Executive summary
Date(s) of inspection:
January 2025
Aim of inspection
This is a target inspection to assess governance arrangements and gain assurance that temporary electrical installations are being appropriated installed and manged to comply with the Electrical at Work Regulations 1989, BS 7671 & BS 7375.
Subject(s) of inspection
- CDM 15 - Rating: GREEN
- Health & Safety at Work Act - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The inspection focused on the control of electrical isolations and the safe systems of work on the non-permanent electrical installation in the construction site area only. Three contractors (BYLOR, MEH & Dalkia) along with NNB GenCo’s role as the principal contractor were inspected.
The Electrical Safe Systems of Work were all compliant with the Electricity at Work Regulations 1989 but were at differing stages of implementation maturity on site, with BYLOR the most mature to Dalkia the least. A number of issues were raised within the inspection with the most significant a non-compliance with BS 7671 on a non-permanent installation of an electrical socket (equipotential earth bonding missing), this was a contributing factor in a previous electrical shock event. These failings do question the validity of the Electrical Installation Certificates and Periodic Testing which should identify these non-conformance, this will be followed up during future inspections. BYLOR and MEH both have audit programs in this area and the documentation sampled was compliant, again I will follow this up during future regulatory engagements. Another non-compliance identified was within the MEH permit office where the electrical system mimic did not reflect the state of plant, with another non-compliance on permit (lock out) key location. The immediate remedial actions (delivered overnight) on both the mimic and non-compliant socket, I considered adequate for compliance to the relevant standards (BS7671 &HSG253) through review of appropriate documentation.
NNB GenCo presented their review of the electrical safety events across HPC from the past 4 months; There were 2 High potential events (HPE) reported where the IP had come into contact with live conductors, the second was still under NNB GenCo investigation. But there were 70 potential electrical shock events identified by this review. This latter figure is grossly out-with similar OPEX from all duty holders across GB Nuclear sites and does not align with what was witnessed during the inspection sampling. This suggests a misalignment of event reporting/sanctioning compared to identified relevant good practice. NNB GenCo has since reviewed reporting criteria and shared the output with the Lead Site Inspector (ONR), the criteria for potential shock events was too sensitive offsetting this figure. Even though NNB GenCo were reviewing data weekly for electrical safety events, from insight, and chairing bi-weekly meetings with cross-site contractors to discuss but had not trended this data over a greater period previously and potentially missing growing trends/areas of risk There is a L4 RI for NNB GenCo to review their Electrical Safety Event criteria, trending and reporting across site to relevant parties.
There was no common standard for Lock out Tag out with the main deviation between the contractors the colour of the relevant padlocks, although all isolations sampled across each contractor were compliant with Health and Safety Executive’s (HSE) The Safe Isolation of Plant and Equipment (HSG253). I raised, for consideration, a standardised approach across the whole site to reduce the risk of human error. Dalkia will be the sole organisation responsible for the non-permanent electrical installation in the near future, but they are the least mature on site in terms of Appointed Personnel (AP Electrical) and at this point did not have a dedicated permit office unlike BYLOR, who have 11 offices. I raised my concerns on their current organisation capability and the resources they would require to safely manage all non-permanent electrical installations, with will also be followed up during future inspections.
Conclusion
On the basis of the evidence sampled, I judge that NNB GenCo, BYLOR, MEH and Dalkia have adequate arrangements under the Health and Safety at Work Act 1974, and The Electricity at Work Regulations 1989 for control of non-permanent supplies on the construction site. Upon consideration of the ONR guidance (GD-064) in relation to inspection ratings where relevant good practice was generally met with any shortfalls identified rectified back to compliance with the relevant standards and industry good practice.
Therefore, I judge that a rating of Green (no formal action) with L4 RI Electrical Safety Event Review and dissemination appropriate.