Aydınevler, Maltepe

The call from Aydınevler usually comes in the evening: 'We filled the jacuzzi, pressed the massage button and the whole home lost power. The RCD in the panel has dropped. We reset it; everything is normal as long as we don't turn the jacuzzi on. Last month it tripped once by itself after a long bath.' Every part of this description says something. That the RCD tripped, not a breaker, shows the problem is neither overload nor a short but part of the phase current not returning on the neutral and going to earth. The RCD dropping exactly as the pump starts says the leakage is on the pump's motor side. Tripping by itself after a long bath shows the leakage is not fixed but grows with accumulating water: water seeping from the seal collects in the terminal box and with limescale forms a conductive bridge. The whole home going dark is useful information too: the jacuzzi has no RCD of its own and sits on the home's shared 30 mA RCD. The first job is not to run the jacuzzi again, never to bridge the RCD, and not to climb into the wet tub and try to open the front panel by hand.

A jacuzzi pump is a compact machine with its motor and water body on the same shaft. What separates the water side from the motor side is the mechanical seal turning on the shaft and bearing against a fixed face. The seal faces run on a very thin water film; over time they wear, limescale gets between them, and the vibration while the pump runs speeds up wear. Istanbul's hard water is decisive here; each time the tub is drained the water left in the pump evaporates and limescale builds up. When the seal starts to leak, water moves along the shaft towards the motor. On most pumps there is a small terminal box on the bottom or side of the motor body where the supply cable and capacitor connect. When water reaches this box a damp, limy surface forms between the terminals and between a terminal and the metal body. A leakage current of a few milliamps starts flowing from the phase terminal to the metal body; if the body is earthed by the PE conductor, the current goes to earth. When the leakage nears the 30 mA RCD's trip threshold, the RCD drops. The more water, the larger the leakage; that is why the same jacuzzi runs fine one day and trips in the first second the next.

The point to read correctly here is this: the RCD dropping is not the fault, it is protection working. The fault is inside the pump. The real danger is a bathroom where the RCD does not drop. In some installations an RCD that keeps tripping is bridged as 'faulty', removed, or replaced with a 300 mA fire RCD; in some old bathrooms no PE was ever connected to the pump body, or the PE has broken somewhere. Then the leakage current finds no path to earth and waits on the pump's metal body, on the tub frame touching it, on metal pipework and in the water in the tub. A wet, bare body carries that voltage through a very low resistance; the bathroom is where electric shock is most lethal. A jacuzzi also has a heater and on some models an air blower. If the heater element's sheath has cracked or the blower has taken on moisture, the same symptom can come from them; so the survey does not stop at the pump. Nothing is replaced until the leaking part has been separated out one by one.

The survey starts at the panel. Which breaker feeds the jacuzzi, which RCD it sits under, the RCD type and trip threshold are read; the RCD is confirmed to really open with its test button. Then the connection is checked: plugged into a socket under the tub, a fixed connection, where the isolator is. After the line is switched off at the panel and dead is proven by measurement, the tub's front service panel is opened. Pump, heater and blower if fitted are inspected by eye: water traces around the shaft, limescale crust, rust, water in the terminal box, green copper, a blackened capacitor. Then each part is disconnected and megger-tested at 500 V DC for insulation resistance between conductors and metal body. In a healthy motor and heater this is in the megohms; in a wet terminal box or a winding that has taken on moisture it drops noticeably. That separates which part is down. Finally PE continuity is measured: is there a low-resistance unbroken path from the pump body to the PE bar in the panel. Whether the tub frame and metal pipes are connected to this path is checked too.

The first step of the repair is the source of the leakage. If the seal leaks, the pump's mechanical repair or replacement is the jacuzzi service's job; an electrical repair without a new seal only buys time. On the electrical side the wet terminal box is opened, dried, and cleared of limescale and rust; terminals and the box gasket are renewed if damaged, a bulged or blackened capacitor is replaced with one of the same value, and insulation resistance is measured again after the repair. If the heater or blower tested low they are handled the same way. The supply connection is moved out of the drip path: not above or below the pump but at a height and to the side the water cannot reach, into a closed, gasketed IP65–IP67 box with glanded entries. The cable enters the box from below so dripping water cannot follow it in. If the tub is plugged into a socket underneath, a fixed connection replaces it; a two-pole isolator goes outside the bathroom zones in an easy-to-reach place. The jacuzzi is separated from the home's shared RCD and fed from its own line under its own breaker and its own 30 mA RCD; that way a leak does not black out the whole home and which appliance tripped is clear at once.

The last step is local supplementary equipotential bonding. The pump's metal body, the tub's metal support frame and reachable metal water pipes are connected with 4 mm² green-yellow copper to the bathroom's bonding point or directly to the line's PE conductor; connections are made with clamps or lugs so they will not loosen or corrode. The purpose is to stop a dangerous voltage difference forming between touchable metal parts in the bathroom during a fault, in the time until the RCD opens. Supplementary bonding does not replace the PE conductor, nor the RCD; the three work together. After the repair the line is re-energised, the RCD tested with its button and where possible an RCD tester, the jacuzzi run with water, and the standing leakage on the line measured with a leakage clamp; it must stay well below the RCD's threshold. Removing and refitting the tub, tiling and silicone work and plumbing leaks are the plumber's job. How many metres of new line, which box and which RCD are needed are written on site at the survey, not guessed on the phone.