The Projoy PEDS Series DC Isolator is a purpose-built DC isolator-disconnector for solar PV systems, providing the externally accessible, lockable means of DC isolation required by BS 7671 (18th Edition) at every grid-connected string inverter. The PEDS-EL enclosure series is the most common variant: a compact IP66 weatherproof unit with a three-position lockable rotary handle, available in 16A, 25A and 32A ratings across 2-pole (1 string) and 4-pole (2 string) configurations, rated to 1500V DC. The switching mechanism uses an energy-storage spring to separate contacts in under 5 milliseconds — regardless of handle speed — quenching DC arcs before they can cause damage. Dual magnetic and gate arc suppression, self-cleaning contacts and −40°C to +70°C full-load operating range. Enclosure body uses UL 94 V-0 imported flame-retardant material with a >300°C deformation point. Certified to IEC/EN 60947-3, TUV, CE, CB, SAA, UL and UKCA. Also available in single-hole, panel-mount, DIN-rail and door-clutch variants for integration into inverter cabinets or combiner boxes. Higher-current 40A and 55A variants available in the PEDS150H series.
1500V
DC Rated
5ms
Spring Trip
IP66
Enclosure
−40/+70°C
Temp Range
UKCA
UK Certified
V-0
Flame Retardant
⚠ Qualified Installer Required: DC isolators for grid-connected PV systems must be installed by a suitably qualified and competent person in accordance with BS 7671, IEC 60364-7-712 and MCS installation standards. Isolators must be correctly rated for the system voltage and current, and clearly labelled.
Variant Overview — Enclosure Series (PEDS-EL) and Mounting Options
Part Number (example)
Current
Poles
Strings
Enclosure
Typical Application
PEDS150-EL16R-2
16A
2P
1 string
IP66 enclosure
Small single-string inverters up to ~3.7 kW
PEDS150-EL25R-2
25A
2P
1 string
IP66 enclosure
Single-string inverters up to ~5.75 kW
PEDS150-EL32R-2
32A
2P
1 string
IP66 enclosure
Single-string inverters up to ~7.4 kW
PEDS150-EL25R-4
25A
4P
2 strings
IP66 enclosure
Dual-MPPT inverters, 2 independent strings
PEDS150-EL32R-4
32A
4P
2 strings
IP66 enclosure
Dual-MPPT inverters, up to ~7.4 kW per string
PEDS150-EL40R-4
40A
4P
2 strings
IP66 enclosure
Higher-current dual-string, e.g. parallel panels
Panel/hole mount (bare)
16–32A
2P/4P
1–2 strings
No enclosure
For integration into existing inverter cabinet
16A–32A PEDS isolators support 2–12 poles (levels) per unit. With jumpers, ratings up to 58A / 1500V are achievable. Current ratings above for single-phase 230V inverter AC output and assume 1:1 DC/AC ratio sizing. Always match to or above the inverter manufacturer's recommended DC isolator rating.
How to Size a DC Isolator for Your Inverter
Three selection criteria
1. Voltage: The isolator rated voltage must be ≥ the system open-circuit voltage (Voc). For most residential single-phase string inverters: Voc is typically 300–800V. The PEDS 1500V rating covers all current residential and C&I systems with margin to spare. 2. Current: Select at or above the string short-circuit current (Isc) × 1.25 (IEC safety factor). For modern 400–600 Wp panels with Isc ≈14A: 14 × 1.25 = 17.5A → use 25A. For higher-current panels (Isc up to 20A): 20 × 1.25 = 25A → use 32A. 3. Poles: 2-pole (2P) for single-string / single-MPPT inverters. 4-pole (4P) for dual-MPPT or dual-string inverters (most modern 3.6–8 kW residential inverters). Check the inverter datasheet for MPPT count.
Key Features
BS 7671 Required DC Isolation at Every String Inverter
BS 7671 (18th Edition) requires a means of isolation on the DC side of every grid-connected PV installation, in addition to the inverter’s internal DC switch. An isolator-disconnector rated to IEC/EN 60947-3 is the correct device type. The PEDS series is specifically rated and certified for this purpose as a PV DC isolator-disconnector, providing the legally required means of safe DC isolation for inverter maintenance or emergency shutdown.
BS 7671 / IEC 60947-3PV DC isolationLegal compliance
1500V DC Rated — Future-Proof for All Current and Emerging Systems
The PEDS series is rated to 1500V DC — the highest system voltage used in current commercial PV installations and well above the voltage of any residential string. Typical residential strings (10–20 panels at 30–40V Voc each) produce open-circuit voltages of 300–800V DC. A 1500V-rated isolator provides a substantial insulation safety margin above the working voltage and ensures the isolator will not break down or track internally even under transient overvoltage conditions.
1500V DC ratedResidential: 300–800V typicalFull insulation margin
Energy-Storage Spring Mechanism — 5ms Arc Quench
The PEDS uses an energy-storage spring mechanism to drive contacts apart. When the handle is turned to OFF, the spring releases and separates the contacts in under 5 milliseconds, regardless of how slowly the operator turns the handle. This is critical for DC isolation: unlike AC, DC current has no zero-crossing, so if contacts separate slowly the arc will sustain and cause contact erosion, heat and fire risk. The 5ms spring-driven separation ensures the arc is quenched before it can stabilise.
5ms spring mechanismDC arc quenchHandle-speed independent
Dual Arc-Suppression: Magnetic + Gate Extinguishing
Each pole uses both magnetic arc extinguishing and gate arc extinguishing in combination. Magnetic arc extinguishing moves the arc into the extinguishing chamber rapidly; gate extinguishing divides and cools the arc within the chamber. The two mechanisms working together provide reliable arc quenching across the full rated voltage and current range, maintaining the short arcing distance needed to prevent contact damage over the isolator’s life.
Magnetic arc extinguishingGate arc extinguishingShort arcing distance
Self-Cleaning Contacts — Low Resistance Over Full Service Life
The contact surfaces have a self-cleaning wiping action on each operation. This removes the thin oxide layer that forms on metal contacts exposed to air, preventing the gradual increase in contact resistance that would otherwise cause voltage drop, heating and energy loss at the isolator. In PV systems where the isolator may see maximum current during peak generation periods, maintaining low contact resistance is important for both efficiency and thermal safety.
Self-cleaning contactsLow contact resistanceStable over life
IP66 Enclosure — Three-Position Lockable Handle
The PEDS-EL standalone enclosure carries an IP66 weatherproof rating — fully dustproof and protected against high-pressure water jets. Suitable for outdoor mounting, roof structures, loft spaces and exposed plant rooms. The rotary handle has three lockable positions: ON, OFF and a third intermediate position to prevent misoperation. The handle can be locked in the OFF position with a padlock for safe isolation during maintenance, satisfying Electricity at Work Regulations 1989 requirements.
−40°C to +70°C Operating Range — Full Load in Extreme Conditions
The PEDS is rated for full-load operation from −40°C to +70°C. The enclosure is manufactured from Italian-import UL 94 V-0 flame-retardant material that will not deform below 300°C, significantly outperforming standard domestic-grade plastics that begin to deform around 245°C. This matters on south-facing roof installations in summer where enclosures can reach high temperatures from solar heating.
−40 to +70°CUL 94 V-0 material300°C deformation point
World’s First Isolator to Pass IEC 60947-3 (ed.3.2):2015 — Full Certification Stack
Projoy was the first company in China to pass IEC 60947-3 (ed.3.2):2015 — the updated DC isolator standard which added critical current testing, thermal cycling, moisture resistance tests and higher pulse voltage requirements compared to the previous edition. The PEDS series carries TUV, CE, CB, SAA, UL and UKCA certifications. UKCA certification (obtained November 2022) covers the full PEDS, PEDSH and PEDSC range, confirming compliance with UK market access requirements post-Brexit.
IEC 60947-3 ed.3.2:2015TUV + CE + CB + SAA + ULUKCA certifiedUK-market compliant
Single-Channel Contact Design for 40–55A — Better Stability than Stacked Poles
For the higher-current PEDS variants (40A and 55A), Projoy uses a single-channel two-stage contact design to reach 1500V / 40–55A, rather than stacking 3–4 separate poles in series as most competitors do. Stacked-pole designs require all contacts to switch with precisely equal timing and gap; manufacturing variation means they rarely do, reducing actual breaking performance. The single-channel design is more consistent and more stable, and is the only Chinese DC isolator product to hold TUV certificates for 40A and 55A ratings individually.
Single-channel 40–55ABetter than stacked polesOnly Chinese 40A/55A TUV cert
Magnetic arc extinguishing + gate arc extinguishing (dual system)
Contact Design
Self-cleaning wiping contacts
Contact Design (40–55A)
Single-channel two-stage (not stacked poles)
Physical and Environmental
IP Rating (Enclosure Series)
IP66 (dustproof, high-pressure water-jet proof)
Flame Retardant — Body
UL 94 V-0 (Italian-import material, deformation point >300°C)
Flame Retardant — Handle
UL 94 V-2
Operating Temperature
−40°C to +70°C (full load)
Handle Positions
3 positions: ON / intermediate / OFF (lockable)
Lockable
Yes — padlock in OFF position
Mounting Options (PEDS Series)
Enclosure (PEDS-EL)
IP66 standalone enclosure, wall-mount
Single-Hole Mount (PEDS-HM)
Panel or enclosure back-plate, single hole
Panel Mount (PEDS-PM)
Bolted to panel surface
DIN Rail / Distribution Board
Snap-fit to 35mm DIN rail
Door Clutch
Handle on door, mechanism to chassis
Standards and Certifications
Primary Standard
IEC/EN 60947-3:2009+A1+A2 (ed.3.2:2015 for 40–55A)
Additional Standards
AS 60947.3, UL508i, GB/T14048.3
Certifications
TUV, CE, CB, SAA, UL, UKCA
UKCA Coverage
Full PEDS, PEDSH and PEDSC series — UK market compliant
ISO
ISO 9001 (quality), ISO 14001 (environmental)
Manufacturer
Manufacturer
Projoy Electric Co., Ltd.
Location
Suzhou, China (founded 2011)
Market Position
Used by the majority of China’s mainstream PV inverter manufacturers
Frequently Asked Questions
Do I need a DC isolator if my inverter already has a built-in DC switch?
Yes. The inverter’s internal DC switch isolates the inverter from the PV cables — but it is inside the inverter enclosure and is not designed to be the primary means of external isolation for maintenance work. BS 7671 (18th Edition) requires an externally accessible means of isolation on the DC side of every grid-connected PV system, rated as an isolator-disconnector to IEC/EN 60947-3. The PEDS fulfils this requirement. It should be mounted close to the inverter, clearly labelled as a PV DC isolator, and accessible without opening the inverter.
What is the difference between an isolator and a circuit breaker?
A DC isolator (isolator-disconnector) is designed to disconnect a de-energised or lightly loaded circuit safely. It provides a visible, lockable means of isolation so that maintenance can be carried out safely, but it is not designed to interrupt sustained fault current. A DC MCB or circuit breaker (such as the Projoy PEBS-L or PEBS-H) is designed to interrupt overload and short-circuit fault current automatically. For a PV installation, you typically need both: an isolator for safe manual isolation and a circuit breaker or fuse for overcurrent protection of the DC cable.
How do I select the right current rating?
Multiply the panel string short-circuit current (Isc, from the panel datasheet) by 1.25 (the IEC safety factor for PV). Example: panels with Isc = 12A → 12 × 1.25 = 15A → use a 16A isolator. For panels with Isc = 14A: 14 × 1.25 = 17.5A → use 25A. Always check the inverter manufacturer’s documentation for their recommended DC isolator current rating for the specific inverter model.
Should I use 2-pole or 4-pole?
Use 2-pole (2P) for single-string / single-MPPT inverters (one string of panels). Use 4-pole (4P) for dual-MPPT inverters with two independent strings. Most modern residential string inverters from 3–8 kW have two MPPTs and require a 4-pole isolator. Check the inverter datasheet for MPPT count and the number of DC input pairs.
Is the PEDS suitable for use in the UK after Brexit?
Yes. Projoy obtained UKCA certification for the full PEDS, PEDSH and PEDSC series in November 2022. UKCA is the UK conformity assessed mark that replaced CE marking for products placed on the UK market (England, Wales, Scotland) after 1 January 2023. The PEDS carries both CE and UKCA marks, confirming compliance with UK market access requirements.
Related Products
Projoy PEAS AC Isolator (20–40A)
AC-side isolation at the inverter output — also required by BS 7671
Projoy PEFS-EL Firefighter Safety Switch
String-level rapid shutdown — disconnects panels from inverter DC run
Projoy Battery Isolator PEBS-L with Enclosure
DC MCB for battery–inverter circuit protection
Projoy DC Surge Protector (PESP)
Surge protection device for DC PV string circuits
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