Confined Space Electrical Work UK: Safety Requirements

• Regulation 4 — Work in confined spaces (avoid entry) — entry must be avoided wherever it is reasonably practicable to do the work without it. This means considering whether the work can be done from outside the space using remote tools, cameras, or modified working methods before permitting entry.
• Regulation 4 — Safe system of work — where entry cannot be avoided, Regulation 4 also requires that a safe system of work be established before any person enters. This must address all the identified specified risks through risk assessment.
• Regulation 5 — Emergency (rescue) arrangements — adequate rescue arrangements must be in place before entry. These must not rely on emergency services for immediate rescue — the response time for emergency services is often too long to prevent a fatality from oxygen deficiency.

• Entrant — the person working inside the confined space. Must be medically fit for confined space work, trained in confined space procedures, wearing appropriate PPE, and carrying a personal gas alarm. Must maintain regular communication with the standby person.
• Standby person — stationed outside the space for the entire duration of the entry. Responsible for maintaining communication, monitoring the atmosphere at the entry point, operating the rescue equipment (tripod, winch, lifeline), and initiating the rescue plan if the entrant fails to respond or the alarm sounds. The standby person must NOT enter the space alone.
• Rescue team — for high-risk confined spaces, a trained rescue team (minimum two persons in addition to the standby) must be on standby and ready to effect a rescue. Rescue must where possible be carried out without entry — using a winch, lifeline, and rescue harness worn by the entrant. Entry-based rescue is only a last resort and requires full self-contained breathing apparatus (SCBA).
• Do not enter to rescue without SCBA — if the entrant becomes incapacitated due to an atmospheric hazard, entering without breathing apparatus will incapacitate the rescuer. Multiple fatalities in the UK have occurred because well-intentioned rescuers entered a toxic atmosphere without protection. Initiate non-entry rescue (winch and lifeline) and call 999 immediately.

• Reduced voltage requirements — use 110V CTE (centre-tapped earth) supply from a transformer for all portable power tools. In wet or damp confined spaces, consider 25V or battery-powered equipment. The HSE strongly recommends 110V as the maximum for portable tools in confined spaces.
• RCD protection — where 230V is unavoidable, a 30mA RCD must be used. In wet conditions, a 10mA RCD should be considered. RCDs must be tested before entry using the integral test button.
• Increased shock risk from earth contact — in a confined space, the body may be in contact with a conductive surface (metal tank, damp concrete, damp earth) which provides a low-resistance path to earth. Contact with any live conductor in this situation is more likely to be fatal than in an open environment.
• Safe isolation before entry — all electrical services in or adjacent to the confined space must be identified and considered for isolation before entry. Apply lockout tagout (LOTO) procedures to prevent inadvertent re-energisation during the period of entry.

• All equipment must be ATEX rated — this includes torches, multi-gas detectors, radios, mobile phones, and test instruments. If you carry an item into an ATEX zone that is not rated for that zone, you are introducing a potential ignition source.
• Intrinsically safe (Ex i) equipment — intrinsically safe equipment is designed so that the electrical energy within the equipment is too low to cause ignition. It is the most common ATEX protection concept for test instruments and portable devices used by electricians in Zone 1 and Zone 2 areas.

Statutory References for Electricians — Potentially Explosive Atmospheres

BS 7671 requires that for installations in potentially explosive atmospheres, reference be made to all four of the following instruments:

• Electricity at Work Regulations 1989 (EAWR) — the overarching duty to prevent danger from electrical systems.
• Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) — requires employers to assess and control risks from flammable substances, classify zones, and select appropriate equipment.
• Petroleum (Consolidation) Regulations 2014 — applies where petroleum spirit is stored or handled; relevant to forecourts and fuel storage installations.
• Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016 (ATEX 2016) — governs the selection and use of ATEX-rated equipment in classified zones.

• Confined space permit contents — space identification, hazard assessment and specified risks, atmospheric test results (pre-entry), isolation details (electrical, mechanical, process), PPE requirements, entry personnel names, standby and rescue arrangements, communication method, duration of validity, and authorising signature.
• Integration with electrical isolation permit — where a permit to work is also issued for electrical isolation (see the LOTO guide), the two permits must be cross-referenced. The confined space permit should reference the isolation certificate number and confirm that isolation is confirmed.
• Permit suspension and cancellation — if atmospheric conditions change, work must stop and all personnel must exit. The permit is suspended and a new atmospheric test must be carried out before re-entry. When work is complete, the permit is formally cancelled by the authorising person after confirming all personnel have exited and equipment has been removed.

Pre-Entry Equipment Checklist

The following items are required before any person enters a confined space for electrical work, in accordance with Confined Spaces Regulations 1997 safe systems:

• Gas detector / atmospheric monitor — calibrated, multi-gas (O₂, %LEL, H₂S, CO as a minimum). Tested with a calibration gas before entry.
• Intrinsically safe (Ex i) torch and lighting — specifically ATEX-rated intrinsically safe luminaires, not just any battery torch, where the atmosphere may be flammable.
• Rescue kit — rescue harness worn by the entrant, lifeline attached to a tripod or anchorage point, fall-arrest and retrieval lanyard.
• Tripod and winch — required for all vertical entry confined spaces (manholes, chambers). The standby person must be trained to operate the winch for non-entry rescue.
• Communication radio — two-way communication between the entrant and the standby person. Where ATEX zones apply, the radio must be ATEX-rated for the zone.
• Harness and lanyard — a full-body rescue harness (not just a waist belt) worn by the entrant for the duration of entry to enable mechanical retrieval.