Smart toilets are electrical appliances, and the electrical side of the installation is where most failed installations go wrong — usually because the socket was never planned. This guide covers what Europe and North America each require, and what you can expect in running costs.

Europe: 220–240 V earthed, dedicated circuit preferred

European shower toilets and electric bidet seats connect to a 220–240 V earthed socket, ideally on a dedicated circuit. Three rules from European specialists apply everywhere:

  • Never plug into a multi-socket extension or adapter. Every major brand we reviewed states this explicitly — it is the most common electrical failure cause.
  • Socket placement is regulated. French standard NF C 15-100, for example, requires bathroom sockets more than 60 cm from shower or bath. Always have electrical work done by a professional who knows the local code.
  • Plan the socket before tiling. For wall-hung toilets, the cable typically routes behind the support frame — much easier before the wall is closed.

North America: 120 V GFCI outlet within reach

North American units are 120 V and require a GFCI-protected 3-prong grounded outlet within reach of the power cord — typically about 1 m (3 ft) from the toilet. Cord lengths are standardised at about 1.2 m (4 ft), and GFCI is code-required for new bathroom outlets. Practical guidance from US specialists:

  • Dedicated circuits are recommended but not mandatory; avoid sharing a circuit with high-power appliances (washing machines) to prevent flicker or tripping.
  • A 15-amp circuit is sufficient; the wash heater peaks briefly (roughly 600 W for tank-type, up to ~1400 W for tankless) only during hot washes — a few minutes a day.
  • An extension cord is acceptable only if it is a grounded 3-prong cord rated for the load — but a properly placed outlet is the correct solution.

For consumption reference, ENERGY STAR's appliance data (energystar.gov) and European measurements (BSI-certified test data) put a full-featured unit at roughly 0.5–1 kWh per day — around €45 per year at €0.25/kWh — with eco modes cutting that by 30–50%.

What happens in a power cut?

Nothing alarming: the toilet remains fully usable as a normal toilet — flushing still works, either manually or via a small backup battery on some models. Only the electronic functions (wash, dryer, heated seat) pause until power returns. There is no risk of overflow or valve failure from a power loss.

What OtterMax ships

Platforms match their markets exactly: the ETW and ES platforms are built for 220–240 V European supply; the NS2401 is a 120 V unit with ETL/cETL listing for North America. Cables are sized to reach a standard outlet position, and the technical file includes the electrical data sheet for your installer. The FAQ page has the quick version of these requirements.

Frequently asked questions

Can I use an extension cord?

European practice: no — never a multi-socket extension. North America: only a grounded 3-prong cord rated for the load, and only as a short-term measure; a dedicated outlet is the correct installation.

Do I need a dedicated circuit?

Recommended, not mandatory, in both markets. The main risk on a shared circuit is lights flickering when the tankless heater fires — avoid sharing with washing machines or other high-draw appliances.

Who should do the electrical work?

A qualified electrician, always. Socket placement rules (such as French NF C 15-100) exist for a reason, and an incorrect installation voids warranty and insurance.

How much will it cost to run?

Typical full-featured unit: 0.5–1 kWh/day (about €45/year at EU average rates), with eco modes reducing that by 30–50%. Heated-seat eco mode heats only while someone is seated.