Service
Generator Installation
Siting, mounting, exhaust, ventilation and changeover for new and replacement sets, designed around the NEMA boundary noise limit and the loads that genuinely need to stay on.
Symptoms we see
- New set delivered with nowhere prepared to put it
- Replacing an old set in an existing plant room
- Manual changeover you have to go outside to operate
- Set installed but it backfeeds or trips the main
- Exhaust discharging where neighbours can smell it
- Plant room too small, set shutting down on temperature
What's included
- Load survey and essential-loads schedule agreed in writing
- Siting decision against the NEMA boundary noise limit
- Level concrete plinth with anti-vibration mounts and a drained apron
- Exhaust routing and silencing, taken to roof level where required
- Ventilation: intake and discharge louvres sized for the set, not the space
- Changeover: manual switch or automatic transfer switch
- Earthing and protection, and a clear mechanical interlock against backfeed
- Commissioning on load, with readings recorded and handover notes
The work is mostly not the generator
A set arrives on a lorry as a finished machine. What decides whether it works for ten years is everything around it: where it sits, how it breathes, where the exhaust goes, what it is bolted to, and how the load reaches it.
Deciding what stays on
The most valuable hour of an installation is the one spent deciding what is on the essential-loads panel and what is not. It is a subtractive exercise and it is uncomfortable, because the honest answer is usually that not everything can stay on.
An apartment block set that covers lifts, booster pumps, common lighting and the gate is a sensible machine. The same block promising power to every apartment needs several times the set and a service charge to match. Writing that down before anything is ordered prevents the argument that otherwise arrives with the first outage.
Siting against the noise limit, not the available space
On a generous plot the set goes where it is convenient. On a tight one the NEMA boundary limit decides, and the night figure of 35 dB is strict: an open-frame set is nowhere near it, and a standard canopy is not always enough either. Where it is not, the answer is attenuated intake and discharge louvres and a duct silencer, which is building work rather than electrical work and needs to be in the quotation from the start.
Ventilation, exhaust and the plinth
Three things that get cut from budgets and cause most of the callbacks.
Ventilation is sized for the air the set moves, not for the room it fits in. A set starved of air derates itself and then trips.
Exhaust goes where the fumes do not come back in, and in a building with anybody above it that means up. A lateral discharge at podium level puts exhaust into somebody else’s window, and in a lightwell it resonates up every floor.
The plinth is level, drained and isolated. On a sloping site it needs an apron that sheds water away rather than into the canopy, and anti-vibration mounts that stop the set telling the whole building it is running.
Protection and the interlock
A generator connected so that it can feed the grid is a hazard to whoever is working on the line. The changeover must be mechanically incapable of closing both sources at once, and that is an interlock you can see and test, not a procedure written on a wall.
FAQ
▸What is the difference between a changeover switch and an ATS?
A manual changeover needs somebody to walk to it and operate it. An automatic transfer switch senses the outage, starts the set, transfers the load and reverses all of it when the grid returns. If the building has a cold room, a lift, a water pump or a clinic, an ATS is not a luxury.
▸Where can the generator legally go?
Wherever the measured noise at your boundary stays inside the limit, and where the set can breathe. NEMA allows 50 dB by day and 35 dB at night at a residential boundary, with penalties up to KES 350,000. On a tight plot that decides the location, the canopy specification and sometimes the set itself.
▸Does my generator need a permit?
The electrical work must be done by an EPRA-licensed contractor and should come with a certificate of compliance. Larger installations attract a NEMA environmental assessment, bulk fuel storage brings EPRA storage requirements, and county building approval applies to the structure. We tell you which of these apply to your job at quotation, not at commissioning.
▸Why does ventilation matter so much?
A generator rejects a large amount of heat. Put it in a room sized to fit the machine rather than to move air and it recirculates its own exhaust heat, loses output and eventually shuts down on temperature. Louvre area is part of the design, not an afterthought.