To choose an NEC form of contract, start from what you are buying, not from the form you used last time. Five questions will settle it in most cases: what is being bought, one job or many, how risky it is, where you sit in the chain, and how you want to pay.
This guide uses the NEC4 names. For a description of each form, see the overview of NEC contract types.
The five questions
- What are you buying? Physical work points to the ECC family, advice or design to the PSC family, an ongoing service to the TSC or FMC family, and goods to the SC family.
- Is it one defined job or a service over time? A single end date suits the ECC. Repeated, partly unknown work over a period suits a term contract with Task Orders.
- Is it straightforward and low risk? If so, consider a short form. The test is the nature of the work and how much management it needs. No NEC contract sets a price limit.
- Are you the employer of the work, or letting part of your own contract? If you hold a main contract and are passing work down, you need the subcontract form.
- How should the risk of cost be shared? This picks the main Option where the form offers one. See choosing a main Option.
The decision table
| Your situation | Usual starting point |
|---|---|
| A new building, road or plant, with design by anyone | ECC |
| Repairs to a small car park, with a clear scope and no real unknowns | ECSC |
| Letting groundworks under your NEC4 main contract | ECS, or ECSS if the package is simple |
| Appointing a lead designer on a complex scheme | PSC |
| A one-off survey or short advisory task | PSSC |
| Passing part of a consultancy appointment to another firm | PSS |
| Five years of highway drainage maintenance | TSC |
| Grounds care at one site, with simple pricing | TSSC |
| Cleaning, security and building services across an estate | FMC |
| Buying a large transformer with installation support | SC |
| Regular deliveries of a standard product | SSC, using Batch Orders |
| One contractor to build an asset and then run it for years | DBO |
| Client, designers and contractors sharing risk across a programme | ALC |
| Several suppliers on call for packages not yet defined | FC with orders under other forms |
These are starting points, not rules. Treat each as a prompt to read the form and check that it fits.
Worked examples
A fictional school extension
A council needs a two-classroom extension on an occupied site, with phased access and a live kitchen next door. The value isn't large, so someone suggests the ECSC. But the phasing and the interfaces with the school need a programme everyone can rely on, and the client wants Key Dates for each holiday. The short form has no Key Dates, so the ECC with a simple Option is the better choice, even at this size.
A fictional water authority
A water authority wants pipe repairs across a region for three years. It doesn't know where the bursts will be. An ECC per repair would mean constant procurement. The TSC fits: a Price List set at tender, then a Task Order for each piece of work. The ECC vs TSC comparison sets out the differences. If a large planned mains replacement appears within that programme, the authority should consider whether that piece deserves its own ECC.
When the answer is not clear
- Work and service are mixed. Decide which is the main purpose. A contractor building an asset and then maintaining it might be on the DBO. Two separate contracts may also be better if the phases have different suppliers.
- Design plus construction. The ECC covers Contractor design by itself. You don't need a professional service form for that, although the design firm's own appointment under the Contractor might be a PSS.
- Supply plus fitting on site. If substantial site work is involved, the ECC with Plant and Materials could be a better fit than the SC. Take advice on whether the Construction Act then applies.
- Short form appeal. A short form saves effort only if the job stays simple. The ECC vs ECSC comparison has a checklist.
Check before you commit
- Is the edition the same across your main contract and subcontracts, or are you knowingly mixing them?
- Does your team know who will act as Project Manager, Service Manager or Supply Manager? Under a short form, is the Client ready to do that itself?
- Have you decided who completes each part of the data sheets, and what must go in the Scope?
- Which secondary Options do you need, and does the form offer them? Short forms have none. The guide to secondary Options helps.
- Have you asked a contracts adviser about anything unusual? A form choice is hard to undo once tenders are in.
Related guides
- NEC Contract Types: Which Form Do You Need?
- NEC4 Engineering and Construction Contract (ECC)
- NEC4 Engineering and Construction Subcontract (ECS)
- NEC4 Engineering and Construction Short Contract (ECSC)
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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.