JCT Terms in NEC Language

JCT and NEC often describe similar ideas in different words, so this table gives the closest NEC term for each familiar JCT phrase. Treat it as a way in, not an exact translation: several NEC terms work differently from the JCT term beside them, and those differences are where people get caught.

NEC terms here are from the NEC4 ECC, with NEC3 names noted. JCT terms differ across forms and editions. For the bigger picture, read JCT vs NEC: the main differences or return to the NEC comparisons overview.

People and documents

JCT term	Closest NEC4 ECC term	How it differs
Employer	Client (NEC3: Employer)	Same party, new name in NEC4
Architect / Contract Administrator	Project Manager	The Project Manager acts for the Client and isn't framed as an independent certifier in the JCT way
Employer's Agent	Project Manager	A loose match; the NEC role has its own duties and time limits
Clerk of Works	Supervisor	The Supervisor has defined contractual powers over tests and Defects
Contract Particulars	Contract Data	In two parts, one from the Client and one from the Contractor
Employer's Requirements; specification and drawings	Scope (NEC3: Works Information)	A single defined term for what is to be provided and any constraints on how
Contractor's Proposals	Part of the Scope; Contractor's design goes through acceptance (21)	No separate standard label
Contract Bills	Bill of Quantities (Options B and D only)	Options A and C use an Activity Schedule instead
Contract Sum	Total of the Prices	What "Prices" means depends on the main Option
Base Date	No direct equal; the Contract Date is the nearest reference point	Not the same test, so check what your contract uses it for

Time

JCT term	Closest NEC4 ECC term	How it differs
Date for Completion	Completion Date	Moves mainly through implemented compensation events or agreed acceleration
Practical Completion	Completion	NEC defines it, relying heavily on what the Scope requires by the date; don't read JCT practice across
Master programme	Accepted Programme	Far more content is required, and it sets the baseline for assessing delay
Relevant Event / extension of time	Compensation event changing the Completion Date	Assessed from its effect on planned Completion, so the delay may not equal the days lost on one activity (63.5)
Sections and Sectional Completion	Option X5	Secondary Option, included only if chosen
Partial possession	Take over (35), and possibly 60.1(15)	Taking over part early can be a compensation event
Liquidated damages	Delay damages, Option X7	Apply only if X7 is chosen
Non-Completion Certificate	No equivalent	X7 doesn't rely on this kind of certificate

Money and change

JCT term	Closest NEC4 ECC term	How it differs
Variation	Change to the Scope, 60.1(1)	Assessed as a compensation event on Defined Cost plus Fee, not by default on contract rates
Loss and expense / Relevant Matter	Compensation event	Handled in one assessment with the time effect
Interim Certificate / valuation	Payment certificate (51.1), following an assessment (50.1)	The Project Manager assesses it, and it is based on the Price for Work Done to Date
Final Certificate / final account	Final assessment (53)	New in NEC4 and tied to the Defects Certificate or a termination
Pay Less Notice	Pay less notice, Option Y(UK)2	Construction Act concept in both
Fluctuations	Option X1	Index-based, and available only with the main Options that allow it
Retention	Option X16	Applies only if chosen
Provisional sum	No standard equivalent	Often handled through the Scope, a later compensation event or an amendment
Dayworks	No direct equivalent	Assessment uses Defined Cost; the Schedule of Cost Components sets out what counts

Quality, security and disputes

JCT term	Closest NEC4 ECC term	How it differs
Rectification Period	Defects date and defect correction periods	Two separate ideas: when the hunt for Defects ends, and how long each correction may take (44.2)
Certificate of Making Good	Defects Certificate	Issued at the defects date, or later if notified Defects remain, and can list outstanding Defects
Performance bond	Option X13	Secondary Option
Parent company guarantee	Option X4	NEC4 refers to the ultimate holding company
Collateral warranties / third party rights	X8 undertakings, Y(UK)3	Check exactly what has been selected
Contractor's Designed Portion	Contractor's design set by the Scope; X15 covers liability	No separate standard "portion" concept
Adjudication and arbitration or litigation	Dispute resolution Option W2 under the Construction Act; W1 where it doesn't apply	Only one W option is chosen, and the final tribunal is named in the Contract Data
Determination	Termination (90 to 93)	Uses a table of reasons, procedures and payment

Four words that catch out JCT users

• "Accept". Accepting a programme or design doesn't take away the Contractor's responsibility. The Project Manager's response has its own rules and permitted reasons for refusal.
• "Others". This is a defined term for people outside the contract, not a general word.
• "Defect". It is measured against the Scope and the applicable law, not against a general idea of poor work.
• "Notify". Many NEC communications must be separate notifications. A mention in the minutes may not be enough, and clause 13 is worth reading early.

Related guides

• NEC vs Other Construction Contracts
• NEC vs FIDIC
• NEC vs ICC
• NEC vs GC/Works
• JCT vs NEC: The Main Differences
• Difference Between JCT and NEC for Clients

This guide is general information in our own words, not legal advice. Your contract and its Contract Data always govern. NEC, NEC3 and NEC4 are trade marks of Thomas Telford Ltd; Contract Status is not affiliated with or endorsed by NEC.