What is a "technical business unit" (TBU)? Explained with real examples
Before you work out how to run social elections, you need to know for whom and where. That is the job of the technical business unit, the TBU (unité technique d'exploitation / technische bedrijfseenheid). It is the concept that trips up the most employers, because it almost never lines up with what you would expect: not the company, not the VAT number, not the building.
The definition, in one sentence
The TBU is the unit for which you set up a Works Council (WC) or a Committee for Prevention and Protection at Work (CPPW). It is the scope of the vote. The threshold of 50 workers (for the CPPW) or 100 (for the WC) is counted per TBU, and the elected representatives sit for that TBU.
The law defines it through two tests: economic autonomy (its own management, an identifiable activity) and social autonomy (a community of workers with its own cohesion, its own language, its own location, its own social history). These two tests can pull in opposite directions, and that is where the confusion starts.
The point that changes everything: a legal entity is not automatically a TBU. One company can contain several TBUs. Several companies can form a single TBU. The real organisation of work decides, not the commercial register.
The favour principle: doubt works for the workers
A legal detail with practical bite. When the tests hesitate, the law leans toward the option that produces more representation. In practice: if the economic tests point to one large unit and the social tests point to several smaller ones, the split that creates the most representation wins. The social tests take priority. Keep this in mind for the four cases below.
Case 1 — The multi-site company
One company, one registration number, three logistics depots in Antwerp, Liège and Charleroi, plus an administrative head office in Brussels. 260 workers in total.
The temptation is to count 260 and run a single election. That is often wrong. Each depot has its own local management, its own informal work community, its own working language. The social tests push toward four separate TBUs, and therefore four votes, with thresholds counted separately.
The result: a depot of 42 people falls below 50 and gets no CPPW, while the head office of 90 gets one. The way you draw the lines decides who votes, and the classic mistake is to reason from the company's total headcount.
Case 2 — The group of several companies
Three sister companies share the same shareholder, the same building, the same HR department, the same canteen. Taken separately: 30, 25 and 40 workers. None reaches 50.
Here the movement runs the other way. The social tests (same premises, shared personnel management, a community of workers who see each other every day) can merge the three legal entities into one TBU of 95 people. The threshold of 50 is crossed, and a CPPW must be set up.
This is the case where the employer believes they are out of scope because "each company is small", then discovers they had to run elections. Case law regularly groups entities together when the social signals stack up: single HR management, staff moving between the entities, shared internal communication.
Case 3 — The franchise network
One brand, forty outlets, each run by an independent franchisee with its own commercial contract. The franchisor sets the brand, the prices, the store layout.
The reflex is to say: "each franchisee is an autonomous employer, so each counts its own workers." That is the correct starting point, but not the end of the analysis. The real question is the degree of dependence. If the franchisor controls the opening hours, the rosters, the pay policy and the day-to-day management of staff, a judge can treat the franchisee's social autonomy as fictional and attach the workers to a wider TBU.
In most classic franchises, each store stays a TBU of its own and falls below the thresholds. But a tightly integrated network, where head office genuinely runs the teams, can tip the other way. Every case turns on its facts.
Case 4 — Split legal entities
The trickiest case. A single activity is spread across two companies: one holds the employment contracts (an in-house HR services company), the other runs the activity and gives the daily instructions. On paper, the employing company has 120 "seconded" staff; the operating company has 8.
The economic and social tests both point to the operating company: that is where people work, take their orders, form a community. The fact that the contracts are signed elsewhere does not move the TBU. The 120 workers belong to the TBU where the work actually happens. Splitting the legal employer artificially to slip under a threshold does not work: the law looks at the reality, not the structure on paper.
What you have to do, in practice
The TBU is not a one-sided decision by the employer. The proposed split is discussed with the trade unions and communicated on day X-60, that is late 2027 for the May 2028 vote. A disagreement is settled by the labour court, which rules before the procedure opens.
Three useful habits:
- Map it early. List your sites, your legal entities and your real work communities before you count anyone. The company total is not the right starting point.
- Look at the work, not the org chart. Where are the orders given? Where do people eat together? What language is spoken at the coffee machine? These are the signals a judge examines.
- Document your reasoning. If your split is challenged, you will need to show which criteria you relied on.
In short
The TBU is the scope of your social elections, and it is worked out from the reality of the work, not from the statutes. One company can hide several TBUs; several companies can form only one. The four structures above cover most situations, and when in doubt, the split that creates more representation wins.
To place the TBU in the full timeline, read Social elections 2028: the countdown starts. And if your structure looks like one of the cases above and you want to clarify it before late 2027, let's talk.
