Insurance for contract engineers: what sites ask to see

It's 6.40am at the gatehouse. You've driven an hour for a breakdown on a case packer. The security guard rings through, and the site's health and safety lead comes down with a clipboard.

"Can I see your public liability certificate?"

You find it in your email. It ran out in July. The renewal is sat unopened in your junk folder.

Nobody gets hurt. You still lose the morning, and the site rings someone else next time.

Insurance is one of the first things a site checks, because it's one of the easiest. Most engineers carry the right cover. Where they get caught is the paperwork: wrong name, wrong dates, wrong description of the work.

Why the site asks

When a site brings in a contractor, the law expects it to check that contractor can do the job safely. HSE's guide for businesses that use contractors puts it bluntly: "Don't assume someone is competent, check it yourself" (INDG368).

The same guide gives a list of questions to ask a contractor. One of them is "If required, do you have Employers' Liability Compulsory Insurance?" Most sites turn that list into an approval form, and add public liability because their own insurer wants it.

So the person with the clipboard is doing their job, and you'd want the same check on every other contractor there. Contractors on site covers what the site owes you in return.

Public liability: the one everyone asks for

Public liability covers you for claims made against you by members of the public or other businesses. It doesn't cover claims from your own employees. HSE notes that public liability insurance "is generally voluntary" (HSE40).

Voluntary in law. In practice, very few sites will let you through the gate without it. Each site sets its own minimum limit, usually in its contractor terms. Check that number before you buy or renew. A broker may suggest one figure while the sites you want to work for ask for more.

Public liability insurance explained goes into what it does and doesn't pay for.

Employers' liability: only if you employ someone

This is the one the law makes compulsory, but only once you become an employer. You must then be covered for at least £5 million* from an authorised insurer. You can be fined £2,500* for every day you're not properly insured. You must display the certificate where employees can see it, and show it to inspectors when asked (GOV.UK).

A sole trader working alone doesn't employ anyone, so there's nothing to cover. If you trade through your own limited company, HSE lists an exemption for companies employing only their owner, where that person owns 50%* or more of the shares (HSE40).

The trap is the second pair of hands. You take a mate along to help on a shutdown and pay them cash. Calling them self-employed doesn't settle it. HSE is clear that what counts is "the real nature of your relationship" and how much control you have over their work (HSE40). Talk to your insurer before anyone works for you, not after.

If a site form asks for employers' liability and you work alone, say so in writing. The question in INDG368 starts with "If required" for a reason.

Professional indemnity: sometimes

Public liability is about injury and damage. Professional indemnity is about bad advice or bad design costing the client money.

Most breakdown work doesn't need it. Some work does. Changing a PLC program, signing off a machine modification, commissioning a new line or writing a specification all put your judgement on the line. If a site asks for professional indemnity, ask what work they think it covers. Then ask your broker whether your policy covers it too.

What the certificate needs to show

Before you send a certificate, read it like a site would:

• the name on it matches the name on your invoices
• the dates cover the job, start to finish
• the limit meets or beats the site's minimum
• the business description matches the work you actually do

That last one matters more than people think. A policy written for "mechanical fitter" may not cover you for electrical work, hot work or work at height. Ask your insurer in writing, and keep the reply. If you do hot work, read hot work permits for maintenance as well.

Check your insurer is authorised, too. GOV.UK points you to the Financial Conduct Authority register for employers' liability insurers (GOV.UK), and the same check works for any policy. The premiums count as a business cost: insurance is listed among the allowable expenses if you're self-employed (GOV.UK).

Our view

Buy cover for the work you really do, in the name you trade under, at the limit your best sites ask for. Then make it easy for them.

Keep one PDF with everything a site asks for at the gate: insurance certificates, tickets, right to work documents and a short list of the kit you bring. Send it the moment the job's confirmed. Engineers who send that pack without being asked get remembered.

What to do on Monday

1. Find your current certificate. Check the expiry date, the name and the limit.
2. Read the business description on your policy schedule. If it doesn't match your work, ring your insurer.
3. Ask the sites you want to work for what minimum limit they need.
4. Put your site pack together as one PDF, and set a renewal reminder a month before expiry.

* The £5 million employers' liability minimum, the £2,500 daily fine and the 50% shareholding exemption correct as of 12 September 2026. Check GOV.UK's employers' liability guide and HSE40 for the latest.