The Problem: Machinery That Couldn't Run
A joinery business had invested in workshop machinery that needed a three-phase supply. The site didn't have one.
This is a more common blocker than people expect. Plenty of commercial units, converted farm buildings and rural workshops were only ever wired for single-phase domestic-style loads. The moment a business brings in serious woodworking plant — panel saws, spindle moulders, extraction systems, larger planers — that supply stops being adequate. The machinery sits there, capital tied up, not earning.
The conventional route is to ask the network operator for a three-phase upgrade. That is sometimes the right answer. But depending on the site, it can mean a long lead time, groundworks, and a quotation the business has no control over — and none of that is within your gift to speed up.
The Approach: Generate The Supply You Haven't Got
Where a grid three-phase upgrade isn't practical, a correctly sized generator can be the three-phase supply rather than merely a backup for one. That is a different design brief, and it changes how you size the set.
Sizing for start-up, not just running load
Workshop machinery of this type is dominated by induction motors, and induction motors draw substantially more current starting than running. Size a set against the running load alone and it will nuisance-trip or sag the voltage every time a large motor is switched in — particularly if something else is already turning.
So the sizing conversation has to cover:
- The realistic worst-case combination of machines running together, not the nameplate total
- Start-up surge for the largest motor starting onto an already-loaded set
- Extraction and ancillaries, which are easy to forget and rarely switched off
- Headroom for what the business plans to add next, rather than sizing exactly to today
A 23kVA three-phase Deutz set was specified on that basis — enough capability to start and run the workshop properly, without paying for and fuelling capacity that would never be used.
Why this matters: an undersized generator doesn't fail obviously — it fails intermittently, under load, usually mid-cut. Oversizing has its own penalties: higher cost, poorer fuel efficiency, and prolonged light-load running that isn't good for a diesel set. Getting it right is the whole job.
Changeover: one set, two duties
Because the generator was being installed anyway, it made sense for it to earn its keep twice. The changeover arrangement means the same set that powers the workshop machinery can also carry the wider property when the incoming supply is lost.
That turns a single-purpose purchase into genuine business resilience: the machinery gets the three-phase supply it needs to work, and the property gets standby cover it didn't have before — from one installation, one commissioning, one certificate.
Installation, Commissioning & Certification
Supplying a generator is the easy part. What determines whether it's still reliable in five years is the installation around it — and that's electrical contracting work, not plant hire.
- Generator positioned, connected and integrated with the site's distribution
- Changeover arrangement installed so switching between sources is controlled and unambiguous
- Full commissioning under load, rather than a start-up test on no load
- NAPIT-certified with the documentation insurers and building control actually ask for
The Result
The workshop machinery runs on a proper three-phase supply, on a site that never had one. The business isn't waiting on a network upgrade to start using equipment it has already paid for. And the same installation gives the whole property backup power it previously lacked.
Generator work is a specialism, wherever the site is. Load assessment, sizing for motor start-up, changeover design and certified commissioning are the same disciplines whether the set is powering a joinery workshop in the south of England or a croft with no grid connection at all. It's the reason we're comfortable being called out well beyond our doorstep.