Generator repair and servicing for businesses

In short

A standby generator only earns its keep if it starts when the power goes, and regular servicing is what keeps it ready. This guide covers what a technician checks, what a service usually covers and the rules that apply in South Africa, with a tool that writes a clear request for you.

Build your request

Why businesses still keep standby power

Eskom's national supply has been stable since mid-2025, but businesses in Gauteng still lose power for local reasons.^[1][3][4]

Substations and transformers on municipal networks fail, and cable theft and vandalism take areas down. Tshwane has reported a transformer failure at one of its bulk substations with no restoration time available, and Ekurhuleni has linked constant outages in part of Germiston to theft and vandalism at a substation.^[3][4]

Planned maintenance can switch an area off for most of a day, industrial areas included, and in some Eskom-supplied areas of Gauteng load reduction still cuts supply at peak times.^[5][2]

Supply can come back with surges, which is why the City of Tshwane advises switching heavy equipment off during an outage and back on gradually.^[6]

What is it doing?

What a technician usually checks first for each symptom. A failed start is most often a weak starting battery; the rest takes someone on site to tell. If you see smoke or a fuel leak, switch the set off and leave it off until someone has looked at it.^[10]

What is it doing?
What it is doing	What a technician usually checks first	Worth putting in your request
Will not start	The starting battery and its charger, the fuel supply and water in the fuel, and whether the controller is in automatic or shows an alarm.	Whether it turns over at all, any alarm on the controller, and when it last ran.
Starts but will not take the load	The changeover, the controller's settings, and whether the load has grown beyond the set's size.	Its size in kVA, what it is meant to run, and anything added to the site since it was installed.
Shuts down while running	The protective shutdowns: overheating, low oil pressure, overload and low fuel.	The alarm shown, and how long it runs before it stops.
Changeover does not switch	The changeover device, its control wiring and its interlock.	Whether the changeover is automatic or manual, and whether the set itself runs.
Smoke, leaks or noise	Depends on the colour and where it comes from. Leave it off until someone has looked at it.	What you see or hear and where, and that it has been switched off.

What a service usually covers

Follow the manufacturer's manual for your set: intervals are set in running hours or months, whichever comes first, and differ by engine. A service usually covers the following.^[10]

A monthly run under real load, for at least half an hour at about a third of the set's rating or more. A set that only ever idles builds up unburnt fuel.^[10]
The starting battery and its charger, tested under load rather than by voltage alone.^[10]
Oil, filters and coolant at the manual's intervals.^[10]
The fuel: diesel deteriorates in storage and water collects in tanks, so water and sediment are drained and old fuel is cleaned or replaced.^[10]
A load bank test where the monthly runs never reach a meaningful load. This is common practice abroad rather than a South African rule.^[11]
When you ask for servicing, say how many sets, their size, when each was last serviced, and whether you want one service or a regular arrangement.

Build your generator request

Answer a few questions and this tool writes a clear request you can send to any repairer, or post on Headcore. It takes about a minute, and you can change every word.

Companies decide whether to respond from what you write. A request that says what the set is, what it is doing, where it is and how soon reaches the right people; one that says only that the generator is broken mostly does not.

Or go straight to the request form

Why each detail helps

The nameplate: Make, model and size in kVA, so suppliers can check parts.
What it is doing: Will not start, will not take load, shuts down, smoke or leaks, and since when.
How it is used: Standby or prime power, run hours, and what it backs up.
Where and when: The town, access to the site, and when the work can be done.

As often written

Generator broken, need someone urgently.

With the questions answered

Our standby generator will not start. It is a 100 kVA set. The site is in Wadeville. We are without backup power, so this cannot wait.

Rules and paperwork in South Africa

Connecting a generator to a building's wiring is electrical installation work under the Electrical Installation Regulations, 2009. Whoever does it must make sure a Certificate of Compliance (CoC) is issued for that work, and only a registered person may issue one.^[7]

A CoC comes with a test report. The user or lessor of an installation must hold a valid CoC, and an addition or alteration needs a CoC for at least that work.^[7]
The user or lessor of an electrical installation is responsible for its safety and maintenance.^[7]
Registered people hold one of three categories: single-phase tester, installation electrician and master installation electrician. A single-phase tester may only certify single-phase installations, so in practice a three-phase site needs at least an installation electrician. A registered person must show their certificate of registration when you ask.^[7]
In Johannesburg, the emergency services by-law exempts fuel in a stationary engine's own tank of up to 1,000 litres from its fire certificate. In Ekurhuleni, Tshwane and elsewhere, and for anything larger, ask the municipality's fire department.^[8]
Under the Gauteng noise regulations a power generator counts as plant. Where a municipality requires it, installing or replacing one over 10 kW needs 14 days' written notice to it first.^[9]

Questions to ask before work starts

What buyers usually ask the company they choose, before work starts.

Is the changeover interlocked, so the generator can never feed back into the grid? That protects the people working on the network as much as your equipment.
Who will issue the CoC for any work on the wiring or the changeover, and in which registration category?^[7]
What does a service include, and how will you report what you found?
If the set fails between services, who do we call, and how soon can someone come out?
Are parts for this make available locally, or ordered in?

How Headcore helps with this generator

Keep your usual repairer in the mix. Headcore helps you find additional companies that can do this work.

01
Describe what it needs
Start in your own words, a fault or a service. You review the request before anything is posted.
02
Reach companies that do this work
Companies that repair and service generators and serve your area see the job. Each decides for itself whether to respond.
03
Choose who to speak with
Compare how they would approach it, reveal your company only to the ones you choose, and deal with them directly.

Questions buyers ask

Who sees my request?

Companies that do this specific work, within reach of your site. They see the job. Whether they also see your company name is your choice: you can stay anonymous until you pick who to talk to.

What if nobody responds?

Your request reaches companies that do this work within minutes. Each decides for itself whether to respond, so we cannot promise responses. If the work cannot wait, contact your usual suppliers as well.

What does it cost to post a request?

Posting a request is free. A supplier pays one token when it decides your request is worth answering. What you agree about the work is between you and the supplier.

Can I ask for regular servicing instead of a one-off job?

Yes. Say how many generators, how often and what the service should cover. Suppliers respond to the work as you describe it, and you agree the terms with the one you choose.

How often should a standby generator be serviced?

As often as the manufacturer's manual says, in running hours or months, whichever comes first. A set that rarely runs still needs its battery, fuel and coolant checked, and a monthly run under load is the usual practice.

Should I repair an old generator or replace it?

It depends on the engine's condition, how easily parts can be found, and how much the site's load has grown since the set was installed. You can ask for both in one request and let suppliers say what they would recommend.

Do I need a new CoC after generator work?

If the work touches the electrical installation, such as connecting a set or changing the changeover, yes. The section on rules and paperwork above sets out when a CoC is needed and who may issue it. Ask who will issue it before the work starts.

Start with what you know.

Answer a few questions and get a request ready to send, to your own repairer or on Headcore.