Business Energy Switching UK: The 17-Day Process and What Can Go Wrong

TL;DR

The standard business energy switch takes 17 working days from the date a contract is signed with the gaining supplier. The process can be blocked by outstanding debt, registration disputes, or MPAN mismatches. Erroneous transfers - switches that should not have happened - are covered by the Erroneous Transfer Customer Charter. Knowing the most common failure points prevents avoidable delays and losses.

Last reviewed: 12 May 2026

Switching a business energy supplier is a regulated industry process governed by the Balancing and Settlement Code (BSC) for electricity and the equivalent Uniform Network Code (UNC) for gas. It is not simply a commercial transaction between two parties. It involves a structured sequence of data exchanges between the gaining supplier, the losing supplier, the meter point administration systems, and (for electricity) Elexon's central settlement infrastructure. Understanding the stages, the timeline, and the reasons a switch can fail or be delayed allows businesses to manage the process with realistic expectations and respond effectively when problems arise.

The 17-working-day switch timeline

Following Ofgem's Faster Switching programme, which completed its electricity implementation in 2021 and its gas implementation subsequently, the standard timeline for a non-domestic electricity switch is 17 working days from the date the gaining supplier registers the change of supply in the central systems. The process has several distinct stages:

Contract signature: the customer signs a new supply contract with the gaining supplier. This triggers the supplier's obligation to register the switch in the industry systems.
Objection period: the losing supplier has a defined period to raise an objection to the switch - typically for reasons of outstanding debt or a valid notice period in the existing contract. If no objection is raised, the switch proceeds.
Switch date confirmation: the gaining supplier confirms the supply transfer date to the customer. This is the date from which the new supplier's contract applies and consumption is billed by the new supplier.
Meter reading: a meter reading is taken on or around the switch date to establish the boundary between the losing supplier's billing period and the gaining supplier's billing period.
Final bill from losing supplier: the losing supplier issues a final bill covering consumption up to the switch date. The gaining supplier begins billing from the switch date.

The 17-working-day timeline runs from step 1 to step 3. The final bill from the losing supplier may take a further period to arrive after the switch date, depending on whether the closing meter read is actual or estimated.

The roles of gaining supplier and losing supplier

In the switching process, the gaining supplier (the new supplier the customer has contracted with) is the active party. It initiates the industry transfer request, manages the objection period, and takes on responsibility for the customer's supply from the switch date. The losing supplier (the existing supplier) is the reactive party. It can object to the switch within the objection window, but if it does not raise a valid objection, it has no further ability to block the transfer.

The gaining supplier is responsible for ensuring the MPAN (for electricity) or MPRN (for gas) details are accurate. An error in the meter point identification at this stage is one of the most common causes of a blocked or erroneous switch, and it is the gaining supplier's obligation to verify the details before submitting the transfer request.

Blocked switches: the most common causes

A switch can be blocked - returned to the gaining supplier with a rejection - for several reasons. The most common are:

Outstanding debt block: under the industry rules, a losing supplier can block a switch where the customer has an outstanding debt on the account. The debt threshold and the process for raising a debt block are set out in the relevant industry codes. A business that has an overdue balance with its current supplier should resolve it before attempting to switch, as a debt block can delay the transfer by weeks.
Registration dispute: if there is a discrepancy between the customer's account details and the details registered on the central meter point administration system, the transfer request may be rejected. Common discrepancies include differences in the registered site address, meter serial number, or supply type.
MPAN mismatch: providing an incorrect MPAN to the gaining supplier - for example, transposing two digits in the 21-digit number - will cause the transfer request to fail. Businesses should verify their MPAN from a recent bill or directly with the current supplier before signing a new contract.
Existing contractual notice period: where a fixed-term contract requires notice before the customer can switch and the notice period has not been served, the losing supplier can raise an objection. This is a valid objection under the industry rules and must be resolved either by serving the required notice or by negotiating an early exit with the losing supplier.
Meter in dispute: if the meter point is subject to an ongoing billing or ownership dispute, the switch may be held pending resolution.

Erroneous transfers and the customer charter

An erroneous transfer occurs when a supply is transferred to a new supplier when it should not have been - most commonly because the wrong MPAN was submitted, a neighbouring premises was incorrectly switched, or the switch was processed without the customer's authority. Erroneous transfers can result in a customer receiving bills from a supplier they never contracted with, or finding that a supply they did not intend to move has changed hands.

The Erroneous Transfer Customer Charter is an industry commitment by licensed suppliers that sets out the process for resolving erroneous transfers. Under the charter, when an erroneous transfer is identified:

The supplier that erroneously took over the supply must acknowledge the erroneous transfer within a defined timeframe
The customer must be returned to the original supplier (or a supplier of their choice) as quickly as possible
Any charges raised by the erroneous supplier must be cancelled
The original supplier must restore the customer's original contract terms where possible

Erroneous transfers are reported to Ofgem as part of the licence condition compliance monitoring process. A business that discovers it has been erroneously transferred should contact both the erroneous supplier and its original supplier immediately, in writing, citing the Erroneous Transfer Customer Charter and requesting resolution within the charter timescales.

The Energy Switching Guarantee

The Energy Switching Guarantee is a voluntary commitment by participating suppliers to handle switches within specified timeframes and to remediate failures within a defined period. The guarantee applies to switches that meet its eligibility criteria and is administered by the Energy Switch Guarantee scheme. Participation is voluntary for suppliers, and not all licensed suppliers have signed up to the guarantee.

For businesses switching between participating suppliers, the guarantee provides a defined standard of service and a route to compensation if the switch is not completed within the guaranteed period. Businesses should check whether both their current and prospective supplier are members of the scheme before relying on its protections.

What happens to billing during the switch period

During the 17-working-day switch period, the losing supplier continues to supply and bill the customer on the existing contract terms. The new contract with the gaining supplier takes effect only from the confirmed switch date. A business that has signed a new contract at a lower rate should not expect the saving to apply from the day of signing - it applies from the switch date, which may be up to four weeks later.

If the meter reading on the switch date is estimated rather than actual, there is a risk of billing discrepancy at the boundary. Both the losing supplier's final bill and the gaining supplier's opening bill should be checked against any available actual meter reading for the switch date. If the estimated reading is significantly inaccurate, a formal meter read dispute can be raised with the relevant supplier.

Frequently asked questions

Editorial disclaimer: This article describes the business energy switching process as governed by industry codes and Ofgem licence conditions. It does not constitute commercial or legal advice for any specific switching scenario.

Can a supplier refuse to release a business customer who wants to switch?

A losing supplier can only block a switch on valid grounds under the industry codes: outstanding debt, a contractual notice period that has not been served, or a legitimate registration discrepancy. It cannot block a switch simply because it does not want to lose the customer. A supplier that attempts to block a switch without valid grounds is in breach of its licence conditions and the matter can be escalated to Ofgem or, for microbusiness customers, to the Energy Ombudsman.

What is the difference between a switch and a change of tenancy?

A switch is a change of supplier at the same premises by the same customer. A change of tenancy is a change of the responsible customer at the same premises - typically when a business takes on new premises or vacates existing ones. The two processes are governed by different industry procedures. In a change of tenancy, the incoming customer may be placed on a deemed contract from the date they take on responsibility for the premises, while a switch involves a new supply contract between an existing customer and a new supplier. Both processes use the MPAN as the primary identifier but follow different industry flows.

How does the switch process work for a multi-site business?

Each meter point (MPAN for electricity, MPRN for gas) is switched independently through the industry process. A business with 10 supply points switching to a new supplier must initiate 10 separate transfer requests, each with its own 17-working-day timeline. In practice, many suppliers and brokers manage multi-site switches through a coordinated submission to align all switch dates, but each individual transfer remains a separate industry process. Businesses should confirm with the gaining supplier how multi-site switches will be coordinated and what happens if one site encounters a blocking issue.

What should a business do if the losing supplier sends a final bill that appears inaccurate?

The business should compare the closing meter reading on the final bill against any available actual reading taken on or around the switch date. If the closing read appears to be estimated and is significantly different from the actual reading, a formal billing dispute should be raised with the losing supplier in writing, citing the specific meter reading discrepancy. The losing supplier is required under its licence conditions to investigate and respond to billing disputes. If the dispute is not resolved satisfactorily, escalation to the Energy Ombudsman is available for microbusiness customers.

Is there compensation if a switch takes longer than 17 working days?

For businesses switching between suppliers that are members of the Energy Switching Guarantee, compensation may be available if the switch is not completed within the guaranteed period and the delay is attributable to the supplier rather than to external factors such as a debt block or registration dispute. For switches not covered by the guarantee, there is no automatic statutory compensation for delayed switches, though a business that suffers a quantifiable loss from a delay caused by the supplier's error can raise a complaint and claim through the ombudsman process (for microbusiness customers) or through commercial negotiation.

How we verified this

This article draws on Elexon's Balancing and Settlement Code documentation at elexon.co.uk, Ofgem's guidance on the faster switching programme and supply licence conditions at ofgem.gov.uk, and the Erroneous Transfer Customer Charter as published by the energy industry. References to the 17-working-day timeline reflect Ofgem's published faster switching implementation documents. No aggregator, broker, or comparison site content was used as a primary source.

Sources

For more on what can delay a switch due to contract exit obligations, see business-energy-exit-fees-uk. For information on what happens when a supplier fails during or after a switch, see solr-supplier-of-last-resort-business.