Photovoltaic DC inputs — voltage, fault duty and replaceable protection
Start with the PV circuit at the installation point: its maximum string voltage, earthing arrangement and prospective short-circuit current. Use those conditions to identify a complete DC surge protector and its protection modes before comparing discharge-current figures.
Modular surge protective devices for photovoltaic DC inputs, combiner boxes and inverter-side cabinets. This guide covers the DC device, its base and replaceable protective elements. AC distribution SPDs, medium-voltage line arresters, RF protectors and board-level battery protection have separate application requirements.
Choose from the calculated string voltage and the DC connection diagram
CNC’s DC SPD selection page calls for maximum PV string voltage calculated at the lowest expected temperature. It also asks for pole configuration, installation position and the required protection category. Send that calculation with the circuit diagram when requesting a model. [1]
The Phoenix Contact VAL-SPP-T2-1000DC-PV-2+V-UT example distinguishes UOCSTC of 1000 V DC from maximum continuous voltage UCPV of 1200 V DC. Its description covers insulated and grounded PV systems, and its protection modes are DC+ to DC−, DC+ to PE and DC− to PE. Keep those voltage labels and connection modes attached to this model. [2]
Define whether either DC pole is earthed, where the SPD connects and which inverter or combiner input is being protected. Have the supplier confirm the offered base and cartridges against that diagram. A voltage printed in a product name leaves these connection details unresolved.
CNC offers Type 1+2 and Type 2 variants and directs final positions and quantities to the project design, equipment instructions and applicable standards. Include the lightning-protection concept, bonding and installation location in the selection request. [1]
02
Compare PV fault-current duty separately from impulse discharge
BENY’s BUD-1500 data sheet lists a PV short-circuit current rating alongside discharge-current ratings. The different quantities need separate entries in the procurement schedule. [3]
Request the exact order code, declared PV fault rating and the manufacturer’s required disconnection or backup-protection arrangement. Keep a separately declared Imax or Iimp field with its own waveform and mode. Reusing a surge-current figure as the PV short-circuit rating would erase a different operating condition.
The protection-level comparison also needs the mode, test basis and installed connections. Ask the designer to check the equipment’s impulse withstand and the connection layout together. A faster response-time entry alone leaves that coordination incomplete.
BUD-1500 declared quantity
Data-sheet example and meaning to preserve
Maximum PV voltage UCPV
1500 V; retain the PV operating-voltage designation. [3]
PV short-circuit rating ISCPV
10 kA; evaluate against the fault duty at the selected connection point. [3]
40 kA with an 8/20 µs impulse; the sheet labels this total discharge current. [3]
Voltage protection level Up
≤5.5 kV for this device; assess with the protected equipment and installation. [3]
03
Order the base, protection cartridges and service indication as one package
BENY describes BUD-1500 as a base with three plug-in MOV protection modules, mechanical thermal disconnection and a red fault flag; its remote signaling contact is optional. Confirm the ordered monitoring option and replacement-module identity. [4]
Use the manufacturer’s circuit drawing to identify the protective elements in each branch. MOV elements and their thermal-disconnection arrangement form the documented example here. A gas-discharge tube belongs in the assembly specification only when the selected design identifies it.
The BUD-1500 sheet specifies indoor installation and IP20. Its operation-temperature entry is −40°C to +80°C. These are device conditions; the enclosure and site exposure still need a defined installation arrangement. [3]
Record the actual housing material, terminal conductor types and cross-sections, tightening instructions, mounting clearance, dimensions and mass from the offered assembly’s documents. Distinguish the main DC/PE connections from the optional monitoring terminals. Confirm access for cartridge replacement and the procedure for restoring protection after a fault indication.
Document the installed order code, connection diagram and interpretation of the status indicator at handover. The inspection record should identify which protective element needs attention and the matching replacement, with work performed under the equipment’s isolation and service instructions.
04
PV surge-protector selection record
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
PV circuit: [array/string arrangement, maximum calculated voltage and lowest design temperature]
Connection: [grounded or floating poles, protected modes, combiner/inverter input and installation location]
Lightning concept: [external protection, bonding, required SPD category and coordination]
Fault duty: [prospective PV short-circuit current and manufacturer-declared protection arrangement]
Device ratings: [order code, UCPV, ISCPV, In/Imax/Iimp/Itotal with waveforms and modes, Up and response-time basis]
Package: [base, protective cartridges, thermal disconnection, status indication and remote-contact option]
Installation: [enclosure/environment, terminal types and conductors, mounting space, dimensions and mass]
Service: [replacement codes, indication meaning, isolation instructions and handover documents]
4 companies list this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
CNC Electric
TBC
Lists photovoltaic DC SPD series via its linked CNC Energy range, including pluggable modules and monitoring options.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Share this page
Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 23 October 2026
Buyer questions
Which PV voltage should be sent for SPD selection?
Provide the maximum string voltage calculated for the lowest expected temperature, together with earthing, pole configuration and the installation point. CNC’s selection guidance asks for these application details. [1]
Does the BUD-1500 surge-current figure also specify its PV fault duty?
Its sheet lists ISCPV as 10 kA, In as 20 kA and Itotal as 40 kA. The two discharge entries use an 8/20 µs impulse; the PV short-circuit rating is a separate quantity. [3]
What is included in the BUD-1500 monitoring arrangement?
BENY describes a mechanical fault flag and thermal disconnection for its plug-in MOV modules. The remote signaling contact is an option to specify when ordering. [4]
Sources and evidence scope
Sources checked 2026-10-23T12:23:39+08:00. Original PV DC product documents and application guidance. The model examples retain their own voltage, current and installation conditions.
