SiteIt's 3am. The filler's down with a worn bearing on the main drive. Your fitter says two hours to change it properly. The shift manager has three trailers booked from six and a customer who fines late loads.
"Can't you just run it till the end of the shift?"
"No."
"What about taking the guard off so you can get at it while it turns?"
That's when it starts. Voices go up. Someone rings you. By the time you've woken up enough to answer, the fitter is angry, the shift manager is angry, and the bearing still isn't changed.
The row itself costs you time. Worse, it pushes good people into bad calls. The fix is to agree who decides what before 3am ever comes round.
They're both right
Nobody in that row is the villain. The shift manager is paid to ship product. They've got trailers, a customer and a plan that's falling apart. The fitter is paid to keep the kit safe and running, and they're the one with their hands in the machine.
From where each of them stands, they're right. Production sees a stood line costing money every minute. Maintenance sees a job that will fail again in an hour if it's rushed. Both are true.
What goes wrong is that nobody has said, in advance, whose call is whose. So it gets settled by whoever shouts loudest, or whoever is senior on shift. Neither is a good way to decide whether a guard comes off.
Pressure does the damage
HSE's guidance on human failure is useful here. It describes violations, meaning shortcuts and work-arounds, as "usually well-meaning". They "usually result from an intention to get the job done as efficiently as possible" (HSE, human failure). The same page lists time pressure as one of the things that make errors more likely.
That's the 3am row in two lines. Nobody wants to get hurt. They want the line back.
Nights make it worse. HSE notes that accidents and injuries have been found to be higher on night shifts. Fatigue also brings "underestimation of risk" (HSE, fatigue). So the shift where tempers run shortest is also the one where judgement is weakest. HSE's maintenance page flags the same tension. Confusion and accidents are more likely when maintenance happens "during normal production work" (HSE, maintenance).
Split the decisions in daylight
Here's our view. Production owns the priorities. Maintenance owns the method. Nobody outranks an isolation.
Write it down and put both names on it:
- Production decides which line gets fixed first, what to tell the customer, and how to use the operators while the line is down.
- Maintenance decides how the job is done, how long it really needs, and when it's safe to run.
- Nobody asks for a guard off, an interlock bridged or a live repair to save time. If one is truly needed, it goes through a permit and a manager, not a corridor chat.
- Either side can call you. Nobody calls you to win an argument.
The law already backs this up. Every employer has to make arrangements for the "effective planning, organisation, control, monitoring and review" of safety measures, and write them down once there are five or more staff (Management Regulations, regulation 5). A breakdown is exactly when those arrangements get tested. Employees have duties too. They must take reasonable care of themselves and others (HSWA, section 7). And they must tell the employer about a situation they would reasonably see as a "serious and immediate danger" (Management Regulations, regulation 14). So a fitter who refuses to run a machine with the guard off is doing what the law asks of them.
Give the shift manager a job
Half the row comes from the shift manager having nothing to do but wait and ask how long. So give them a job.
The fitter gives an update every 30 minutes. What they've found, what they're trying next, and a best guess at the time, with how sure they are. "Bearing's out, new one going in, 45 minutes if the housing's not damaged."
The shift manager runs plan B. Move operators to another line. Rebook the trailers. Ring the customer early, before half five. All of that is real work, and it takes the pressure off the person with the spanners.
Agree a trigger, too. If the fault isn't diagnosed in 30 minutes, the shift calls for help. Our post on the 30-minute rule covers how to set it.
Sometimes the row is about something else
Listen to a 3am row closely and you'll often hear a different problem underneath. The fitter is a good mechanical hand facing a drive fault or a PLC they don't know. They won't say so with the shift manager stood there. So they dig in, or they try things, and the clock runs.
HSE expects maintenance to be done by people "competent to do the work" (L22, paragraph 79). A mechanical fitter isn't automatically competent on a servo drive, and nobody should have to bluff it. Make it normal to say "this one needs an electrician" or "this needs a controls engineer". Then make sure someone can actually come. If you're not sure which trade you're short of, read fitters, electricians and controls engineers: who you really need.
The cost of not having that person is easy to see. Every hour the fitter spends out of their depth is an hour of a stood line. Put your cost per hour of downtime next to the cost of a callout and the choice is rarely close.
The morning after
Don't let the row become the story. The next day, sit both of them down with a brew. Ask what happened to the machine, then what happened between the people. Keep it about the system, not who was rude. Our post on five whys without a blame session has a simple way to run it.
And check how the line was handed back. If the restart was rushed, that's where the next breakdown starts. Who signs off the restart sets out a clean handover.
What to do on Monday
- Write one page that splits the decisions: production owns priorities, maintenance owns method. Get both managers to sign it.
- Brief every shift manager on the 30-minute update and the 30-minute trigger.
- Ask your fitters which faults they'd rather not face alone at 3am. Make a list.
- Line up who you'll call for each fault on that list, before you need them.
* Paragraph numbers refer to L22, fourth edition (2014, amended 2018).