Konrak YRSD-A PV Firefighter Safety Switch
Also known as a rapid shutdown device (RSD), a firefighter emergency shutdown switch or a PV emergency disconnect switch, the YRSD-A de-energises the DC side of a solar array so that the roof can be worked on safely. It opens the DC circuit automatically when the AC supply is switched off, and adds a red emergency stop button and over-temperature protection. Rated to DC 1500 V for one to ten PV strings (YRSD-1A … YRSD-10A), in a sealed IP66 enclosure.
What is it called?
A device that shuts down a photovoltaic array in an emergency goes by many names — on drawings, in tender documents and on site. They all describe the same job: a switch that makes the DC side of a solar installation safe, quickly, when it matters.
Rapid Shutdown Device (RSD)
The generic term used in codes and tender documents for a device that quickly reduces the DC voltage of a photovoltaic array to a safe level.
Firefighter safety switch
The name used by the fire service and by fire-safety engineers: a switch that makes the array safe before anyone goes onto the roof.
PV emergency disconnect switch
The name used on site and by EPCs for the manual emergency device that isolates the DC side in an emergency.
If your specification uses a different term for a rapid shutdown device, tell us — it is almost certainly the same function.
Three ways to make the array safe
The YRSD-A sits on the DC side, between the PV strings and the inverter. In an emergency the DC side can be de-energised automatically, by hand at the unit, or by the device’s own over-temperature protection.
1 · The AC supply is switched off
In an emergency the fire service, an occupant or a remote operator switches off the AC supply at the main switch or distribution board. Nothing has to be touched at the array.
2 · The DC circuit opens automatically
The YRSD-A watches the AC control voltage. When it disappears, the device opens its internal DC isolation switch, so the PV strings are separated from the inverter without anyone entering the roof space.
3 · The emergency button gives 100 % disconnect
As a second, purely manual route, the red mushroom emergency button on the front of the enclosure opens the DC circuit on the spot — for maintenance or when someone is working at the unit.
4 · Over-temperature protection
An internal temperature sensor monitors the enclosure in real time. If the temperature inside rises above about 70 °C, the device cuts off automatically.
One to ten strings
The YRSD-A rapid shutdown switch is built in ten sizes — YRSD-1A through YRSD-10A, one model for each string count — so a single device can cover a one-string household array or a ten-string commercial roof. The larger array-level models switch the whole array with one motor-driven operation.
| Model | PV strings | Typical use |
|---|---|---|
| YRSD-1A | 1 | Single-string residential arrays and retrofit |
| YRSD-2A | 2 | Small residential rooftops |
| YRSD-3A | 3 | Residential and small commercial rooftops |
| YRSD-4A | 4 | Commercial rooftops |
| YRSD-5A | 5 | Commercial rooftops and NEC rapid shutdown projects |
| YRSD-6A | 6 | Commercial and industrial arrays |
| YRSD-7A | 7 | Industrial rooftops and ground-mount arrays |
| YRSD-8A | 8 | Large commercial and industrial arrays |
| YRSD-9A | 9 | Large arrays and small solar plants |
| YRSD-10A | 10 | Array-level rapid shutdown for large systems |
The YRSD-A range
One enclosure family, sized by the number of PV strings.
Front view
Emergency stop button, indicator window and the warning label on the lid.
Side view
MC4 connections on both sides and the mounting bracket on top.
Array-level models (six to ten strings) handle up to 55 A at DC 1500 V. Tell us the string count and the system voltage and we will confirm the exact model.
YRSD-A technical data
| Product series | YRSD-A |
| Function | PV string-level rapid shutdown device / firefighter safety switch |
| Models | YRSD-1A … YRSD-10A — one model for each number of PV strings |
| Strings | 1 to 10 PV strings |
| String voltage | DC 600 – 1500 V |
| String current | 26 A at DC 1500 V — see the current / voltage table below |
| Max. circuit current (6–10 string models) | 55 A at DC 1500 V |
| Rated voltage (control) | AC 230 V |
| Operating voltage (control) | AC 100 – 270 V |
| Operating temperature | −40 … +85 °C |
| Over-temperature cut-off | internal sensor · approx. 70 °C |
| Emergency stop | red mushroom button · 100 % manual DC disconnect |
| Enclosure | sheet-metal / aluminium enclosure, IP66, with a waterproof vent valve to prevent internal condensation |
| Interface options | knockout hole · cable gland · terminal |
| Connections | MC4-compatible, plug and play |
| Feedback contact | 24 V DC, 300 mA max (status / fault signalling) |
| Endurance | 10,000 mechanical operations; over 1,500 operations under load (DC-PV1) |
| Standards | NEC 2014 · IEC/EN 60947-3 (IEC DC-PV2) |
| Certification | CE · TUV (the internal isolation switch is TUV and CE certified) |
| Warranty | 5 years |
| System voltage | Max. string current |
|---|---|
| DC 800 V | 50 A |
| DC 1000 V | 40 A |
| DC 1250 V | 32 A |
| DC 1500 V | 26 A |
Values quoted for the one- and two-string versions — please confirm the exact rating against the current datasheet for the string count and system voltage of your project.
Why the YRSD-A
Built around four ideas
Fast disconnection, weatherproofing, outdoor durability and over-temperature shutdown.
Clear ON / OFF indication
The indicator window and the marked positions show the state of the device at a glance.
Press to shut down
Pressing the emergency button turns the rapid shutdown function on immediately — 100 % DC disconnect.
Automatic DC disconnect
When the AC supply is lost the DC circuit opens by itself — the array is de-energised before anyone reaches the roof.
100 % manual disconnect
A red mushroom emergency button on the front of the unit gives a direct, hand-operated break of the DC circuit.
Over-temperature protection
An internal sensor cuts the device off above about 70 °C, so a hot enclosure cannot become a fire risk of its own.
IP66 metal enclosure
A sheet-metal enclosure with IP66 protection, plus a waterproof vent valve that prevents condensation forming inside.
Plug and play MC4
MC4-compatible connectors on both sides make the wiring on site quick and repeatable.
Three interface options
Knockout hole, cable gland or terminal — choose the cable entry that matches the installation.
−40 to +85 °C
Rated for the temperature extremes of rooftop and ground-mount installations.
CE and TUV certified, 5-year warranty
CE certified, with the internal isolation switch also TUV certified, a design patent for the enclosure and a five-year warranty.
Where the YRSD-A is used
Wherever a photovoltaic array is mounted on, or close to, a building — and wherever the fire service or a maintenance team may need the DC side to be dead before they go to work.
Mounted at the array
Fitted close to the strings, under or beside the modules.
Ground-mount and utility arrays
String-level shutdown distributed along the rows of a large plant.
Plant rooms and inverter rooms
Installed at the point where strings are gathered before the inverter.
Residential rooftop PV
Rapid shutdown for single- and two-string household arrays.
Commercial and industrial rooftops
Array-level shutdown for buildings where access for the fire service matters.
Ground-mount and utility plants
String-level rapid shutdown distributed along the array rows.
PV plus battery storage
Emergency isolation of the DC side of hybrid and storage installations.
Carports and canopies
Rapid shutdown where PV is installed over parked vehicles and walkways.
Retrofit of existing arrays
A straightforward way to add rapid shutdown to an older installation.
Combiner and junction points
Mounted at the point where strings are gathered before the run to the inverter.
Maintenance and emergency
One place to make the DC side safe for service engineers and the fire service.
Application photographs are illustrative and may show typical installations; they do not depict a specific project.
Built to recognised safety requirements
Rapid shutdown requirements exist because a solar array keeps generating while daylight falls on it. Turning off the inverter does not make the DC side safe — a dedicated shutdown device does.
NEC 2014
The device is designed to meet the rapid shutdown requirements of NEC 2014.
IEC/EN 60947-3
Utilisation category IEC DC-PV2 for photovoltaic DC circuits.
IP66
Sealed sheet-metal enclosure with a waterproof vent valve.
CE · TUV · 5 years
CE certified, with the internal isolation switch also TUV certified, a design patent and a five-year warranty.
Frequently asked questions
What is a PV firefighter safety switch?
It is a device installed on the DC side of a solar array that de-energises the photovoltaic strings in an emergency, so that firefighters and maintenance staff are not exposed to live DC conductors. It is also known as a rapid shutdown device (RSD), a PV emergency disconnect switch or an emergency shutdown switch for solar.
How is it different from an ordinary DC isolator?
An isolator has to be operated by hand at the unit to disconnect the array. The YRSD-A is a rapid shutdown device: it opens the DC circuit automatically when the AC supply is switched off, and it also has a manual emergency button and over-temperature protection.
What triggers the shutdown?
Three things: loss of the AC control voltage (the usual route in an emergency), the emergency stop button on the front of the unit, and the internal over-temperature sensor.
What happens if the mains supply fails?
The device treats the loss of the AC control voltage as a shutdown signal, so the DC circuit opens automatically. In an emergency that is exactly what is wanted.
Can it be operated by hand?
Yes. The red mushroom emergency button gives a 100 % manual disconnect of the DC circuit directly at the unit.
What are the electrical ratings?
String voltage DC 600–1500 V; the maximum string current depends on the system voltage (50 A at 800 V DC, 40 A at 1000 V DC, 32 A at 1250 V DC and 26 A at 1500 V DC). The control supply is AC 100–270 V.
Is it suitable for outdoor installation?
Yes. The enclosure is IP66 sheet metal with a waterproof vent valve, and it is rated from −40 °C to +85 °C.
Which standards apply?
NEC 2014 and IEC/EN 60947-3, utilisation category IEC DC-PV2. The YRSD-A is CE certified, the internal isolation switch is also TUV certified, and the device carries a five-year warranty.
How many strings can one device cover?
The series covers one to ten PV strings — YRSD-1A through YRSD-10A, one model for each string count. The larger array-level models (six to ten strings) switch the whole array with a single motor-driven operation, up to 55 A at DC 1500 V.
What else is it called?
Commonly: rapid shutdown device (RSD), string-level rapid shutdown switch, PV array level rapid shutdown device, solar rapid shutdown switch, PV firefighter safety switch, firefighter emergency shutdown switch, PV emergency disconnect switch, fireman safety switch, PV string safety isolator, DC safety switch for photovoltaic systems and photovoltaic emergency isolation switch.
Need rapid shutdown for your array?
Tell us the system voltage, the number of strings and where the device will be mounted — our team will confirm the right YRSD-A model and can supply samples or OEM versions.
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