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P432: What it is and how it affects you.

Elexon, the electricity industry regulator in the UK, has introduced a new change called P432.

It means that from 1st April 2024, all new Current Transformer (CT) Advanced meters must be treated as Half Hourly (HH) for settlement and billing.

So as a business, if you have any Non-Half Hourly (NHH) CT meters, they will need to be updated to work as HH by March 2026.

Here we’ll explain more about P432, why it’s happening and how it will impact you, plus answer some Frequently Asked Questions.

What is P432?

P432 is a modification by Elexon that will ensure all Current Transformer (CT) Advanced meters are settled Half Hourly.

We’re experts in the change of measurement class.

The last time the industry saw a change like this was in 2017, known as P272.

This required a Change of Measurement Class from NHH data collection for profile class 05-08 to HH data collection.

We were integral in the smooth delivery of P272 for our customers, so we’re well-positioned to support you for P432.

We will take you through any necessary process and administration changes to cover the new HH Meter operator and data services and the physical switch over to HH data collection.

If you’d like to know more contact us anytime

Illustration of an electricity meter showing the meter read

Why is P432 happening?

CT Advanced Meters present a disproportionate risk in migration to MHHS and that is why they are being targeted now.

Without the change of NHH CT meters to HH ahead of the wider migration of meters to MHHS, there’s a risk that there will be insufficient time for Customers, Suppliers and their Agents – including Stark – to address any issues.

P432 Timeframe

blue lightening bolt

1st April 2024

All new CT connections must be HH settled from this date

15th April 2024

P432 starts for all NHH CT meters

March 2026

All NHH CT meters must be changed to HH

What meters are affected by P432?

If you have any Non-Half Hourly CT meters, they will need to undergo a Change of Measurement Class to Half Hourly by March 2026.

In addition, any new CT connections from 1st April 2024 should be HH settled.

There are an estimated 50,000 CT Meters accounting for approximately 800 – 1,500 GWh per year which will be affected by P432.

They will all move to HH Settlement using the Change of Measurement (CoMC) process.

How do we identify NHH CT meters?

We use the information sent by the Meter Operator to identify if your meter is a NHH CT meter.

Sometimes, this information can be incomplete or unclear on certain details, so we may likely have to do some digging.

  • If you use Stark Connect for your metering services, and we’ve adopted your existing NHH meters then we will look at the information the previous meter operator provided to us.
  • If we’ve installed new NHH CT meters for you, then we’ll be able to identify these.

That’s why P432 is happening now, ahead of MHHS, so Stark and other agents in the market can have the time needed to properly identify NHH CT meters.

Will my meter need to be exchanged to comply with P432?

Not necessarily.

Most meters can be remotely reconfigured to start collecting as HH instead of NHH.

We already collect HH data from most of our NHH meters so it should be an easy change.

Of course, each meter is set up differently, and our teams will be able to advise you on a case-by-case basis.

project delivery illustration showing a man and a woman working on laptops


P432 is an Elexon change that will ensure that all NHH CT meters are HH and ready for the shift to Market-wide Half Hourly Settlement.

The plan is to start P432 now to allow time for any issues to be addressed so MHHS is not delayed.

If you have any questions on P432, contact us today.

Contact us


What is a CT meter?

A CT Meter is a Current Transformer meter.

It’s an electricity meter which uses a Current Transformer as part of the mechanism for measuring the electric current.

This is different to a Whole Current meter (WC) where the electricity supply passes through the Meter itself. 

Most HH supplies use a CT meter. 

How do I know if I have NHH CT meter which will be impacted by P432?

Contact us where Stark Connect is your Meter Operator or alternatively contact your Supplier.

If I have NHH CT meters how will P432 impact my business?

As a business or end consumer, Stark will start to collect HH data from the meter and you can access it on Stark ID.

It means you will be able to access granular data for your supplies, target waste and implement energy management techniques with more confidence and precision than before.

Importantly, your supplier will have HH data sent to them for more accurate billing instead of basing it on NHH profiles.

Will my supply capacity costs be affected once I move to HH under P432?

Ofgem has advised that once customers under P432 have 12 months of recorded HH data, their Maximum Import Capacity can be calculated by Suppliers. Then any charges outside of the agreed capacity could be applied.

Ofgem says: “These charges are intended to encourage consumers with high usage meter points to remain within their reported maximum required capacity. Additionally, this cost is charged to energy suppliers who can choose whether or not to pass this charge onto consumers.” You can read the whole document here.

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