On 230 V single-phase, a garage can supply one workstation at a time: one mechanic, a 1/2" impact wrench, tyre inflation and a blow gun. Above roughly 2.2 kW of motor power, single-phase reaches its limits, and as soon as two mechanics work at once you generally need 400 V three-phase.
Many small workshops set up in former retail units are in this situation. For a full workshop setup, see our compressor for garages page. This article answers one question only: what can you do with 230 V?
What single-phase really allows
A single-phase motor draws a lot of current at start-up. That is why compressors that plug into 230 V stay small, around 2.2 kW at most on a dedicated circuit. Our article 230V or 400V piston compressor details the power thresholds and the electrical checks.
In a garage, the question becomes: can this small compressor keep up with my tools?
The calculation for one mechanic
Typical figures, to check against your tool manuals: 1/2" impact wrench about 300 l/min at 6.3 bar, tyre changer about 150 l/min at 8 bar, tyre inflator about 100 l/min.
- Hungriest tool: the impact wrench, 300 l/min.
- It works in bursts and the receiver covers the peaks, so it is counted at 50%: 150 l/min.
- 25% margin: 150 × 1.25 = about 190 l/min.
- Pressure: 8 bar at the tyre changer, plus about 1 bar of losses, so 9 bar at the compressor.
Compare these two figures with the free air delivery shown on the single-phase compressor's data sheet, at working pressure. The displacement figure, often put forward, is higher and does not tell you what reaches the tool.
The role of the receiver
On single-phase, the receiver does much of the work. Example with a 100 L receiver falling from 10 to 8 bar, an assumption to adapt to your machine:
- Air available: 100 × (10 - 8) = 200 litres.
- Impact wrench at 300 l/min: 200 ÷ 300 = about 40 seconds of tightening on the reserve alone, before counting what the motor produces meanwhile.
That is enough to remove the nuts on a wheel, then let the compressor build pressure again. To estimate the right receiver for your tools, use the air receiver size calculator.
The calculation for two mechanics
- Two impact wrenches counted at 50%: 2 × 150 = 300 l/min.
- 25% margin: 300 × 1.25 = 375 l/min at 9 bar.
The need doubles, and a small single-phase compressor struggles to keep that pace: pressure drops, the motor runs without rest and overheats. From two mechanics upwards, three-phase is the lasting solution.
Three options depending on your situation
Stay on 230 V with a single workstation. Choose a machine whose data sheet clearly states 230 V single-phase, with the largest receiver possible, on a dedicated circuit. Avoid extension leads and multi-socket adaptors.
Switch to three-phase. This is the answer if the workshop is growing. You then have access to machines such as the E 75, a 0.9 m³/min piston compressor on a 180 L receiver, in 8 or 12.5 bar, or the K 75, a 4-in-1 screw compressor with a 420 L receiver and built-in dryer. Both connect to 380 V three-phase, like all our screw compressors.
Look at the E 40. Our E 40 is a 4 kW piston compressor on a 100 L receiver. At this power, single-phase is at its limit: ask us for its voltage and pressure before ordering.
Pitfalls of a single-phase garage
Three-phase may already be there. Some vehicle lifts and tyre changers run on three-phase. If yours do, the supply already reaches the board: an electrician will check the available capacity.
The breaker that trips at start-up. The compressor needs its own circuit, with a cable size and protection suited to the motor's inrush current. Do not put it on the same circuit as the lift or the battery charger.
The compressor that never stops. If it runs non-stop as soon as you work, it is too small for the job. A piston compressor needs rest time: in the long run, it overheats and wears.
Running cost. The compressor electricity cost calculator gives an order of magnitude based on your operating hours.
List your tools in the configurator, or send a photo of your fuse board with your quote request: we will tell you which solution fits.
For your trade: Compressor for garages.