Hot tub electrical requirements in Mallorca: amps, lines, boletín

Of everything involved in putting a hot tub on a terrace in Mallorca, the electrics are the part you cannot improvise. The power supply has to be right before the water goes in, and in older fincas and apartments it is the most common reason an installation date slips. This guide covers what a hot tub needs electrically, what each series draws, how contracted power affects you, and what our electrician looks at on the first visit.

A dedicated line, nothing shared

Every hot tub and swim spa needs its own circuit from the main consumer unit (the cuadro eléctrico):

• Its own circuit breaker sized for the model.
• Its own 30 mA residual current device (RCD, in Spanish a diferencial), separate from the house's.
• A hard-wired connection into the tub's control box, with a weatherproof isolator near the tub so it can be cut off without going indoors.

A tub cannot share a circuit with the kitchen, the pool pump or the air conditioning. Shared circuits trip at the worst moment, usually when the heater and the oven run together on a December evening.

Amps by series

The supply each model needs, at 230 V single-phase:

• Essential: Cala 3, Cala 5 and Rodona 6 run on 16 A with a 3 kW heater and one pump. The Cala 6, with two pumps and a 4.5 kW heater, needs 20 A.
• Premium: Serra 3 needs 20 A. Serra 5 and Serra 6, with two pumps, a circulation pump and a 4.5 kW heater, need 25 A.
• Signature: Mar 5 and Mar 7 with three pumps and a 6 kW heater need 32 A.
• Swim spas: Nedar 4.3 and Nedar 5.2 need 40 A. The Nedar 5.9 Dual, with two heated zones and 11 kW of heating, needs 50 A.

These are the ratings for the breaker and cable, not the continuous draw. The control system manages the load, so the heater pauses when both jet pumps run at high speed. A Serra 5 heating with the circulation pump running draws about 4.6 kW, and for most of the day it draws almost nothing.

Contracted power: potencia contratada

In Spain households choose and pay for a maximum power, the potencia contratada, shown in kW on every bill. Draw more than that at any moment and the meter's limiter cuts the whole house. Common values are 3.45, 4.6, 5.75 and 6.9 kW for flats and townhouses. Villas with air conditioning and a pool pump are often on 9.2 or 10.35 kW, and larger properties on three-phase have more.

The question is not whether the tub fits within the contract on its own. It is whether the tub plus everything else that runs at the same time fits. A rough guide:

• An Essential tub adds up to about 3.5 kW at peak. On a 5.75 kW contract with an induction hob and a split air conditioner running, that is tight. On 6.9 kW it is comfortable.
• A Premium tub adds up to about 5 kW. We usually suggest at least 6.9 kW for a house that also cooks on electricity.
• A Signature tub adds up to about 6.5 kW. Plan on 9.2 kW or more.
• A swim spa adds 8 to 11 kW. Nearly every swim spa installation involves raising the contracted power or moving to three-phase.

Raising the contracted power is done through your electricity retailer. Up to the limit your existing certificate allows, it is a remote change on the smart meter, usually within a week, and costs a few euros a month more on the fixed part of the bill. Going beyond the certificate needs a new one from an electrician, which is sensible to combine with the new line for the tub.

Single-phase or three-phase in villas

Many fincas and larger villas have a three-phase (trifásica) supply, installed years ago for a well pump or heavy air conditioning. Hot tubs are single-phase appliances, so the electrician connects the tub to the phase carrying the least load and the house stays balanced. The Signature models and all the swim spas can also be wired so that the heater and the pumps sit on different phases, which spreads the load and is the normal way to connect a Nedar 5.9 Dual. If you only have single-phase at 5.75 kW and you want a swim spa, budget for a supply upgrade and allow extra time for the distributor to action it.

Cable runs and what they cost

Distance from the consumer unit to the tub decides the cable size, and cable size decides the cost. A 16 A circuit over a short run needs 2.5 to 4 mm² cable; 25 A over 20 m needs 6 mm²; 32 A typically 10 mm²; a swim spa 16 mm² or more. Longer runs need thicker cable to limit voltage drop, which is why price rises with distance. The cable runs in rigid conduit on a wall or buried in a trench in the garden.

The price builder on this site uses two bands, both including RCD, breaker, cable, isolator, labour and certificate:

• New line up to 15 m: €550–750.
• New line 15–30 m: €850–1,200.

Longer runs, a sub-board in an outbuilding or a trench across a paved courtyard are quoted after the visit. Raising the contracted power is paid to your retailer.

No outdoor sockets, no extension leads

Spanish wiring regulations treat the area around a spa like a pool zone. Within it there are no ordinary sockets, and anything electrical has to be hard-wired, protected and rated for wet conditions. A full-size hot tub never plugs into a garden socket. Inflatable plug-in spas are a different class of appliance, which is why they take a day to warm up. Extension leads from the house are out of the question, as are mains-voltage garden lights or speakers within reach of the water. Low-voltage lighting is fine.

The certificate: the boletín

For a new dedicated circuit of this size the electrician issues a Certificado de Instalación Eléctrica, which everyone on the island still calls the boletín. It records the circuit, the protection and the test results, and it is registered with the regional industry department. You need it to raise the contracted power beyond the old certificate, and your insurer may ask for it after any incident on the terrace. The line price above includes it. An installer who offers to connect a tub without one is the wrong installer.

Swim spas: plan the power first

A swim spa is an electrical project first. The Nedar 4.3 at 7.5 kW and 40 A is at the level of a small car charger; the Nedar 5.9 Dual at 11 kW and 50 A exceeds the whole contracted power of many homes. In winter the two heated zones work hard, which is where the €180–260 monthly running figure comes from. The sequence that avoids delays: check the supply, raise the contract or switch to three-phase, run and certify the line, then book the crane. The other way round leaves 8 tonnes of swim spa sitting cold on a base for a month.

What the installer checks on the visit

The electrical part of the site visit comes down to a short list:

• The consumer unit. Condition, spare ways, and whether the main switch and RCDs are modern. In fincas from the 1970s and 1980s the board is often the first thing that needs attention.
• The bill. The potencia contratada and whether the supply is single or three-phase, both printed on it.
• The route. How far the tub site is from the board, and whether the cable can go through a wall, along a facade or needs a trench.
• The earth. Older rural properties sometimes have a poor or missing earth. A tub with a weak earth is not safe and the RCD will not behave correctly.
• Solar and generators. Inverters and generators change how the circuit is protected and how the tub should be scheduled.
• The isolator position. Visible from the tub, reachable, out of the splash zone.

Send a photo of the open consumer unit and of a recent bill before the visit and most of this is answered in advance.

Our take

Electrics are the one part of a hot tub installation where cutting corners is both unsafe and false economy. Budget €550–1,200 for a new dedicated line unless you already have a certified outdoor circuit of the right rating, check your potencia contratada before you order, and treat a swim spa as a power upgrade with a pool attached. The price builder on this site includes the two electrical bands so you can see the installed figure for your model, and a photo of your cuadro on WhatsApp tells us most of what we need to know.