Sauna electrical safety

Sauna electrical safety covers the installation and use of electric heating in the sauna — the heater, its control unit, the supply wiring, and the protective devices — where the rule that governs everything is the oldest in electrical practice: fixed electrical work is done by a qualified electrician, to the applicable installation code, and the bather's own duties are inspection and care, never modification. The electric sauna is a safe appliance when installed and used within its rules; the statistics of sauna fires place the causes of most electric-cabin incidents exactly in the places this article lists — overlong running, misplaced thermostats, laundry over the heater and ageing installation.

The installation

The electric sauna is an electrical installation and is treated as one (see Sauna electrical installation). The heater cable is sized and routed for the circuit, the connections are made in the junction box the heater manufacturer specifies (Sauna cable), the heater is earthed (Electrical earthing in a sauna) and protected by the residual-current device that the code requires for the sauna circuit, and the enclosure and IP ratings of the controls match the damp environment of the cabin (IP rating in a sauna); the Sauna control unit and its timer, thermostat and sensor are mounted according to the manufacturer's pattern, including the critical placement of the thermostat so that cool inlet air cannot bleed heat readings from it — the misplacement identified in the safety agency's reviews of electric saunas. All of this is professional territory: the encyclopaedia's rule, written through every article of this batch, is that a sauna electrical installation is designed and signed by a certified electrician and inspected at the intervals of the local routine (see Sauna maintenance schedule and Sauna heater inspection), and the DIY handbook closes at the junction box (Electrical standards for sauna equipment).

The heater in use

The heater itself (Electric sauna heater) is a high-power heating appliance with a duty cycle: the relevant appliance standard for sauna heaters limits the continuous on-time, with the commonly cited figures of a maximum twelve continuous hours and a mandatory rest period — the figures relayed in the Finnish Sauna Society's fire-safety article — and the safety agencies' surveys of commercial saunas found the limits routinely exceeded: the cabin operator's duty is the timed control (Sauna timer, Sauna control unit, Sauna thermostat) that closes the heater at its limit. In use, the rules are the fire-safety ones of Sauna fire safety: nothing whatsoever above or around the heater — no laundry, towel or cloth anywhere over the stones; the heating-on ritual of checking the cabin before switching on, including the corners where a stray garment hides (Safe remote start extends the same check to the phone-triggered heater: the remote start must be arranged so that the cabin is empty and clear when the element fires); and the clearances of the appliance's installation sheet around and above the heater, with the Heat shield and guard (Heater guard) where the layout or the children require them (see Burn prevention in a sauna and Sauna burns).

Protection and failure behaviour

The protection architecture of the electric cabin: the residual-current device (RCD) on the sauna circuit saves against earth faults in a damp room; the thermal protection built into the heater and the control unit's over-temperature sensor close the element if the room overheats; and the Sauna emergency shut-off — the readily reached control that kills the heater in an emergency — is part of every commercial and home installation, wired so that it actually disconnects the power and not merely the display. The behaviour at power failure belongs to the same review: a heater that is simply switched off cools safely, but a heater controlled by a timer that restarts after a mains interruption resumes on an unattended, hot, possibly abandoned cabin — the reason the safer control schemes fail closed rather than resume, and the reason the remote start (Safe remote start) and the timer are specified with that behaviour in mind (see Sauna power failure).

The facility and the user

For facilities and their staff, the electrical side is scheduled work: the periodic inspection of the installation and the heater (Sauna heater inspection), the records, and the training that keeps a hot, empty, running cabin from becoming the day's most expensive smell (see Sauna supervision, Sauna risk assessment and Sauna fire safety). For the private bather, the summary is an even shorter list: the electrician signs the work, the manual's duty limits and clearances are kept, the cabin is cleared before heating and checked after, the heater's on-time obeys its timer, and any crack, smell, trip of the RCD or discoloured cable is a stop-and-call event, not a "keep an eye on it" one (see Sauna electrical installation, Sauna emergency shut-off and Sauna safety).

See also

• Electric sauna
• Sauna fire safety
• Sauna heater inspection
• Residual-current device for a sauna
• Sauna emergency shut-off

References

• The Finnish Sauna Society. "Saunan paloturvallisuus" [Sauna fire safety]. Suomen Saunaseura ry, Helsinki. sauna.fi – Saunan paloturvallisuus
• Hussain J, Cohen M. "Clinical effects of regular dry sauna bathing: a systematic review." Evidence-Based Complementary and Alternative Medicine 2018:1857413, 2018. doi:10.1155/2018/1857413