UK Plug-in Solar IPS Explained: What a Compliant Kit Needs

The Plug-in Solar Device Interim Product Specification (IPS) sets the technical requirements that every plug-in solar kit sold in Great Britain must meet. It covers the electrical limits (800 VA, 3.5 A, 2,000 W of panels), the safety design of the plug and inverter, mounting and fire rules, product marking and instructions, and the tests that show the kit meets them. It does not require third-party certification. Instead, the company that places the kit on the market type tests it, keeps a technical file and registers it as compliant on the ENA Type Test Register before selling it.

Who the IPS applies to

The IPS covers single-phase plug-in solar devices for homes, rated up to 253 V AC, 50 Hz and 800 VA, installed and operated by ordinary persons and connected through a standard 13 A plug. A device consists of at least one PV module, a grid-following inverter, a lead fitted with a BS 1363 plug, and a mounting system.

It does not cover fixed PV systems under BS 7671 Section 712, building-integrated PV, plug-in batteries, plug-in solar with an integrated battery, or plug-in generation from anything other than solar panels.

Responsibility sits with whoever places the complete product on the market: the manufacturer, or a brand or importer selling the kit under its own name. The IPS words most duties as "the manufacturer shall", and the government response confirms that the IPS does not require certification by an independent third-party body.

The key numbers at a glance

Requirement	IPS v2 value	Clause
AC output	Max 800 VA and max 3.5 A	4.1, 6.4.1
PV module power	Total Pmax max 2,000 W	4.1
Professional assessment advice	Required above 960 W of modules	4.1, 8.3.2
Number of modules	Up to 4, no more than 2 in series	4.2.2
DC open-circuit voltage at inverter input	Max 120 V DC	4.2.2
Ingress protection	At least IP55 outdoors, better than IP44 indoors	5.4
Smooth DC residual current	Max 5 mA	5.7
Plug fuse	BS 1362 fuse, max 5 A, moulded non-rewireable plug	6.2.3.2
Disconnection after unplugging	Within 100 ms, plug pins below 34 V within 100 ms	6.2.3.3.3
Capacitor discharge	Capacitors above 100 nF to max 34 V within 1 s	6.2.3.3.3
Module fire performance	Outer layer equivalent to Euroclass B-s3, d2	6.3
Technical file	Kept at least 10 years after last manufacture	9.1

Clause 4: limits and device types

Power and current. The kit must not supply more than 800 VA or 3.5 A to the home. The inverter is tested at 0.94, 1.0 and 1.1 times the nominal 230 V, and the current at the point of connection must stay within 3.5 A under all test conditions. Table 1 of the type tests also checks the current at reduced mains voltage (about 0.85 Un).

Panel power. The modules may total up to 2,000 W. Above 960 W, the manufacturer must advise customers to consider a professional assessment of their electrical installation first. The IPS notes that this threshold reflects the principle in the German plug-in standard DIN VDE V 0126-95.

Device types. The IPS recognises one-component devices (a module with an integrated inverter), two-component kits (one module plus an inverter) and multi-component kits (up to four modules and one inverter). Multiple modules are connected through individual cables and connectors supplied by the manufacturer. No more than two modules may be in series, and the open-circuit voltage at the inverter input must not exceed 120 V DC to limit the risk of DC arcing.

Protection class. The kit must be Class I or Class II under BS EN 61140.

Clause 5: safety of the complete kit

These requirements apply to the whole assembly, not only to individual parts.

Overvoltage and EMC. The kit must be designed for at least overvoltage category II. EMC immunity must meet BS EN IEC 61000-6-1 and emissions BS EN IEC 61000-6-3, tested at maximum power.
Ingress protection. Outdoor components and connections must be at least IP55, and indoor-only components better than IP44. If individual parts are below IP55, the assembly as a whole must still achieve it.
Mounting system. A mounting system must be supplied with the kit. The manufacturer must specify it in detail and provide a structural analysis for wind and snow loads under UK conditions (BS EN 1991-1-3 and 1991-1-4 with the UK National Annexes and PD 6688-1-4). Fixing with cable ties, rope, string, adhesive tape, bungee cords or straps alone is not allowed. Minimum clearances for ventilation must be stated.
Corrosion and weathering. Materials must resist corrosion, avoid galvanic corrosion between metals and resist UV. Kits for marine or agricultural environments need salt mist (BS EN 61701) and ammonia (BS EN 62716) testing; otherwise the documentation must say the kit is not suitable there.
Electric shock. Live parts must not be accessible before, during or after installation.
RCDs. The kit must not impair upstream residual current devices. Smooth DC residual current into the mains must stay at or below 5 mA, tested at maximum output.
Fire. Fire risk is assessed at system level. Installation is not permitted on ACM, MCM, HPL or timber cladding, on timber balconies, or on buildings under external wall or building safety remediation.

Clause 6: cables, plug, modules and inverter

Cables and DC connectors. Outdoor DC cables must meet BS EN 50618 or equivalent. DC connectors must meet BS EN 62852, be supplied with the cables, and be used only in matching pairs from the same product family. Adaptors must be pre-assembled by the manufacturer. Y-connectors are not allowed.

The plug. The lead must have a BS 1363-1 plug with partially insulated pins, moulded and non-rewireable, fitted with a BS 1362 fuse of no more than 5 A. Multi-way adaptors, travel adaptors, RCD adaptors and plug converters are not permitted.

Additional contact protection. The inverter isolates its output when it loses the grid. In case this primary protection fails, the plug needs an additional measure: either a mechanical solution (locking, covers, shutters) that prevents access to the pins until the output is disconnected, or an electromechanical solution that removes dangerous voltage from the contacts within 2 seconds, independently of the main anti-islanding function.

Anti-islanding and plug pins. After the plug is pulled, the inverter must stop power conversion quickly, discharge capacitors connected to the pins and isolate any remaining hazardous voltage. Under test, the inverter must disconnect within 100 ms and the voltage at the pins must fall below 34 V within 100 ms. Capacitors larger than 100 nF must discharge to 34 V or less within 1 s. This isolation must still work if the device has a fault, and safety-relevant software must meet BS EN 62109-1 Annex B.

AC connector on the inverter. If there is a detachable connector between the inverter and the lead, it must reach at least IP4XD when engaged for outdoor devices and IP2XB when not engaged. Any unused AC port, for example for parallel inverters, must be closed with a cap that can only be removed with a tool.

PV modules. Modules must meet BS EN IEC 61730-1 and -2, with the junction box to BS EN IEC 62790, cables to BS EN 50618 or IEC 62930 and connectors to BS EN 62852. They must be Class II unless SELV or PELV. The outer layer (usually the backsheet) must reach the equivalent of Euroclass B-s3, d2 under BS EN 13501-1. Modules must be removable from the mounting system without a professional tool.

Inverter. The inverter must meet BS EN IEC 62109-1 and -2 (and -3 for module-integrated electronics) and BS EN 62116 for islanding prevention, with environmental category "outdoor" and decisive voltage class DVC C for basic protection. It must have a status and fault display, on the device or in an app, with guidance for the user.

Clause 7: G98 and the ENA register

The kit must meet Engineering Recommendation G98 for connection to the low-voltage network in Great Britain. The manufacturer must type test it to G98, register it on the ENA Type Test Register (ENA Connect Direct) and obtain confirmation that it has been assessed as compliant before placing it on the market. Submitting an application does not count as compliance.

From design to sale under the IPS

Design to IPS v2limits, plug, mounting, fire
Type testson a representative kit, Table 1
Technical filereports and calculations, kept 10 years
ENA Type Test Registerlisted as compliant
On salewith routine tests on every unit

The order matters: the exact kit model must be listed as compliant on the register before it is placed on the market.

Clause 8: marking and instructions

Instructions must be in English. The product must be permanently marked with the manufacturer's name, postal and email address, model, serial number, mains voltage, frequency, highest continuous current, rated power, IP rating and protection class. It must also carry statements that only one inverter of up to 800 VA may be plugged in per household circuit, that notifying the distribution network operator (DNO) is mandatory (with a link to instructions), and that the product complies with the IPS. Components must be labelled as required by the Electrical Equipment (Safety) Regulations 2016. A durable label for the consumer unit must be supplied.

The plug (or a band near it) must show the one-device-per-circuit rule, the device's rated current, the ISO 7010 M002 "refer to instructions" sign and a warning against extension leads, multi-way adaptors and RCD adaptors.

The instructions have a long mandatory list. Points that are easy to overlook:

Permitted mounting types and maximum installation heights, based on UK wind and snow loads.
Prominent warnings on prohibited surfaces and remediation buildings, and that the kit must not be used with a battery storage system.
How to identify which sockets share a circuit, and that the kit goes on a socket circuit, not lighting or fixed equipment.
Advice to check for modern RCBO protection, and to test the RCBO periodically while the kit is producing.
A QR code to DNO guidance for registering and deregistering the device.
The user's responsibility for permissions from the landlord or freeholder, planning, insurance, escape routes and fire spread to neighbours.
Lightning protection separation distances, cable routing from outside to inside, and not disconnecting DC connectors under load.
Decommissioning and disposal under the WEEE Regulations.
The PV module data sheet to BS EN IEC 61730-1, and the inverter data sheet to BS EN 50524 with the G98 certificates.

Clause 9: type tests, technical file and routine tests

Type tests are carried out on a representative device and must cover every applicable clause. Table 1 of the IPS lists the minimum tests, from maximum apparent power and DC residual current to plug contact protection, module fire performance and a check that the documentation is complete. The type test report records the device, methods, measured values and the result.

The manufacturer keeps a technical file with test reports, calculations such as the structural loading analysis, and evidence of conformity with the referenced standards, for at least 10 years after the last unit of that type is made.

Every production unit then gets routine tests: correct assembly, packaging, marking and documentation, and correct operation of the disconnection function and capacitor discharge.

Frequently asked questions

Does the IPS require third-party certification?

No. The government response says the IPS does not require certification by an independent third-party body. Compliance rests on the manufacturer's type tests, technical file and declaration, and the kit must be registered as compliant on the ENA Type Test Register before sale. The plug itself must be approved by a notified body under the Plugs and Sockets etc. (Safety) Regulations 1994.

Is a microinverter on its own an IPS-compliant product?

No. The IPS applies to the complete plug-in solar device: modules, inverter, lead with plug, cables, connectors and mounting system. The complete kit is what is type tested and registered.

Can a kit built to the IPS include a battery?

No. Plug-in batteries and plug-in solar devices with an integrated battery are outside the scope of the IPS, and the instructions must warn against using the kit with a battery storage system.

What is the maximum panel power for a plug-in solar kit?

The sum of the module Pmax values may not exceed 2,000 W, with up to four modules and no more than two in series. Above 960 W, customers must be advised to consider a professional assessment of their installation.

How long must the technical file be kept?

At least 10 years after the last unit of the device type is made.

Is the IPS the final UK standard?

No. It is an interim specification. The government has said that work will begin on longer-term standards to replace it, but has not given a date. Check GOV.UK for the current version before designing or listing a kit.

How VaySunic can help

VaySunic develops microinverters and complete plug-in solar kits in-house, at its R&D and manufacturing centre in China, with European headquarters in Germany. For UK brands and retailers that want to sell a kit under their own name, our OEM / ODM programme covers the kit hardware, firmware, labelling and documentation under your brand, as well as the app and cloud. Distributors can find details in our distributor programme and see our standard plug-in solar kits. The registration status of a kit depends on the exact model, so contact us for the current UK status of any kit you plan to sell.