P432 Explained
Mandate to upgrade all CT meters to half-hourly settlement
P432: What Your Business Needs to Know About Mandatory Half-Hourly CT Metering
By October 2026 all Non-Half-Hourly (NHH) Current Transformer (CT) Advanced electricity meters need to be transitioned to be half-hourly (HH). This is a precursor requirement to support a smooth roll-out for Market-Wide Half-Hourly Settlement and to give businesses better data quality for energy management insights.
Below, we explain what P432 is all about, and why it matters.
What is P432?
P432 is an industry change approved by Ofgem mandating that every CT Advanced electricity meter must be transitioned from Non-Half-Hourly (NHH) to Half-Hourly (HH).
In practice, rather than relying on estimates, daily, or monthly reads, each CT meter will now send us your energy data at 48 half-hourly intervals per day. The change applies to any new CT installation from 1 April 2024, and to all existing CT meters by October 2026.
The benefits for your business
More accurate invoices: Half-hourly data improves billing accuracy and reduces the need for estimates.
Granular insight: Half-hourly data pinpoints when energy use peaks—ideal for targeting efficiency projects.
Future proofing: HH settlement underpins the upcoming Market-Wide Half-Hourly Settlement (MHHS) and unlocks time-of-use tariffs.
Regulatory compliance: This is a mandatory requirement from Ofgem and will support us as we service your meter. Meeting P432 on time avoids emergency meter work and potential default rates.
How will UGP support you?
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Portfolio review – We’ll check every MPAN you hold and flag which meters need action.
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Upgrade plan – For each site, we’ll confirm whether a remote re-programme or physical exchange is required.
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Transparent costs – Before any change, we model the impact of HH data charges and network fees, so there are no surprises.
P432 implementation timeline
- 1 April 2024 – New CT meters must be registered as Half-Hourly.
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15 April 2024 – P432 obligations begin for existing CT meters.
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By October 2026 – All remaining NHH CT meters must be converted to HH settlement.
What do you need to do?
In most cases there’s no need for you to do anything, the update will be activated remotely and will not result in any changes to operational practices – your supply will not be disrupted. We’ll manage the transition and ensure ongoing compliance with industry requirements on your behalf.
If we’ve identified that a meter upgrade is necessary (such as ensuring your metering communications are working correctly) your appointed Meter Operator (Who services your metering on our behalf) may get in touch to arrange a site visit.
As P432 will bring future changes to charging structures and will likely affect your contract, a member of our team will also be in touch to explain what this means for you, and answer any questions you may have.
Questions?
If you have any questions about P432 or Market-Wide Half-Hourly Settlement, please reach out to our customer services team.