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Meter Serial Number

What is a Meter Serial Number (MSN)?

Every UK gas and electricity meter has a unique identifier baked in by the manufacturer called the Meter Serial Number, almost always shortened to MSN. It is the meter equipment’s own number, tracked through its lifetime regardless of who owns the building or pays the bill. The MSN is different to the MPAN or MPRN, which identify the supply point rather than the equipment. The supply identifiers stay the same when a meter is replaced; the MSN moves with the physical kit. For most UK businesses, the MSN is background data. It becomes briefly relevant during smart meter installs, suspected meter faults, and queries that need to point at a specific piece of equipment.

The MSN appears on both business electricity and business gas meters, and is one of the first things any engineer will ask for during a meter installation or exchange.

The MSN matters most at three specific moments. When a smart meter is installed and configured, when a meter is replaced or upgraded, and when a query needs to point at a specific piece of equipment (a faulty meter, a calibration check, a fault report). For most day-to-day purposes, the MPAN or MPRN is the identifier that matters more.

What the MSN actually identifies

The MSN is the meter manufacturer’s unique number for a specific physical meter.

• Assigned at the point of manufacture and printed on the meter casing or display.
• Unique to that one piece of equipment.
• Tracked through industry data systems alongside the supply point identifier (MPAN for electricity, MPRN for gas).
• Used to identify which specific meter is installed at which supply point.

If you take a photograph of your meter, the MSN is on the meter. The MPAN or MPRN is not on the meter itself; it is on the bill.

Where to find the MSN on your meter

On UK meters, the MSN appears in one of several places.

• Front label. Printed on a label on the front of the meter casing.
• Top or side of casing. Stamped into the metal or moulded into the plastic.
• Digital display. Some smart meters show the MSN on the screen when you cycle through the menu.
• Engineer commissioning sticker. Sometimes a sticker applied during installation.

If you cannot find it on the meter, your supplier holds it in their record system and can give it to you on request.

Typical MSN format

UK MSN format varies by manufacturer and meter type but follows common patterns.

• Typically 10 to 13 alphanumeric characters.
• Manufacturer prefix (e.g., L&G for Landis & Gyr, EML for EMLite, S for Siemens).
• Followed by a numeric sequence.
• Sometimes additional digits for year, batch, or factory.

The format itself is not standardised across manufacturers, but the MSN is always uniquely traceable through industry data systems regardless of format.

MSN vs MPAN vs MPRN

When a meter is replaced, the MSN changes (new physical kit) but the MPAN or MPRN stays the same (supply point is unchanged). When a supply is permanently disconnected, the MPAN or MPRN is retired but the MSN persists on the meter regardless.

When you need to provide the MSN

The MSN is requested in specific situations.

• Setting up a smart meter or configuring an in-home display unit.
• Reporting a suspected meter fault to the supplier or MOP/MAM.
• Calibration testing or accuracy check.
• Insurance or warranty claim where the meter equipment is the subject.
• Some technical industry queries that need to point at a specific piece of equipment.

For most everyday queries (billing questions, meter readings, change of tenancy), the MPAN or MPRN is the identifier the supplier needs, not the MSN.

What happens to the MSN when a meter is replaced

When a meter is swapped out (end of life, fault, smart meter upgrade).

1. The MOP or MAM removes the old meter.
2. The supplier’s record system retires the old MSN against the supply point.
3. The new meter is installed.
4. The new MSN is registered against the supply point.
5. The MPAN or MPRN identifying the supply point is unchanged.

The bills issued before and after the swap show different MSNs but the same MPAN or MPRN. The opening reading on the new meter is recorded so consumption can be split correctly between old and new equipment.

How the industry uses MSN

Industry data systems track MSN alongside the supply point identifier.

• UK gas. Xoserve maintains the MSN against each MPRN.
• UK electricity. The relevant MOP, DC/DA, and Supplier Hub Systems track MSN against each MPAN.
• Settlement uses the MSN to validate that the readings being used for billing are from the meter actually installed.
• Meter replacement transactions update the MSN record without disturbing the supply point.

MSN on smart meters

SMETS2 smart meters present the MSN slightly differently to traditional meters.

• The MSN may not be on a visible front label; it is sometimes only on the meter’s digital display when you navigate the menu.
• The smart meter’s in-home display (IHD) usually also shows the MSN somewhere in its information menu.
• The DCC (Data Communications Company) holds the MSN in the central smart meter register alongside the supply point identifier.

For smart meter installations, the engineer typically records the MSN as part of the commissioning process and provides it to the customer in the welcome pack.

MSN and Change of Tenancy

During a Change of Tenancy, the MSN matters less than the MPAN or MPRN.

• The COT process updates the customer details against the supply point (MPAN or MPRN), not against the MSN.
• The MSN is unchanged unless the meter itself is replaced.
• The outgoing and incoming occupiers see the same MSN on bills if the meter is not replaced during the move.

See Change of Tenancy for the broader process.

Practical implications for businesses

For UK business customers, the MSN is mostly background data. Three situations where it matters.

• Smart meter installation. The MSN is captured during commissioning. Keeping a record is useful for future fault reports.
• Suspected meter fault. A query about a faulty meter goes faster when the MSN is provided alongside the supply point identifier.
• Asset register. Larger organisations with an internal estate or facilities team often include MSN as part of their meter asset register for maintenance and contract management.

Related entries. MPAN, MPRN, Meter Operator (MOP), Meter Asset Manager (MAM), smart meter, Change of Tenancy, bill validation.

Common UK manufacturer prefixes

UK MSN format varies by manufacturer but typically starts with letters indicating who made the meter.

The prefix is part of the unique identifier and not a separate field. Industry data systems track the full MSN regardless of who made the meter.

Common MSN pitfalls

Recurring issues that catch UK businesses off guard.

• Reading the wrong number. The number on the meter face is the MSN, not the MPAN or MPRN. Supplier queries that need the supply identifier (most queries) need to come from the bill, not the meter.
• Lost commissioning record. Smart meter installs capture the MSN in the welcome pack. Losing the record makes future fault reports harder.
• Pre-replacement and post-replacement bills. A meter swap produces two MSNs on the account; reading patterns may briefly look unusual until the new meter has a few weeks of data.
• Mixing up MSN with meter readings. The MSN is a fixed identifier; the meter reading is the cumulative consumption. The two are completely different things on bills.

Frequently asked questions