Power, Generator and Emergency Lighting in a High-Rise — What Is Really Tested and Who Is Allowed to Test It

The electrical system is the only one in the building on which every other system depends — fire detection, elevators, HVAC, water pumps and building management. When it goes down, everything goes down. And the problem with electricity is that it looks fine right up until the moment it isn't: a panel that has worked for years can hide a loose connection that quietly heats up behind the door — until it ignites. This page is what I actually check in a managed high-rise — not a list of systems, but what is really tested, who is authorised to test it, and what the statement "it worked" conceals.

Electrical maintenance is one link in a broader plan. If you are building it from scratch, it is worth first reading the complete guide to preventive maintenance in an office building, to see how electricity fits into the maintenance year of all the systems.

Inspection of the electrical installation by a licensed testing electrician

The heart of any electrical-maintenance regime is a periodic inspection of the electrical installation by a licensed testing electrician holding a valid licence. The critical point many managers miss: the inspector's licence must match the size of the building's connection. A large connection (industrial connections, high-power complexes) requires an inspector whose licence and authorisation match — an inspector licensed for a small installation is not permitted to sign off on your installation, and such a signature is not legally valid. In Israel, electrical work and its inspection are governed by the Electricity Regulations (Occupational Safety and Health) and by the self-service order — the minimum requirement is supervision and certified approval.

What the inspector actually does

An installation inspection is not "a look around." The inspector measures and tests: earthing continuity and its resistance, operation of the protective devices (fuses, RCDs), conductor insulation, loads versus fuse ratings and cross-sections, circuit marking and identification, and the condition of the panels. It ends with a report listing findings and defects graded by severity.

The most common mistake I see in the field: people receive the report, file it, and do not close out the defects. A report with open defects is not a certificate of soundness — it is a to-do list waiting for a disaster. I once saw a building that received a report with a finding of a loose connection in the main panel, "filed" the report, and a year later dealt with a small fire in that panel. Exactly the same place, exactly the same problem.

High voltage — an entirely separate world

If the building has a transformer room and high voltage, this is an entirely separate field. Work and inspection at high voltage require an electrician holding a high-voltage restricted licence — not every testing electrician is permitted to touch it. The high-voltage cell, the protection relays and the transformer oil tests are a maintenance regime in their own right. It must not be mixed with low-voltage inspection, and you must not settle for a supplier's verbal claim that he "also does high voltage." Demand to see the restricted licence itself — in black and white.

Electrical panel maintenance

Most electrical fires in buildings do not start in a cable inside the wall — they start in the panel. A loose connection or a heating contact point inside a panel is the most common cause. Real panel maintenance therefore includes:

• Tightening connections — terminal screws loosen over repeated heating-cooling cycles; routine tightening is a step that is often missed.
• Dust cleaning — dust is a thermal insulator and a moisture trap; buildup in a panel raises component temperatures.
• Checking fans and ventilation openings — a poorly ventilated panel overheats even without a fault.
• Visual inspection for signs of overheating — scorching, soot, deformed plastic, a burnt smell. These signs always mean something; they are never "a fluke."

"The generator started up" and "the panel looks fine" are the two most dangerous statements in electrical maintenance. Both describe a single moment — not the behaviour under load and over time, which is all that matters.

The RCD — the protection that saves lives

The residual-current device (RCD) cuts the current when there is a leakage to earth — it is what stands between a person who touched a fault and a fatal electrocution. It is a mechanical-electronic component that can "stick" and stop working without anyone knowing. Its testing is therefore neither optional nor deferrable.

There are two levels of testing: pressing the built-in test button — which verifies only basic operation — and a thorough test with an instrument that measures the trip current and trip time against the values required by the standard. An RCD tested only by the button is an RCD you hope will operate — not one you have verified will operate.

Thermographic survey — catching a fire before it starts

This is perhaps the test with the highest return relative to effort in all electrical maintenance. A thermographic survey uses a thermal camera to image the panels and locate hot spots: a loose connection, a heating contact, an unbalanced load between the phases, an overloaded fuse. All of these heat up long before they fail. The naked eye sees nothing; in the thermal camera a hot spot stands out in colour.

The big advantage: in most cases, fixing a hot spot detected in time is a two-minute screw tightening. Compare that to the cost of a panel fire.

The critical condition: the survey must be under full load

A thermographic survey on a de-energised panel or under low load is worthless — a hot spot is revealed only when the current is flowing at full strength. The survey is therefore scheduled for the building's full operating hours, not at night when everything is off and not on the weekend when the offices are empty.

The output is a report with thermal images, the exact location of each hot spot, a severity rating and a recommended corrective action. This is exactly the same preventive logic that separates orderly management from firefighting, as described in the comparison of preventive maintenance and reactive (breakdown) maintenance.

The generator — what "it started up" really hides

The backup generator is the building's insurance for an emergency, and most buildings maintain it at the level of "once a month we start it for a few minutes and hear that it works." That is almost worthless. Running it without load does not prove the generator will carry the building — and it actually harms it over time. A diesel engine that runs cold and unloaded builds up soot in the exhaust pipes and gums up valves — a phenomenon familiar to every generator technician.

The load test — the only real test

The test that determines whether the generator really works is a load test: you apply a real load to it — the building's actual load, or a dedicated load bank connected for the test — and verify that it delivers the required output over time, stable in voltage and frequency, with no abnormal rise in temperature and no collapse. A generator that starts beautifully but collapses under half load — and this happens, I have seen it in the field — will fail at exactly the moment you need it.

The ATS transfer time — a parameter you must measure

The automatic transfer switch (ATS) is what switches between the grid and the generator when the grid fails. The critical parameter is the transfer time — how many seconds the building is dark until the generator comes up and stabilises. You must measure it in practice, not assume it, and verify that it matches the requirements of the critical systems connected to the backup.

Fire-detection systems, elevators and server rooms are especially sensitive to the transfer time. The electrical backup and the systems it feeds should therefore be tested as a single whole — a topic that connects directly to fire and smoke detection system maintenance.

Diesel quality — the fuel that dies quietly

This is the most common reason generators fail to come up when needed, and especially in buildings where the emergency arrives after a prolonged disruption. Diesel that sits in a tank for months breaks down through a physico-chemical process: water accumulates from condensation (a particularly severe problem in Israel with its temperature swings), bacteria and biological sludge develop in the water layer, and the fuel itself oxidises and loses value.

A generator with old, contaminated diesel will start on the clean residue at the top of the tank — and clog filters within minutes under real load. A laboratory diesel-quality test (a sample from the tank) is the part most suppliers drop from maintenance plans, and this is exactly why it must be written explicitly into the contract. "The tank is full" is not "there is good fuel."

Testing electrician's approval for the generator installation

Beyond the generator supplier's mechanical service inspection, the generator installation itself — its connection, earthing, ATS and feed panel — requires inspection and approval by a licensed testing electrician, exactly like the main electrical installation. A service inspection deals with the engine and the mechanics; a testing electrician certifies the electrical installation. Both are needed, and neither replaces the other. In the field, confusion between the two is one of the most common gaps in generator management.

Emergency lighting — the discharge test most buildings do not perform

Emergency lighting is what leads people out when the power fails and the building is dark. Every emergency light fitting contains a built-in battery, and batteries die — often silently, with no external sign.

A fitting that lights up for one second in a manual test may hold for two minutes instead of the required duration — and that is not enough to evacuate the upper floors. The real test is a discharge test: you disconnect the supply and verify that every fitting stays lit for the full required duration — not just that it lights up. Fittings that fail get a new battery or a new fitting. The test is performed by a licensed electrician.

Field experience: in an inspection I carried out in a building that had not undergone a discharge test for two years, about a quarter of the emergency light fittings failed — that is, they were "lit" in a visual check and dead the moment you would need them.

Aviation lighting — the peculiarity of the tall building

In a building over 29 metres tall, aviation warning lighting is required on the roof. This is a system that is easy to forget — it is on the roof, no one sees it from inside, and it has no day-to-day presence. But it is a legal requirement, and a fault in it is both a regulatory and a safety exposure. Make sure it is included explicitly in the annual maintenance plan and does not "fall between the cracks" between the roof and the electrician.

Inspection table: who tests what — and what the test really verifies

Use the table as a baseline and adjust frequencies according to the size of the connection, the age of the installation and the manufacturer's and regulator's guidelines.

What actually goes wrong — recurring, preventable failures

After years of managing this system, the same failures recur again and again — and almost all of them are preventable:

• An inspector's report with defects left open. People receive the report, file it, and do not close it out. The report alone protects no one — closing out the defects does. The solution: for every finding, a due date and a named responsible person.
• A generator that starts but is never tested under load. The short monthly run creates false confidence. Without a load test you do not know whether the generator will carry the building and for how long.
• Old diesel in a "full" tank. The tank is full, the generator starts — and in a real emergency it chokes on sludge and water within minutes. An annual laboratory test is cheap insurance.
• A thermographic survey on a cold or empty panel. A test done at night when the building is empty reveals nothing. Full load is a condition, not an option.
• Emergency lighting that lights up but does not hold. A dead battery lights up for a moment and goes out. Only a discharge test exposes this — and there are no shortcuts.
• Forgotten aviation lighting. On the roof, out of sight, and therefore sometimes out of the plan — until a fault is discovered in an inspection.
• Confusion between the mechanical service inspection and the testing electrician's inspection. Both are needed, neither replaces the other. Many generator suppliers do not provide the electrical inspection — and that is a gap you need to close in the contract.

The electrical system is not a system you maintain when something burns — it is a system you maintain so that nothing burns. That same electrical load also feeds the HVAC and chiller system, so proper planning of the electrical backup directly affects the stability of the entire building. Build the regime, close out the defects, and test under load — not just that "the thing lit up."