Your energy supplier sells you electricity, but it does not own the cables that bring it down Epping High Street or out to Coopersale and Theydon Bois. That job belongs to the distribution network operator, and it is the network operator, not the supplier, that has to know about a home battery. This guide covers who that is for a CM16 address, what the installer tells it, and what the network’s own outage record means for the power-cut question. For where a battery goes in Epping homes, see our guide to battery storage in Epping.
The short version: the operator is UK Power Networks, the forms are the installer’s job, and a standard battery does not keep the lights on when the network goes down.
The network under CM16
On UK Power Networks’ own licence-boundary data, the Epping town-centre point sits in its Eastern Power Networks area, the network that Eastern Electricity once ran across Essex. On NESO’s boundary maps, the edge of UK Power Networks’ London Power Networks area is about 3.8 km from that point, which is close enough that homes on the edge of town should not assume. UK Power Networks’ postcode area checker settles it for any address. Either way the company is the same and so are the rules; only the licence name, and the reliability figures quoted below, would change.
The 16 A line
Every inverter that can push power onto the network counts, and a battery has one, which is why fitting one in Epping means paperwork even when nothing changes on the roof. The industry rule G98 covers type-tested equipment up to and including 16 A per phase, 3.68 kW on an ordinary single-phase supply. Below that line, the installer notifies the network operator before commissioning or within 28 days after it. Above it, the rule is G99: an application has to be approved before any work starts.
The line is about the total, not the battery alone. DESNZ records about 2,348 solar PV installations of all sizes across Epping Forest district at the end of 2025, so many batteries here will join panels that are already up, and those panels count, and a battery added to them can tip a home that went in under G98 over the line. A single 4 kW inverter draws 17.39 A, so it is just over on its own. The size of the battery in kWh does not decide this; the inverter output does.
How UK Power Networks handles it
UK Power Networks says that for a house or small business up to 69 kVA whose supply can take the new equipment, the installer only needs to notify it within 28 days, and that only approved installers can use its Smart Connect system, which handles G98 and G99 forms for solar PV and battery storage. Above the G98 line, it says it automatically approves applications where the maximum export, after any export limitation, is under 5 kW. An export limit, set in the inverter, is one way a larger Epping system stays inside that figure.
Two more points from the same source. If the existing supply cannot take the extra load, UK Power Networks may need to upgrade it first, with cost and timing varying by project. If no upgrade is needed, there is nothing to pay it. The installer contacts it on your behalf.
How often the Eastern network goes off
Ofgem publishes reliability figures for each licence area. For Eastern Power Networks in 2024/25 it reports about 44.6 supply interruptions per 100 customers, planned and unplanned, and about 32.5 minutes lost per customer over the year, down from 46.2 and 35.6 in 2023/24. The figure for all 14 licence areas in Great Britain was 39.7 interruptions and 35.1 minutes. On our arithmetic, 44.6 per 100 means the average customer had fewer than one interruption that year. These are licence-area averages, not a figure for Epping, and Ofgem notes they are as reported before its final assessment.
What a battery does when the power goes
A standard grid-tied battery shuts down when the grid does, however full it is, so that it cannot feed power into cables engineers may be repairing. Any panels go off with it. In an Epping home on a standard installation, a power cut looks exactly as it would without a battery.
Backup is possible, but it is a design choice made at the start: a backup-capable inverter or gateway, the switching that isolates the house from the grid, and a chosen list of circuits such as the fridge, lighting and broadband. That kit needs wall space beside the meter, which matters on the listed buildings that line both sides of Epping High Street, where anything fixed to the fabric is a conversation with the council first. Set Ofgem’s figures against what backup costs before deciding it is worth it, and if it matters, get it written into the quote.
Questions to ask before you sign
- Which licence area is my postcode in, and is this G98 or G99?
- What is the total inverter output, panels and battery together?
- Will you set an export limit, and what is it?
- Does my supply need upgrading, and who pays if it does?
- Is backup included, and which circuits does it cover?
Our explainer on how solar battery storage works covers the kit itself. If panels are part of the plan, our page on solar panels in Epping covers the roof, the green belt and the town’s conservation areas, and the Essex solar panels hub covers schemes across the county.
Sources: UK Power Networks, Licence Boundaries open dataset (modified 17 December 2024), Our history, Areas we cover, Smart Connect, and Solar and storage: cost, time and what’s involved (read 15 October 2026); NESO, GIS boundaries for GB DNO licence areas (3 May 2024); Energy Networks Association, EREC G98 Issue 2 (10 March 2025); DESNZ, Renewable electricity by local authority 2014 to 2025 (29 September 2026); Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025 and supplementary datafile (15 January 2026); Epping Forest District Council, Conservation areas.