Submitting Reads

Learn how to submit meter readings, understand rejections and carry out other related tasks.

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    How to submit a meter reading

    How you submit a meter reading – and how often – depends on the ‘class’ your meter is assigned to. We call this its product class.

    Use the table at the end of this section to identify your product class.

    The submission process

    If a meter is Class 2, 3 or 4, the Shipper needs to send their reading in an electronic file through our Information Exchange (IX).

    Use the correct file type.

    • For Class 2 meters, use the Unbundled Daily Read (UDR) file.
    • For Class 3 meters, use the Unbundled Batch Read (UBR) file.
    • For Class 4 meters, use the Unbundled Meter Read (UMR) file.

    All the file hierarchies and formats are in the UK Link Documentation Library secure area.

    If you can’t access the secure area, please visit Accessing secure documents.

    The links in the table below take you to the file hierarchy documents in the UK Link secure area. The documents explain which individual records make up a file.

    For example, the .UMR file of Class 4 meter readings will consist of a Header Record, a Trailer Record (or “footer”) and multiple individual U01 records for each meter reading.

    Understand your product class

    (Product) class Qualifying sites  How often you need to submit reads Reads provided by  File type to submit reads
    1 All sites with a rolling annual quantity (AQ) over 58.6m kWh  Daily Daily Metered Service Provider (DMSP)  .DLC 
    2 Any site with rolling AQ below 58.6m kWh AND daily read equipment or capability (eg automated meter reading (AMR) device, smart meter)  Daily Shipper .UDR  
    3 Any site with rolling AQ below 58.6m kWh AND daily read equipment or capability (eg AMR device, smart meter)  Batches of daily reads – submitted at least weekly Shipper .UBR 
    4 Any site with rolling AQ below 58.6m kWh  Monthly, if AQ is over 293,000 kWh, OR if an AMR device is fitted or a smart meter is active. Otherwise, you can choose between monthly or annually  Shipper .UMR 


    How often should you submit reads?

    The Uniform Network Code (UNC) shows how often meter reads should be supplied – and outlines performance targets.

    Class  Read frequency  Read performance target  UNC reference 
    1 Daily  100% by 11:00 on D*+1  M5.6.1 
    2 Daily  97.5% by close of D+1  M5.7.4 
    3 Daily in batches  90% of required reads each month   M5.8.5 
    4 Monthly  90% of sites to be read each month  M5.9.7 
    4 Non-monthly  At least one read a year  M5.9.9 

    * D refers to the Gas Day, which runs from 5am to 4:59am the following day. So meter readings for Gas Day October 1 for Class 1 must be submitted by 11am on October 2

    Shippers’ performance is reported to the Performance Assurance Committee (PAC) each month.

    If PAC is concerned about a Shipper’s performance, they ask us to contact them.

    We explain any issues and ask the Shipper to create a plan to get back to UNC levels.

    Gas meter readings help the gas industry run smoothly and are fundamental to many processes.

    Regular, accurate meter readings:

    • ensure a site’s Annual Quantity (AQ) remains up to date

    • inform accurate AQs – which help us allocate the right amount of gas to Non-Daily Metered Sites, minimising Unidentified Gas swings

    • allow us to regularly settle out, or reconcile, a site in our central systems. This means we can quickly correct unusual usage patterns and ensure customers are billed correctly

    • help us calculate a winter consumption, which also helps accurate daily gas allocation

    • reduce the risk of disputes or incorrect billing to consumers when we do need to estimate a meter reading, as the estimation period is much shorter

    Timelines for submitting opening readings

    When a Shipper takes on a meter point, they need to send an opening reading.

    These are sometimes called change of Shipper readings or transfer readings.

    When a reading isn’t received, we create an estimate based on:

    • the last reading
    • the meter set-up details held on central systems
    • the AQ
    • weather-corrected daily allocation profiles

    Opening readings are submitted in the same files as U01 records. If you can’t access this link, please visit Accessing secure documents.

    The timelines for taking and sending opening reads depend on your product class.

    (Product) class  When to take the read  Deadline for submission 
    1 D – your registration date  5 calendar days after D 
    2 D – your registration date  5 calendar days after D 
    3 D – your registration date  10 business days after D 
    4 5 days before D to 5 days after D  10 business days after D 


    Understanding read rejections

    We run a series of checks when meter readings are submitted.

    These are laid out in the UNC’s Validation Rules.

    If any rules aren’t met, readings are rejected. You’ll receive a rejection reason code from us.

    All codes and explanations are included in the UK Link Documentation Library secure area.

    Shipper rejection codes

    If you can’t access the secure area, please visit Accessing secure documents.

    View our e-learning module on Read Rejects for more details.

    The checks we make

    For basic checks, we make sure:

    • the Shipper who sent the reading is the registered Shipper
    • the right file format has been submitted
    • the submission matches the meter’s serial number

    We also do the following in-depth verifications.

    Energy tolerance checks

    We compare the amount of energy from the reading against the site’s System Offtake Quantity (SOQ) – or its annual quantity (AQ) divided by 365. SOQ refers to the maximum amount of gas the site’s allowed to use.

    If the result falls outside agreed levels of tolerance, we reject the read.

    The goal is to stop very large consumptions being created by incorrect reads.

    The Uniform Network Code (UNC) Validation Rules set out the checks that we must perform.

    Section 8 sets out the tolerances, which are intended to stop very large consumptions being created by incorrect reads. The Shipper needs to perform the same consumption checks before submitting their reading.

    • If the reading has an energy figure between the inner and outer tolerances, the read will be rejected. This is unless the Shipper sets the “TOLERANCE_OVERRIDE_FLAG” in the U01 record to “Y”. This flag means “Yes, I have validated the energy figure and it’s high but correct”.

    • As an extra safeguard against erroneous large consumptions, if the calculated energy figure is below the inner tolerance, but the “TOLERANCE_OVERRIDE_FLAG” is “Y”, the record will be rejected. This scenario suggests that the Shipper has a different view of the site or equipment set-up, which needs investigating before the read is accepted. A rejected reading can be resubmitted with a different Tolerance Flag.

    Each rejection record will include a rejection reason code. The read rejection can be found in the Shipper Rejection Codes document, which you can find in the UK Link document repository.

    Frequency and age of submission

    We also have rules on how often meter readings can be sent.

    • If a reading is sent in too soon, it’ll be rejected with reason code MRE00490.
    • If the age of a reading is outside the agreed limit, it’ll be rejected with reason code MRE00489.

    Rules for Classes 3 and 4 are found in this table.

    Class and meter read frequency   Expected frequency of read submission  Minimum gap since last accepted read  Maximum age of readings 
    Class 3   Daily in batches, expected to be submitted weekly  1 calendar day  10 calendar days 
    Class 4 monthly  Monthly   7 calendar days  25 business days 
    Class 4 annual, AQ >73,200 kWh  Annual  14 calendar days  25 business days 
    Class 4 annual   Annual  25 calendar days  25 business days 

    How to replace a meter reading

    To replace a meter reading:

    • use the same file and record type as the original reading
    • add a METER_READING_REASON of ‘R’ (this stands for replacement)


    More about reads

    Explore our reads e-learning courses in the learning hub. 

    Visit e-learning

    Need more help?

    If you have a query about reads, please raise a support request.


    Raise a support request