What to Know About Your Electrical Installation

Is your installation matched to the load you now put on it?

A large share of Istanbul flats were built in years when today’s electrical load was not even imagined. Back then a home ran a fridge, a television and a few lights. The same flat now runs air conditioning, an electric hob, a dishwasher, a boiler, a water heater and a row of devices permanently on charge — most of them at the same time of day.

The problem is usually not the appliances but the cross-section of the cable feeding them and the way the circuits are divided. In a 20 to 30 year old installation every socket in the flat may sit on a single circuit; in that case a tripping fuse is not a fault but the system working correctly — the protection is doing its job. The right response is to redistribute the circuits and increase the cable size to suit the current load. Our electrical installation page describes what a rewire covers.

Why do fuses trip? Three causes and one dangerous fix

A tripping fuse is the shared symptom of three entirely different conditions. Any intervention made without separating them is guesswork:

• Overload: the circuit cannot carry the total current of everything connected to it. It usually trips when particular appliances run together, and it repeats predictably.
• Short circuit: live and neutral have made contact. It trips instantly and hard, often the moment a particular plug goes in.
• Earth leakage: current is escaping the intended path, usually into moisture or through failed insulation. The RCD trips while the breaker often does not, and it gets more frequent in damp weather — a classic sign.

We separate the three by measurement: splitting the circuit to find the offending leg, then testing insulation resistance and leakage current. Finding the cause before replacing anything is the entire job.

The most dangerous “fix” here is replacing a tripping fuse with a higher-rated one. That does not solve the problem; it disables the protection. The fuse protects the cable — fit one rated above what the cable can carry and the circuit now heats up without ever disconnecting, which is a direct fire risk. Ignoring a fuse that keeps tripping is like removing the bulb behind the oil warning light.

What is earthing, and why is it non-negotiable?

Earthing gives fault current a safe path to follow. Without it, the metal casing of a failed appliance becomes live and the current passes through whoever touches it. An earth pin in the socket does not prove there is an earth conductor behind it — in older buildings it is common to find that an earthed socket was fitted during a refurbishment while the conductor was never run.

That is why earthing is confirmed by measurement rather than by eye. We measure earth resistance and give you the result in writing. Where the earth is missing, no protective device — the RCD included — can work the way it was designed to.

What does an RCD do, and how do you test it?

A residual current device continuously compares the current flowing out with the current returning. Any difference means part of it is leaving the circuit — for example through a person to earth — and the device disconnects within milliseconds. That is why it is the single most critical component in the board.

In homes, shock protection uses a 30 mA device. The 300 mA versions target fire risk rather than people, and one does not substitute for the other. Giving wet rooms and outdoor sockets their own residual protection also stops one fault from taking the whole flat dark.

The test button on the device is not decorative. Press it once a month and watch it trip. If it does not trip, it is not protecting anything and must be replaced immediately. Our work on the board itself is covered on the consumer units and fuse boards page.

Why do cable size and circuit separation matter?

Cable cross-section sets how much current a circuit can carry; circuit separation sets how much of the building one fault takes out. Together they define both the safety and the usability of the installation. Common practice runs roughly as follows:

• Lighting circuits are adequately served by 1.5 mm² cable.
• Socket circuits use 2.5 mm².
• High-load appliances such as air conditioning, electric hobs and water heaters take 4–6 mm² on their own circuit from the board.
• Rooms where load concentrates — kitchens and bathrooms — need their own circuits; one socket circuit in a kitchen is not enough for today’s appliances.
• Lighting and socket circuits are kept separate, so a socket fault does not leave the home in the dark.

The most common mistake when adding a circuit for a new appliance is extending from the nearest existing socket. That quietly increases the load on an existing circuit and surfaces the problem somewhere else a few months later. We run dedicated circuits as part of sockets, switches and new circuits.

What difference does a tidy consumer unit make?

An unlabelled board costs time at every fault. If nobody knows which breaker feeds what, even a small job means shutting down the whole property. Worse, in an emergency finding the right breaker takes seconds, and those seconds count.

When we replace a board we separate the circuits, label every way, and leave a schedule inside the board showing which breaker serves which room. Older boards with ceramic fuses should be replaced outright: they were never designed for today’s load profile, and they offer neither residual current protection nor any selective disconnection.

Which electrical warning signs need immediate attention?

None of the following belong in the “I will get it looked at eventually” category. Each indicates heating or loss of insulation somewhere in the installation:

• A socket or switch that runs warm, discolours or deforms.
• A smell of burnt plastic — if the source cannot be found, the circuit should be switched off.
• Sparking when a plug goes in or comes out.
• A tingling sensation when touching the metal body of an appliance; this is the classic symptom of an earthing problem.
• Lights dimming noticeably when a large appliance starts.
• An RCD that trips repeatedly, particularly in wet weather.

Where any of these appear, we find the source by measurement. Under electrical fault finding and repair we usually attend urgent faults within Istanbul the same day. We cover the causes of hot sockets in why sockets get hot, and power going out in only part of the house in power out in part of the house.

In what order should electrical work be done in a renovation?

The most expensive mistake in a renovation is thinking about the electrics too late. A missing socket noticed after the walls are closed, plastered and painted means opening the whole job back up.

The correct order is: settle furniture and appliance positions on paper, set socket, switch and lighting points against that layout, run first fix (channels, conduit and cable), close the walls, and complete second fix (sockets, switches and fittings) last. Followed in that order, the wall opens once.

The points most often forgotten at the planning stage: USB sockets beside beds, the socket and cable route behind the television, how many sockets sit above the kitchen worktop, mirror lighting in the bathroom, and outdoor sockets for the balcony and entrance. On the lighting side, colour temperature and switch grouping need deciding in advance — we cover that on the lighting and LED systems page.

Who should do the work, and what should you ask?

In electrical work, a cheap quote is usually cheap somewhere you cannot see: in the cable cross-section, in the grade of the breakers and sockets, in running cable across the surface instead of cutting channels. When taking quotes we suggest asking: what cable size and make will be used, which protective devices go in the board, will earth resistance be measured and provided in writing, how long the workmanship guarantee runs, and what documentation you receive at handover.

Our survey and written quote are free and carry no obligation. During the survey we tell you separately which work is genuinely necessary and which can wait.

How often should an electrical installation be checked?

An electrical installation does need maintenance, but not much of it:

• Monthly: press the RCD test button and confirm that it trips.
• Every six months: check sockets and switches for heat, discolouration and looseness.
• Annually: have board connections checked for tightness and the labelling checked for accuracy.
• After a renovation, an air conditioning installation or a major appliance purchase: reassess the load on that circuit.
• On installations over 20 years old: have earth and insulation resistance measured once; the result becomes a reference for the rest of the installation’s life.