Explosion-proof junction box increased safety "e" flameproof "d" difference

Increased safety "e" explosion-proof electrical equipment GB3836.3-2000 standard requirements

First, the specific technical requirements

Increased safety explosion-proof GB3836.3-2010 standard, but also should meet the content in GB3836.1-2010

1. Solid Insulation Material Requirements

The so-called solid refers to the state of the material in use, and does not mean the initial state of the material. If the insulating paint is solid after solidification, it is also called a solid insulating material. Solid insulation material shall ensure the strength and rigidity of the material when it is higher than the operating temperature of the electrical equipment by 20K (at least 80°C).

2. Clearance and creepage distance requirements

According to the material's comparative tracking index, the new standard divides the materials into three categories I, II, and IIa, which are different from the classification in the old standard (the old standards are divided into four categories: a, b, c, d).

Its value accords with the stipulation of Table 1 in GB3836.3-2010. In the new standard, two grades of 15 to 30 and 15V are added to facilitate the design of low-voltage electrical appliances. For the connection of external wires, the clearance and creepage distance is 3mm.

3 limit temperature requirements

Extreme temperature mainly considers the following two factors:

1) The temperature level specified by the electrical equipment;

2) The thermal rating of the insulation material used. In unfavorable circumstances, such as when the motor stalls, it should ensure that there is a margin for temperature rise.

Second, explosion-proof lighting requirements

1. Distance between light bulb (pipe) and transparent parts

The new standard stipulates that when the power is not more than 60W, the distance between the light bulb and the transparent part is not less than 3mm, and the others are the same as the old standard. Fluorescent tubes have increased heating test and require that the lamps and ballasts are not allowed to exceed the limit temperature after being subject to rectification effects after lamp aging.

2. Allow light source

In this article, the new standard stipulates that other types of lamps whose temperature is not higher than the limit temperature can be used within 10 seconds of lamp rupture. The old standard does not require the lamp to break 10S. Of course, both standards do not allow the use of lamps containing free sodium metal.

3. Energized junction box and junction box

The surface temperature rise of the component caused by the heat loss caused by the contact resistance of the terminal block should be evaluated. Through the wiring terminals with a large cross-section of the wire in series, pass 1.1 times the rated current for assessment

Explosion-proof "d" explosion-proof electrical appliances GB3836.2-2010 standard requirements

Flameproof “d” national standard (GB) GB3836.2-2010 This standard specifies the structural requirements, inspections, and tests for explosion-proof electrical equipment for explosive gas atmospheres. This standard applies to flameproof enclosures made of metal materials and non-metallic materials and their housing components.

The regulations are as follows:

First, the specific technical requirements

This standard applies explosive gas ambient temperature is -20 ~ +60 °C, equipment operating environment temperature is -20 ~ +40 °C. When the equipment operating temperature exceeds -20 ~ +40 °C, according to the provisions of Article 2.3 of the first chapter of this handout. At temperatures below -20°C, the material will become brittle; at temperatures above +60°C, large test safety intervals will decrease.

Second, the thread joint requirements

The number of small engagements of the thread is reduced to 5 buckles. For the length of the small engagement, see 5.3 of GB3836.2-2010. Limits on the prevention of loosening and threading of threaded flameproof joints, and the addition of provisions for special threads

Third, transparent parts requirements

1. The transparent parts can be installed in the form of adhesive and explosion-proof gaskets. Transparencies should be structurally capable of withstanding impact and explosion tests, as well as cushions that act as buffers.

2. The material of the transparent part can be tempered glass, or it can be a plastic whose strength meets the requirements.

Fourth, fasteners requirements

1) The process hole or screw hole that must be pierced is permanently blocked by bolts (such as welding, riveting, etc.);

2) The thread of the screw hole should have a margin, and there will be a certain degree when the fastening bolt is fully screwed in.

3) Generally, there must be measures to prevent loosening;

4) The screw hole must not penetrate the flameproof enclosure. The wall thickness around the screw hole and at the bottom must not be less than 1/3 of the hole, at least 3mm.

Fifth, non-threaded joint requirements

1. For Type IIC flameproof electrical equipment, in addition to the requirements of the old standard for flameproof joints and the requirements for operating rods, the use of planar joints is permitted, but the requirement is: the volume is less than 500cm3, and L≥ For 9.5mm, ic ≤ 0.040mm, flat joint surfaces are allowed, but care should be taken to prevent discharge through the joint surface due to internal dirt or dust deposition, especially incomplete combustion of acetylene, such as gaskets. , baffles, curved roads, etc.

2. The new standard cancels cylindrical joints, defines cylindrical metal parts, and specifies that the joints may have a taper, but the gap should be uniform and in accordance with Tables 1 to 4 of GB3836.2-2010, for Class IIC. When the flameproof joint of the flameproof product has a taper, the taper should be less than 5°.

Six, shell strength design requirements

The strength of the shell should be able to withstand the dynamic pressure test and static pressure test. The number of test gases and tests in the dynamic pressure test is changed. See GB3736.2-2000 for details. The static pressure test can be used as a factory test, and the test time is changed. From the old standard, 1 minute is changed to 102+0 seconds in the new standard.