the universal standard connector used on virtually all solar panels. No stripping, crimping or ferrule insertion required on the DC side. The AC control cable enters via a standard IP65 cable gland.
MC4 pre-wiredNo DC termination workAC gland entry
IP65 Polycarbonate Enclosure — V-0 Flame Retardant
The enclosure is IP65-rated polycarbonate — fully dustproof and protected against water jets from any direction. The body material carries a UL 94 V-0 flame-retardant rating, meaning it will not propagate flame even if exposed to a direct ignition source. Suitable for rooftop, loft or external wall mounting.
IP65UL 94 V-0 flame retardantOutdoor-rated
AC-Circuit Controlled — No Wi-Fi, No RF, No Pairing Required
The PEFS-EL is controlled entirely by the existing AC supply circuit. When AC is present, the switch is closed. When AC drops for 5 seconds, the switch opens. No wireless communication module, no pairing sequence, no signal cable to run from the roof. The control logic is deterministic and immune to network failure — critical for a life-safety device.
AC-circuit logicNo Wi-Fi / RFDeterministic failsafeNo configuration
Technical Specifications
PEFS-EL — 20-Pole 10-String 20A
Number of Poles 20 (2 per string, 10 strings)
Number of Strings 10
Rated Current per String 20A
Max Loop Voltage (DC) 1500V DC
String Voltage Range 300–1500V DC
AC Control Voltage 100–270V AC
AC Nominal Voltage 230V AC
Feedback (FB) Contact Not included — see FB variant
DC Connector Type MC4 (pre-wired)
Triggers and Behaviour
Auto Shutdown: AC Loss Opens after AC loss ≥5 seconds
Auto Shutdown: Temperature Opens when internal temp ≥70°C
Manual Shutdown Emergency stop button on enclosure
Auto Reset Yes — auto-closes when AC power restored
Switching Speed <5ms (energy-storage spring mechanism)
Physical and Environmental
Protection Rating IP65
Flame Retardant Rating UL 94 V-0 (enclosure body)
Operating Temperature −20°C to +50°C
Auto-Trip Temperature +70°C (internal enclosure)
Storage Temperature −40°C to +85°C
Protection Class Class II
Standards and Certifications
Test Standard EN 60947-1 & 3
Certifications CE, ISO 9001, ISO 14001
DC Switch Standard IEC 60947-3 (ed.3.2):2015, UL508i, GB14048.3
Utilisation Category DC-PV0 / DC-PV1
Mechanical Life
Operations (total) 10,000
Operations under load (PV1) >1,500
Manufacturer
Manufacturer Projoy Electric Co., Ltd.
Frequently Asked Questions
Where in the PV system is this installed?
The PEFS-EL is mounted close to the panel array, between the string cables and the inverter input. The AC control cable is connected to a permanent live feed from the distribution board or inverter AC output. MC4 connectors on the DC inputs plug directly into the panel string cables. Position it so the emergency stop button is accessible, typically in the loft or near the array.
Is an FB feedback variant available?
Yes. If your inverter requires confirmation that the rapid shutdown device has physically operated, a variant with an FB (feedback) dry contact is available. Check your inverter installation manual for whether FB feedback is required.
Will a routine power cut reset the system automatically?
Yes. The PEFS-EL resets automatically when the AC supply is restored. After a normal grid outage, the switch re-closes and PV generation resumes without manual action. Only activation of the emergency stop button requires a manual reset.
Does this meet UK Building Regulations or MCS requirements?
The PEFS-EL is certified to EN 60947-1 and 60947-3 and CE-marked. BS 7671 requires DC isolation on PV installations. For specific regulatory compliance, consult the current MCS standards and your DNO requirements. Always verify with your qualified installer.
Is a separate AC isolator also required?
Yes. The PEFS-EL handles DC-side string isolation only. A separate AC isolator at the inverter output remains required by BS 7671 and MCS. Projoy’s PEAS series AC isolators (also available here) are designed for this purpose.
Related Products
Projoy Battery Isolator with Enclosure (PEBS-L)
DC MCB for battery-inverter circuits
Projoy DC Surge Protector (PESP)
SPD for DC PV string protection