Reference library
The source belongs
beside the answer.
A cable calculation, an earthing check or a DNO submission starts with the right reference. OpsWork brings the engineering question, source material and project context into the same working record, ready for an engineer to check.
Technical queries and referencesReference register
Recognisable references. Clear access conditions.
These examples show the references used in the work. Use the current edition and hold any licence required by its publisher.
| Reference and title | Referenced edition | Access |
|---|---|---|
| ENA EREC G99 Requirements for the connection of generation equipment in parallel with public distribution networks on or after 27 April 2019 | Issue 2, March 2025 | Publisher access conditions apply. Copyright is retained by ENA. |
| BS EN 50522 Earthing of power installations exceeding 1 kV a.c. | 2022+A1:2024 | Licensed BSI content. The customer must hold appropriate access rights. |
| CDM 2015 The Construction (Design and Management) Regulations 2015 | SI 2015/51 | Public legislation; consult the publisher for amendments and licence conditions. |
| NEC4 Engineering and Construction Contract | June 2017, revised January 2023 | Licensed contract text; review the actual contract and amendments agreed for the project. |
Technical clarity
Two distinctions that matter.
- G99: 16 A per phase
- G99 connection procedures apply to generation and energy storage rated above 16 A per phase, or installations that do not meet G98. An 11 kV threshold does not define G99 applicability. Review the relevant DNO process and the applicable ENA document.
- L153: guidance on CDM 2015
- HSE's 2015 publication Managing health and safety in construction: Construction (Design and Management) Regulations 2015. Guidance on Regulations is guidance, not an Approved Code of Practice. The publisher provides a free copy under the stated access conditions.
Reference families
The material your engineers work with.
From network connection requirements to project contracts, this is the range of material behind engineering consultancy work. Agree the references and licensed access needed for your projects.
ENA recommendations and specifications
G98, G99, P28, P29 and G5; technical specifications 09-12, 09-17, 41-26, 41-36, 35-1, 43-8 and 43-122; Engineering Report S34. Legacy G83 and G59 references are retained for historic project context, not as a substitute for current connection requirements.
HSE guidance and electrical safety legislation
CDM 2015 and L153; HSG47, HSG85, HSG150, GS6 and GS38; the Electricity Safety, Quality and Continuity Regulations 2002. L153 is Guidance on Regulations, not an ACOP.
BSI and IEC engineering references
BS 7671; BS EN 50522, 60076, 62271-200, 62305, 61140, 60099-4, 60898-1 and 61936-1. IEC families include 60287, 60228, 60502, 60076, 60909, 62271 and 61936. Legacy BS EN 60044-1 and IEC 60044 references are retained for historic context: check the applicable replacement and edition.
NEC4 contracts and options
Engineering and Construction Contract (ECC), Engineering and Construction Subcontract (ECS), Professional Service Contract (PSC) and Term Service Contract (TSC). Main options, secondary options and Y(UK) clauses depend on the selected contract and its amendments; not every option belongs to every form.