Single phase or three phase floor grinder: which power supply?

The power question comes up on almost every floor grinder enquiry: does the job need single phase or three phase? The honest answer is usually single phase, and the reason is simple: it is the supply already available on site.

What is the real difference between single phase and three phase power?

Single phase power, the standard 230 V supply found in almost every building, delivers power through one alternating current waveform. Three phase power, typically 400 V, delivers three overlapping waveforms and is normally found on larger industrial sites, workshops and some commercial units with a dedicated three phase connection installed.

Why does single phase cover most jobsites?

Because single phase 230 V is what almost every building and site already has. A domestic refurbishment, a shop fit-out, a school corridor or a housing site rarely has a three phase supply run to the work area, while a 230 V socket is standard on any job. Specifying a three phase machine for this kind of work means either finding power that is not there or hiring a generator, both added cost and hassle for no real gain.

Where does three phase actually make sense?

Three phase earns its place on very large, continuous areas run for extended hours, such as a big warehouse slab, a distribution centre floor or an industrial unit already wired for three phase equipment. In that context the supply is already available, the floor area is large enough to justify a heavier-duty machine, and sustained high-load running benefits from the more even power delivery three phase provides.

What does a brushless motor bring on 230 V?

A brushless motor has no carbon brushes to wear. On 230 V, the available power depends on the site supply: check it before choosing between single phase and three phase.

How to size the extension lead and the breaker?

The basic rule is simple: the longer the extension lead, the more generous the cable cross-section must be to avoid a voltage drop at the end of the line. A lead that is too thin or too long for the machine’s power causes a loss of voltage on arrival; the machine compensates by drawing more current, which can trip the breaker or overheat the cable.

What should be checked before committing to a single phase setup?

Check the circuit, not just the socket. A single phase supply that also feeds a dust extractor, task lighting and a battery charger on the same run can trip under combined load even though the grinder alone would run comfortably. Confirming the available circuit capacity, and running the extractor and grinder on separate circuits where possible, avoids a nuisance trip halfway through a slab that then has to be restarted and re-levelled from a stop line.

How should the choice actually be made?

Start from the site, not the spec sheet. If the job runs off standard 230 V, a single phase grinder of adequate rating handles sustained floor grinding. Three phase stays a sensible option specifically for very large, continuous industrial areas already wired for it and run for long uninterrupted hours. Pair either setup with proper on-tool dust extraction: the extraction system, not the phase count, is usually the detail that decides how clean and how fast the job actually runs.