Hazard Cables - Developed and maintained by the NFCC - National Operational Guidance

Hazard
            Cables

Developed and maintained by the NFCC

Contents
Hazard - Cables ........................................................................................................................................... 3
      Control measure - Situational awareness: Cables .......................................................................... 4
      Control measure - Isolate utilities ...................................................................................................... 5
      Control measure - Remove or secure internal fixings or cables ................................................... 6
      Control measure - Firefighter emergency arrangements: Cables ................................................ 7

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Hazard - Cables

Hazard Knowledge

Cabling, including mechanical, electrical and data cables, is used extensively in buildings, with an
increased reliance on surface-mounted conduit and trunking during installation.

Electrical upgrades and retrofitting additional electrical sockets, light fittings, security/fire alarms
and data cables may mean that lightweight cable fixings are more common in older buildings.
Cabling may also be concealed above suspended ceilings, with little or no fixing. Suspended ceilings
may also become distorted or fail at relatively low temperatures.

Plastic conduit or trunking that is surface-mounted on ceilings and walls will fail at relatively low
temperatures (more than 100◦C). Thin section aluminium trunking may also fail. Cabling and cable
installation in buildings present hazards including:

      Electrocution
      Entanglement
      Breaching of fire compartmentation
      Hazardous products of combustion

When the conduit or trunking fails, cables may be released. Because they can fail at relatively low
temperatures, cables may drop some distance from the seat of fire and may hang down,
presenting a risk of entanglement or electrocution. Hanging cables pose a significant hazard for
firefighters and have contributed to firefighter deaths in the past. This hazard must be considered
in any building with an electrical supply.

cable_image.png

Mark Hodges
Mon, 08/30/2021 - 11:50
​Figure 3: Cables dislodged from suspended ceiling fixings following a fire in compartment –
photograph courtesy of Brian M

Most cables are sheathed or protected with polyvinyl chloride (PVC), polyethylene (PE) or
thermoplastic polyurethane (TPU). In a fire, these plastics release dioxins, hydrogen cyanide and

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hydrogen chloride. See National Operational Guidance: Fires and firefighting – Smoke and fire
gases.

From 1 January 2016, regulations require that all new wiring systems use metal, rather than plastic,
to support cables in escape routes, to prevent their premature collapse in a fire. Electrical
installations fitted before changes to the regulations, or that do not conform to the regulations,
may still present a hazard.

Further reading

Harrow Court (Hertfordshire Fire and Rescue Service)

Shirley Towers (Hampshire Fire and Rescue Service)

Fire and Rescue Service Immediate Bulletin 4/2011

             Control measure - Situational awareness: Cables

Control measure knowledge

Where areas involving lightweight conduit, trunking and cable fixings are identified, effective
control measures should be implemented to limit the hazards to emergency service personnel and
occupants.

Presence of these fixings may be identified by inspecting other compartments in the building, or
similar nearby properties.

Thermal imaging cameras (TIC) may assist in identifying internal fixings that have been subjected to
heat, either from processes within the premises or after being exposed to fire, as they may not be
readily identifiable by the naked eye. If operations are taking place at night a thermal imaging
camera may prove invaluable.

Strategic actions

Fire and rescue services should:

      Consider providing specialist equipment, such as anti-entanglement covers/straps and cable
      cutters to minimise the risk of entanglement and optimise the likelihood of successful self-

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release

      Have arrangements for thermal imaging equipment to be made available at incidents

Tactical actions

Incident commanders should:

      Identify and communicate the presence of lightweight conduit, trunking and cable fixings

      Assess the likelihood that cables and fixings will fail increasing the risk of entanglement

      Consider the use of thermal imaging cameras to identify hazards and locate casualties

      Identify loose cables and consider using alternative access and egress routes or defensive
      tactics

            Control measure - Isolate utilities

Control measure knowledge

It may be necessary to isolate utilities for the safety of occupiers and emergency service personnel.
Refer to the National Operational Guidance: Utilities and fuel, hazard of Dealing with utility or fuel
supplies at an incident.

If there evidence or suspicion of illegal activity involving electricity refer to National Operational
Guidance: Utilities and fuel, hazard for Illegal activity involving electricity.

Strategic actions

Fire and rescue services should:

      Liaise with local utility supply companies and maintain up-to-date emergency contact details

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in their fire control rooms

      Ensure that Site-Specific Risk Information (SSRI) contains details of utility shut-off facilities in
      commercial premises

Tactical actions

Incident commanders should:

      Isolate any utilities that may affect the incident or crew safety, and secure against
      reconnection

      Consider the impact of isolating electricity to the business continuity of premises

            Control measure - Remove or secure internal
            fixings or cables

Control measure knowledge

To maintain access and egress from the scene of operations, crews should remove or secure
internal fixings or cables where possible, subject to confirmation by a competent person that
services have been isolated.

Strategic actions

Tactical actions

Incident commanders should:

      Consider a controlled release of cables from trunking prior to committing crews

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Secure loose cables or consider removing them if the electrical supply has been isolated

            Control measure - Firefighter emergency
            arrangements: Cables

Control measure knowledge

Entrapment of crews in cables may occur due to unseen fire spread or unidentified cables
becoming affected by fire. Procedures for extrication should be in place prior to committing crews
to an environment where cables may be present.

Movement by entrapped personnel may become difficult; where possible the person should
remain still and be cut free from cable entrapment. Live cables may damage cutting equipment,
consider isolating electrical supplies. If this is not possible, personnel should consider attempting
self-release techniques such as finding an area close to a wall, where cables are still attached, and
moving slowly whilst attempting to release cables.

Strategic actions

Fire and rescue services should:

      Consider providing rated insulated cutters for cutting electrical cables

      Provide information and instruction to crews on the risk of cable entanglement and release
      techniques

      Provide breathing apparatus equipment that minimises the risk of cables becoming
      entangled, especially between cylinder and back plate

Tactical actions

Incident commanders should:

      Brief crews on any identified risk from the presence of cables prior to entering risk area

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Ensure that cable cutting equipment is available at incidents involving the risk of
      entanglement

      Establish emergency arrangements appropriate to the size and complexity of the incident

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