Source: https://www.quantsurv.com/resources/glossary/z-clauses Content format: Markdown version of the public page. Content reviewed: 2026-09-30 # Z clauses: definition and example Extra conditions added to an NEC contract under Option Z, often where risk moves to you. By [Jack Butler-Kettle]() ยท Updated 30 September 2026 Guidance for England and Wales. Check the contract, amendments and facts that apply to your job. ## What it means in practice Read this alongside [the NEC Dictionary of Terms](). Z clauses are additional conditions used with NEC contracts. They can amend risk allocation or standard procedures, so the printed core clauses may not give the complete answer. References, document priority and interactions with the selected main and secondary options need to be read together. Mark every altered obligation before setting up your contract routine. A [pre-signing contract review]() can help identify amendments that need negotiation or clarification. ## Worked example ### The facts An NEC subcontract includes a separate schedule changing notice arrangements. ### What happens 1. The subcontractor reads the additional condition alongside the provision it affects. 2. It updates its planned administration process to match the agreed requirement. ### What this shows A familiar NEC form does not justify following an unamended procedure when the actual agreement says something different. ## Sources 1. [NEC Dictionary of Terms](). NEC Contracts.