Materials that survive sauna heat in gauges and cables

A rating belongs to one part, not to a whole gauge. A sensor, its cable, the case and the screws can each have a different limit. Here's what makers state.

Cables

• Silicone-insulated sauna cable. One seller lists a 3-core silicone cable as suitable for use up to 180°C.¹
• Short periods. The same listing says it's temperature resistant from -60 °C to +180 °C, and for short periods 200 °C.¹
• Temperature class. It says these cables are approved to supply temperature class 'H' up to 180 °C.¹
• A sensor's own cable. One maker lists a heater sensor's cable as 4 meters SIHF 4*0.25 (T 180º).²

Look at the gap between "continuous" and "short periods". Read both numbers.

Sensors

• Overheat limiter. A spare-part sensor lists resettable overheating protection (max. 150 °C).² That's the protection's setting. It isn't the cable's limit, and it isn't the sauna's working temperature.
• Use environment. The same page lists the sensor's use environment as "Interior - wet area".²
• Humidity sensors. A reference page says capacitive types stand up to condensation and temporary high temperatures, while warning about drift and aging.³ The humidity page, how hygrometers work, covers the types.

Control parts kept out of the heat

Some parts of a control system aren't made for sauna heat at all. One maker says the operating environment temperature of its main module should remain between -20°C and 50°C.⁴ The same maker says a door sensor installed higher on the frame can have its magnet and magnet tape affected by temperature.⁴

The lesson: read the rating for each part, and mount it where the maker says.

Cases and fixings

• Frames and screws. One hygrometer fixes into the wall paneling with 3 stainless steel screws.⁵
• Faces. One maker's thermometer has a polished stainless steel frame and a matte polycarbonate background.⁵

That maker's page gives no heat rating for the frame or the face. A material name alone doesn't tell you the limit. Look for a stated temperature.

Softer materials

Silicone rubber offers good resistance to extreme temperatures. It also has low tensile strength and poor wear-and-tear properties.⁶ In plain terms, a silicone cable takes heat but isn't tough against scrapes. Route it where nothing rubs it.

What the sources don't say

The makers' pages don't explain why a particular cheap gauge cracks or fogs. This site won't guess. What a rating does give you is a number to check against the sauna.

Checklist for any gauge or cable

• Is there a stated temperature for each part: the sensor, the cable and the case?
• Does the listing say it's for a sauna or wet area?
• Is the figure for continuous use or for short periods?
• Does the manual name the cable type to use?
• Is a hard-wired heater circuit involved? Leave replacement to a licensed electrician.