SiteIt's the second week of December. The Christmas shut starts on the 27th. The scope's signed off, the bearings and belts are on the shelf, and the crane hire is booked.
Then you ring round for four extra fitters and a controls engineer. The first agency has two fitters, neither of whom has seen a palletiser. The second has nobody until January. A contract sparky you used last year says sorry, they're booked by the site up the road.
You go into the shut two people short. The gearbox change slips to day four. The conveyor retrofit gets cut. You restart on the 3rd with half the list done and a promise to "pick it up at Easter".
Most shutdowns that overrun don't run out of parts. They run out of people. And people are almost always booked last.
Everyone shuts at once
The reason is simple. Christmas, Easter and the August fortnight are when most factories and warehouses stop. Every maintenance manager in your area wants extra hands in the same ten days. The good engineers know it, and they fill their diaries early.
So treat people like long-lead parts. If a gearbox has a ten-week lead time, you order it in week ten. A named controls engineer for a Christmas shut is the same. If you're following a 12-week countdown for the shutdown, people belong in weeks 10 to 8, next to the parts.
Here's our view. Confirm names, not headcount, at least six weeks out. "Four fitters" on a booking means you'll get whoever's free. "Four fitters, two with Siemens drives, one with a hot work ticket" means someone has to find the right ones.
Book the job list, not a number
Agencies have to get enough information from you to pick a suitable engineer. The Conduct Regulations list what that includes: the dates, the type of work, the hours, the location, and "any risks to health or safety known to the hirer" with the steps you've taken to control them (regulation 18). They also cover the experience, training and qualifications you think the job needs. We cover the rest of that law in what the Conduct Regulations mean when you take an agency engineer.
For a shut, the easiest way to give them that is the job list itself. Cut it down to the tasks you need outside help with:
- change the main drive gearbox on line 2, with a crane lift on day one
- replace and tension the infeed belts on the case packer
- swap the safety relays on the robot cell and prove the interlocks
- strip and rebuild two hydraulic power packs
Then say which trade each task needs and who on your team leads it. An engineer who's seen the list before they arrive turns up with the right tools and the right questions.
Watch the hours
Shutdowns run on long shifts. Twelve hours for ten days straight is common. That's where tired people make mistakes, often on the day the guards come off and the stored energy is still in the machine.
The Working Time Regulations still apply. Workers can't work more than 48 hours a week on average, "normally averaged over 17 weeks*", unless they've opted out (GOV.UK, maximum weekly working hours). They have the right to 11 hours* rest between working days (GOV.UK, rest breaks). Some shift workers can't get their normal rest between shifts. Those workers may be entitled to "compensatory rest" instead (GOV.UK, compensatory rest).
A short shut averaged over 17 weeks won't break the 48-hour average on its own. Fatigue is a different matter. HSE is clear that "the legal duty is on employers to manage risks from fatigue", whatever an individual is willing to do (HSE, fatigue). An agency engineer who comes off a shut at another site the day before yours is a risk you should know about. Ask.
We'd rather book one more engineer than stretch the crew to fourteen-hour days. We set out the wider case in overtime as cover: when it works and when it breaks people.
Get the paperwork done before day one
Day one of a shut is the worst time to find out someone's ticket has lapsed. Ask for it all a week before:
- written confirmation from the agency that identity and right to work are checked (right to work checks for agency and contract engineers)
- copies of any tickets the tasks need, such as hot work, slinger signaller or MEWP
- a start time for induction that isn't the same hour the crane arrives
You also owe them information. If engineers from another employer are working in your site, their employer must get "comprehensible information" on the risks and the measures you've taken (Management Regulations 1999, regulation 12). HSE's guide to using contractors (INDG368) puts the rule for supervision in one line: "the greater the risk, the more you need to do."
Shutdown work is full of permits. Hot work, confined spaces and line breaks all need one. Make sure every outside engineer knows how your permit to work system runs before they need a permit signed.
Keep someone for the restart
The last day of a shut is when the crew thins out. The agency engineers finish at six. The line starts at ten the next morning. The first fault shows up at half past.
Book at least one of your outside engineers for the first shift back. Pick someone who worked on the riskiest job. They know what was touched, and they'll find the loose terminal faster than anyone.
The cost of being two short
Work out what a day of overrun costs before you decide you can manage with fewer people. Lost output, overtime to catch up, missed deliveries. The method is in what an hour of downtime really costs you. Multiply by the hours in a day. Then compare it with the cost of two more engineers for the shut. Put your own figures in. We think the extra engineers come out cheaper far more often than not.
What to do on Monday
- Put your next shutdown dates in the diary and count back ten weeks. That's when you start booking people.
- Turn the job list into a booking sheet: task, trade, tickets, hours.
- Ask each agency or contractor to confirm names, not numbers, six weeks out.
- Book one outside engineer for the first shift after the restart.
* The 48-hour average, 17-week reference period and 11-hour daily rest figures are correct as of 22 October 2026. Check GOV.UK's working hours guidance and rest breaks guidance for the latest.