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This project ended in Jan 2019 and is now closed.Dismiss

Assessment & Testing of Alternative Cut-outs

Network operators
  • UK Power Networks
  • Northern Powergrid
  • Scottish & Southern Energy Networks
  • Scottish Power Energy Networks
  • Western Power Distribution
Funding mechanismNetwork Innovation Allowance
DurationNov 2017 - Jan 2019
Project expenditure£800K
Research areaLow Voltage and 11kV networks


The objectives of the project can be summarised as follows:

  • Identify alternative cut out equipment used outside of GB and prove that they are suitable for replacing in service cut-outs.
  • Identify novel arrangements and practices from DNOs outside of GB and assess whether or not they can negate some of the known problems that existing cut-outs in GB have.
  • Generate and disseminate enough learning to drive more informed inspection, maintenance and replacement cut-out regimes within each GB DNO.
  • Generate and disseminate enough learning to influence the BS 7657 and the ENA engineering recommendation for inspecting cut-outs.



Each Low Voltage (LV) customer is connected to the distribution network by fused cut-out equipment normally (but not always) located within the customer’s property or in a meter box. This cut-out equipment belongs to the Distribution Network Operator (DNO) and provides the interface between the DNO and the Meter Operator (MOP). The fuse fitted in the cut-out equipment provides a means of disconnecting the customer’s wiring in the event of a fault occurring on the wiring within the property.

Both the DNO and MOP have the authority to connect/disconnect wiring to the cut-out equipment and seal this equipment to prevent unauthorised interference. Only the DNO has authority to replace a blown fuse.

Historically DNOs have not separately inspected cut-out equipment for defects themselves, but do currently have a number of different measures in place to effectively manage these assets, such as visits from meter operators to periodically replace meters.

Cut-out equipment in customers’ premises can become damaged which could result in live conductors becoming exposed or cause current to leak to earth. These conditions are potential hazards to the occupants of the premises if left unresolved. It is also possible for cut-out equipment to overheat under certain conditions and this has been identified as a possible cause of fires in customers’ premises. Similar reliability issues of cut-out equipment have been reported by DNOs in the past.

The UK Government is currently supporting the mass roll out of Smart Meters. These Smart Meters will have Automatic Meter Reading (AMR) functionality, which will enable the remote communication of meter readings to the supplier, negating the need for them to visit individual premises to obtain meter readings. This means the regular inspections by MOPs will no longer take place increasing the risk of a potential cut-out failure being detected.


This project will look at alternative cut-out equipment used by network operators outside the UK and assess the suitability of these as a potential replacement for existing equipment. This aims to negate the issues that have been highlighted by various DNOs and a number of external stakeholders. It will attempt to achieve this by comparing the new technologies against existing equipment used by GB DNOs under normal operating conditions, but also under any known failure modes.

The project will also consider potential novel arrangements of the currently used cut-out assemblies, as well as practices followed by utilities outside the UK with the aim of finding possible solutions to identified problems.