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Control measure
Safe system of work: Low-voltage electricity

Control measure knowledge

Low-voltage electricity should be isolated and earthed, or otherwise made safe where it is appropriate to do so. 

It may not be possible for personnel to isolate and make safe the electricity supply using normal methods. In this situation assistance will be required from the relevant electricity supplier or competent person to make the electricity supply safe. Until the supply is made safe personnel should operate at a safe distance.  

In some circumstances, leaving specific power systems on could be beneficial in resolving the incident. 

Electrical isolation to small premises can be achieved by isolating electricity at the consumer unit (or fuse board) or by removing the supplier’s main fuse, found on the supply side of the meter. 

Removal of this fuse could be carried out by personnel in urgent circumstances. Due to the possibility of small quantities of asbestos being present in older fuses, appropriate personal protective equipment (PPE) and respiratory protective equipment (RPE) should be worn. 

All commercial premises will have electricity isolation points at the electrical intake. At larger sites, there may be isolation points that control areas of the site or separate pieces of machinery and equipment. Isolating any electrical supplies should be considered as soon as possible, taking into account any wider impact on other essential systems, installations or work processes. 

If personnel need to deal with three-phase power supplies, they may need to request assistance from the electricity supplier, unless there are on-site engineers competent in dealing with, and controlling, this hazard. 

If the electricity supply has been isolated, a robust system should be implemented to ensure it is not reconnected. This may involve the use of locks, signs or supervision. 

Performing rescue of a casualty 

If it can be determined that a casualty is in direct contact with low-voltage electricity: 

  • Carry out a risk assessment 
  • Pull the casualty clear, using electrical gloves or other dry insulating material 

Strategic actions

Fire and rescue services should:
  • Ensure fire control room records include emergency 24-hour contact details for support in isolating electricity

Tactical actions

Incident commanders should:
  • Identify on-site electrical installations and their isolation points

  • Identify, implement and manage safe distances for electrical supplies that cannot be isolated

  • Isolate the electrical supply if appropriate

  • Implement appropriate procedures to prevent the electrical supply being switched on inadvertently

  • Seek specialist advice where the electrical supply cannot be isolated

  • Perform rescues using electrical gloves or dry insulating material