What is the temperature rise test limit for a float level controller?

I. Terminal Temperature Rise (Mass Production Factory Judgment Standard)

Bare Copper Terminals: ≤60K

Tin-plated Copper Terminals (Standard Float Switch): ≤45K (National Standard Acceptance), Strict Safety Regulations ≤40K, Maximum Terminal Temperature ≤70℃ at 25℃ Ambient Temperature

Silver-plated Contact Terminals: ≤70K

II. Housing / Touchable Junction Box Housing

Ordinary Plastic Housing: ≤30K (Not hot to the touch)

Aluminum / Metal Junction Box: ≤45K, Explosion-proof BT4/T6 Housing Additional Restriction: Surface temperature must not exceed the maximum surface temperature of the explosion-proof group (T6≤85℃, T4≤135℃)

III. Temperature Rise of Internal Key Components

1. Passive Reed Switch Type (Mainstream Double Float Switch, No Coil Self-Heating)

Contact Long-Term Full-Load Temperature Rise: **≤35K**; Reed Glass Tube Body Temperature Rise: ≤25K, exceeding this may cause reed deformation and glass breakage.

2. Electromagnetic coil driven type (UQK mechanical level controller)

3. Built-in 4～20mA transmitter circuit board

PCB component temperature rise **≤30K**, maximum chip surface temperature ≤85℃.

IV. Test Judgment Conditions
Rated voltage + full load rated resistive load continuously energized until thermal equilibrium is reached (temperature rise change <1℃ for 30 minutes). Exceeding the limits results in disqualification.

V. Special Limits for Explosion-Proof Products
Explosion-proof ExdⅡBT4: Maximum surface temperature of the entire casing ≤135℃, T6 ≤85℃. Ambient temperature + temperature rise must not exceed the limit.

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