BS EN 50549 grid-connection standards

BS EN 50549 is a series of standards for generating plants connected in parallel with a distribution network. It addresses the way generation behaves at the network interface. It is therefore different from BS EN 62109, which deals with the product safety of a PV inverter.

For a home solar or battery system, BS EN 50549 usually appears behind the G98 or G99 type-test evidence. It does not create a separate application route for the homeowner, and a certificate to BS EN 50549 alone is not permission to connect.

The relevant parts

As at 22 July 2026, BSI lists the following British editions as current:

Standard	Main scope
BS EN 50549-1:2019+A1:2023	Generating plants connected to a low-voltage distribution network, up to and including Type B
BS EN 50549-2:2019+A1:2023	Generating plants connected to a medium-voltage distribution network, up to and including Type B
BS EN 50549-10:2022	Tests for conformity assessment of generating units

Part 1 is the relevant base document for the low-voltage network used by a typical home. Part 2 concerns medium-voltage connections and is not simply a later or more demanding certificate for a domestic inverter. Part 10 supplies test methods; it does not replace the technical requirements in Part 1 or Part 2.

The part number and edition are important. A document saying only “EN 50549 compliant” is too imprecise to establish what was assessed.

What the series deals with

The detailed requirements depend on the plant type and connection, but the series covers grid-facing matters such as:

• permitted voltage and frequency operating ranges
• protection and response when network conditions move outside those ranges
• connection and reconnection behaviour
• active-power and reactive-power capability
• response to disturbances and changes in network frequency
• power-quality effects
• tests used to demonstrate conformity of a generating unit

These are behaviours of the generating plant at its connection to the distribution network. They are not a general measure of inverter quality, and they do not establish that the fixed wiring complies with BS 7671.

How it fits with G98 and G99

ENA Engineering Recommendations G98 and G99 set the Great Britain connection requirements and procedures used by DNOs.

G98 applies to fully type-tested micro-generating plant within its capacity limit. The ENA text requires the relevant part of the customer installation to conform to EN 50549-1 as applicable, together with G98’s additional or specific requirements.

G99 covers generation that does not use the G98 route. It contains its own categories, evidence and application procedures. A larger or more complex installation therefore cannot bypass G99 merely by presenting an EN 50549 certificate.

The relationship is best understood as three layers:

1. BS EN 50549 provides a common technical foundation for grid behaviour and testing.
2. G98 or G99 adds the Great Britain requirements and determines the connection route.
3. The DNO process applies the rules to the actual equipment and site.

The current G98 and G99 thresholds, aggregation rules and application timing are covered in their dedicated entries. Repeating them here would increase the chance of two pages drifting apart.

Batteries and hybrid systems

A battery inverter capable of operating in parallel with the public network is relevant to the connection assessment even if its main commercial purpose is to reduce imports rather than export electricity. The installer must account for the complete arrangement, including existing solar or other generation, rather than assessing each inverter as though it were the only one on the supply.

An export limitation scheme may change the power exported from the premises, but it does not automatically change the generating capacity used to select the connection procedure. Where G100 is used, its evidence is an additional layer rather than a substitute for G98, G99 or the relevant generating-unit evidence.

The exact model, rating, operating mode and approved control arrangement matter. A certificate for one product variant or grid profile should not be assumed to cover another.

Applicable standard and national requirements

For a domestic installation, the practical public check is normally the equipment record used by the ENA and the DNO, rather than buying a copy of BS EN 50549.

Confirm that:

• the manufacturer and exact model match the unit being installed
• the entry covers the relevant G98, G99 and, where applicable, G100 requirements
• ratings and firmware or configuration restrictions are observed
• all existing and proposed generation or storage has been included in the assessment
• the correct DNO application or notification route has been followed
• commissioning records preserve the approved protection and export settings

ENA now uses its Connect Direct platform for low-carbon-technology applications and equipment data. Platform names and interfaces can change, so the enduring requirement is to use the current ENA or DNO process and retain the resulting evidence.

What BS EN 50549 does not replace

It does not replace:

• BS EN 62109 evidence for inverter product safety
• BS 7671 design, installation and verification
• G98 or G99 type-test and procedural requirements
• G100 evidence for an export-limitation scheme
• the DNO’s acceptance or the G98 post-commissioning notification
• standards applying to the battery, PV modules or other products

A compliant installation needs the relevant evidence at each layer.

Related entries

• G98 notification pathway
• G99 application pathway
• G100 export limitation
• DNO notification for PV
• BS EN 62109 inverter safety standard
• Anti-islanding protection in solar inverters