There are two national standards for electric tubular heating element industry, one is GB2379-93, which is the standard for industrial electric heating pipe, and the other is 4088-99, which is the standard for domestic heating elements.
According to the relevant national standards, the electric tubular heating element has the following requirements:
1. When the temperature rise time is under the test voltage, the time for the element to rise from the ambient temperature to the test temperature shall not be more than 15min
2. Rated power deviation
2.1 under the condition of sufficient heating, the deviation of rated power of components shall not exceed the range specified below;
2.2 for components with rated power less than or equal to 100W: ± 10%.
2.3 for components with rated power greater than 100W: 5% ～ - 10% or 10W, whichever is greater.
3. Leakage current
3.1 the cold leakage current, leakage current after water pressure and sealing test shall not exceed 0.5mA
3.2 the hot leakage current under the working temperature shall not exceed the calculated value in the formula, but the larger value shall not exceed 5mA
I=1/6（tT×0.00001）
I-hot leakage current Ma
T - heating length mm
T - working temperature ℃
When multiple elements of the electric heating tube are connected in series to the power supply, the leakage current test shall be carried out with this group of elements as a whole.
4. Insulation resistance
Cold insulation resistance shall not be less than 50m Ω during delivery inspection
After sealing test, the insulation resistance after long-term storage or use shall not be less than m Ω
The thermal insulation resistance under the working temperature shall not be lower than the calculated value in the formula, but the smaller insulation resistance shall not be less than 1m Ω
R=「（10-0.015T）/t」×0.001
R - insulation resistance in hot state m Ω
T - heating length mm
T - working temperature ℃
5. Insulation withstand voltage strength
The element shall be kept for 1min under the specified test conditions and test voltage without flashover and breakdown.
6. Ability to withstand power on and power off
The components shall be able to undergo 2000 on-off tests under the specified test conditions without damage.
7. Overload capacity
The components shall withstand 30 cycles of overload test without damage under the specified test conditions and input power.
8. heat resistance
Under the specified test conditions and test voltage, the element of electric heating tube shall withstand 1000 cycles of heat resistance test without damage.
