6 tips for choosing a power (industrial) connector

6 min

At industrial facilities and construction sites, it is impossible to use conventional sockets – the connected devices are too powerful. To ensure the safety and stability of the operation of all equipment, the connection is made through the power connectors. They differ in the material of manufacture, the number of contacts, the degree of protection against moisture and dust, the maximum current and voltage. First of all, safety depends on the correct choice of an industrial connector, therefore let’s study the main differences between some products from others.

Where might you need a power connector?

A power connector is required wherever high power equipment is used. It can be used both indoors and outdoors. Here are the most common uses for an industrial connector:

  • at the construction site for connecting power tools, concrete mixers, welding machines and other equipment;
  • in production where specific tools are constantly working, incl. pumping, compressor and processing equipment;
  • in kiosks and cabins where, for example, powerful heating devices work;
  • in everyday life, when it is necessary to work with powerful construction tools, turn on the heaters;
  • at sports facilities and camp sites;
  • in agriculture.

This is not a complete list of all possible areas of operation of power connectors. This is such a critical equipment that few companies are engaged in its production, but they offer truly high-quality products. However, low-grade fakes are also found, therefore we recommend buying power connectors in large trusted stores or contacting the manufacturer or its dealers directly.

Body material

Since the requirements for industrial connectors are increased, they must be made of high quality materials. To create a corpus, use:

  • polyamide or polyvinyl chloride is an excellent choice for indoor use. Such connectors are resistant to fires, tend to damp out, therefore they can be used even in fire-hazardous premises. They withstand shock loads well, are sufficiently strong and durable. The polyamide housing is resistant to the ingress of gasoline, salts and a number of other aggressive chemicals. The weak point is the fear of negative temperatures, under the influence of which the material begins to literally split and crumble;

  • rubber does not crack in the cold, tolerates shock and falls well, is not afraid of moisture and dust, is an excellent dielectric, therefore it is better suited for outdoor use. Connectors in a rubber housing are more expensive than those made of PVC.

Now we look inside. Internal conductive parts are made of corrosion-resistant metals. Brass is ideal, copper and bronze are also used. To increase the level of protection against corrosion, metal elements can be additionally coated with a nickel sputtering.

Industrial connector type

Depending on the degree of mobility, power connectors are:

  • portable elements are mounted on the cable, can be completed with auxiliary elements for fixation and protection. They are used where it is necessary to arrange temporary meals for equipment, for example, at a construction site or in a change house;

  • stationary connectors are used in industrial conditions, as well as in everyday life. Can be installed on a base or even on a car. Hidden and open mounting types are used:

    • open type of installation provides for the installation of a surface box on the base. This option is used outdoors, in wooden buildings;

    • the hidden type of installation involves installing the connector in a niche, and the wires are placed in the groove. It turns out neat and functional. Ideal for private homes.

Voltage and current

Power connectors differ in current and voltage. In order for the product to serve for a long time and be safe, it is necessary to choose the most suitable value.

As for the current strength, that is, connectors designed for 16, 32, 40, 63 and 125 A. In everyday life, you can use 16 A, but in production and on a construction site, a higher current value will be required. If the maximum current is greater than the rated current of the connector, the contacts may overheat, and there it is not far from the fire.

The voltage is also different, it can be 220-250 V for a single-phase network and 380 V for a three-phase one. Outwardly, it is not difficult to distinguish such connectors. A single-phase product has one contact for phase, zero and ground, three-phase – three contacts for each of the phases, zero and sometimes ground. It turns out that single-phase connectors have three contacts, three-phase connectors have four or five contacts. We will return to the number of contacts later.

To exclude the occurrence of dangerous situations and the connection of connectors designed for different voltages, currents and frequencies, the IEC 60309 standard was adopted, according to which the devices are color-coded, and the contacts in them are located so that it will be impossible to connect unsuitable parts.

Even a watch of incompatibility has been developed. The connector rail is always located at 6 o’clock, and the location of the ground socket relative to the rail is different for different voltages and frequencies. The size of the power connectors depends on the current, and the ground contact is always larger than others.

To make it easier to distinguish products by frequency and voltage, color coding is used: purple corresponds to a voltage of 20-25 V, white – 40-50 V, yellow – 100-130 V, blue – 200-250 V, red – 380-480 V, black – 500-690 V.

Number of contacts

Depending on the number of contacts, power connectors are:

  • three-pin – widespread, we have already mentioned above. They have three contacts: phase, zero and ground. Such products are used in everyday life and offices.

  • four-contact have three phases and zero, are used when working with equipment with double insulation;

  • the five-pin connector receives three phases, neutral and ground. Required when working with equipment with additional grounding and reinforced insulation.

There is also a non-standard 7-pin connector, 6 of which are located in a circle and one in the center. Used when starting three-phase motors.

Separately, it is worth noting the multi-pin connectors, which serve more to connect multiple equipment and quickly transfer the signal between them, but multi-pin connectors also provide power supply. The scope of their use is wide. They are necessary in the control of air valves, in the operation of signaling installations, for connecting telephone lines, and even for connecting numerous light and sound equipment in halls. There are connectors for 7, 19, 25 and even 150 pins. Just imagine how much equipment can be connected into one system.

And despite the fact that multi-pin connectors have a slightly different scope of use, when choosing them, they look at all the same indicators – current, maximum voltage, degree of protection, material of manufacture, etc.

Multi-pin connectors from Contactica

Contactica supplies multi-pin connectors MARECHAL directly from the manufacturer, therefore you can be sure of quality, as well as the best price. Connectors for 7-37 contacts are presented, with different rated current (from 10 to 50 A), degree of protection, in a plastic and steel case. The company’s managers will help with the selection and, if necessary, will order the required equipment, if it is not available.

Protection level

Since power connectors are rarely used in ideal conditions, it is better to take products with protection from dust and moisture. The level of protection can be judged by the numbers following the letters IP. The first number indicates the level of protection against dust and sand, the second – against moisture. The following types of power connectors are most often found on sale:

  • IP 44 – withstand the ingress of sand and dirt, as well as splashing water;

  • IP 67 – full protection against dust and dirt, resistance to short immersion under water up to 1 m deep;

  • IP 68 – withstand prolonged immersion under water.

If the connector will always work in a dry and warm private house, then there is no point in overpaying for protection.

Finally, we note that if you have difficulties when choosing a power connector, it is better to ask a specialist for help – you will save time, effort, money and you will definitely acquire suitable and safe equipment.

The article was written for the remstroiblog.ru site.

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Passionate about DIY for over 10 years and all the new tools, I give you through this blog all my advice, tips, tests in all areas: carpentry, electricity, masonry, gardening, home automation ...


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