An IP44 industrial socket is consists of the housing, the pins, the terminal seat, the seal, the cable clamp, the grip, and the fixing screws.
As the industrial socket is a manually operated part, it is required to has the following characteristics: standard size, reliable and easy wiring, ergonomic design for hand grip, and reasonable structure.
The following text explains each part of the IP44 industrial socket.
- Housing
The housing part is a one-piece designed plastic casing that contains and protects the inner parts. The outer shape is designed with an ergonomic mind.
The size of the diameter, the positioning key, and the holding block must comply with the GB/T 11919-2001 standard.
The surface is always designed with an uneven pattern to increase force of friction so that it can be firmly held by hand.
Regarding the assembly structure, there are two types for an IP44 industrial socket: one-piece type and two-section type.
For the two-section housing, the front section is designed with housing function and also with terminal seat function. The rear section is the grip. The two sections are connected by a self-tapping screw. The connection type is either slot or teeth. The position and connection can be guaranteed to meet IP44 rating.
At the current time, some of the two-section housing use a fast connection method by not using the fixing screws.
Information such as logo, model, specifications, and certificates are printed on the housing surface.
The housing is usually made of thermoplastic plastic. The material has superb mechanical and electric performance, such as crush resistance, aging resistance, heat and flame resistance, etc. At present, most of the housing for IP44 industrial socket is made from PA or PC material. For some bad environments with high temperatures, special light aluminum alloy material is also used.
- Cover
The cover is used to protect the pins and the slots from dust and water. In addition, it also prevents people from getting an electric shock during operation.
The cover is in flat round shape. The front surface is printed with a logo, model, specifications, etc.
The cover is made of insulating material.
- The terminal seat
The terminal seat is used for fixing all the pins and insulate them.
As the terminal seat is installed inside the socket, while the socket is connected, the current is passing through the pins and the seat, the heat generated by the contact resistance on the surface is accumulated. Therefore, the material of the terminal seat must be heat-resistant, such as glass fiber reinforced nylon.
In order to reduce the product cost, the terminal seat is designed with a thin-wall concept. Some internal parts are hollow out without losing strength.
- The seal
Together with the terminal seat, the seal is protecting the pins from being pushed out with too much force.
- The pins slot
The pin slots are the conductive parts. The pin slot must have the minimum required pullout force as listed in the table below.
| Pin diameter (mm) | 5 | 6 | 7 | 8 | 10 | 12 |
| Minimum pullout force (N) | 2.5 | 5 | 5 | 10 | 15 | 20 |
Table 1: the minimum pullout force for pin slot
To avoid the situation that the pins are difficult to pull out, it is required that the maximum pullout force shall not exceed as stated in the table below.
| Rated current (A) | 16/20 | 32/30 | 63/60 | 125/100 |
| Maximum pullout force (N) | 125 | 150 | 5 | 275 |
Table 2: the maximum pullout force for pin slot
According to the different pole configurations, the pins can be divided into P (phase pin), N (neutral pin), E (earth pin), and support pin.
The pin slots are made from brass. For each pin slot, it contains above 58% of brass so that the conductivity and the mechanical performance can be satisfied.
Normally a nickel coating is added to increase the resistance ability to rust and mechanical damage.
- Spring parts
The spring parts make the pins elastic enough to better contact with their counterparts.
There are two types of spring parts in the pins of the IP44 industrial socket: the ring and the cage spring ring.
- Rivet
The rivet has two functions, one is to fix the cover on the housing, the other one is to act as the axile for the turning of the cover.
There are two kinds of rivets on the industrial socket.
One is the bolt type. For the socket with rated current less than 32A, it uses the rivet with the outer diameter of 4mm. The surface is treated with anti-rust coating.
The other one is the shaft type. The shaft rivet is plastic. It is very easy to mount and remove. It is always used on the sockets with the rated current higher than 63A.