How to Choose a Connector?

A significant portion of machine failures in industry are caused by incorrect connector selection. An unsuitable or low-quality connector leads to unplanned downtime, occupational safety risks and high costs. This guide discusses the technical criteria and considerations for correct selection.

1. Types of Industrial Connectors

Heavy-Duty Connectors

Heavy-duty connectors are designed to safely provide signal, power, data and pneumatic transmission in the harshest industrial conditions. Offering superior resistance to water, lubricants, coolants, dirt and high mechanical stress, these products are preferred in machinery manufacturing, automation lines and heavy industrial applications.

Key Features

• Flexible configuration with modular contact spacers
• UL, CSA, CE international product approvals
• Power, signal and data transfer in a single port
• Sealing up to IP68 degree of protection

CEE Norm Plug and Socket

Industrial plugs and sockets manufactured in accordance with IEC 60309 (CEE 17) are widely used in factories, workshops, construction sites and industrial plants. They are designed to safely carry much higher voltage and current values compared to standard household products.

Technical Specifications

• Rated current 16 A - 32 A - 63 A - 125 A
• Voltage 110 V, 220 V, 380 V, 415 V
• Protection class: IP44 - IP67
• Voltage and ampere identification with color coded system
• Polyamide housing, brass conductive contact

Multi-contact and Combined Systems

Multi-contact plug and socket systems are used for applications where standard solutions are insufficient. With 4, 5, 6, 10, 16 and 24 contact options, they offer solutions for small workshops to large industrial plants. Combined systems provide power and control signals from a single connection point, providing advantages in terms of cable layout and ease of maintenance.

2. Connector Selection Criteria

2.1 IP Protection Class

The IP (Ingress Protection) code defines the level of resistance of a connector against solid objects and liquids according to the IEC 60529 standard. It is the most critical technical criterion for industrial product selection. The first digit in the code stands for dust protection, the second digit for liquid resistance.

IP Class	Dust Protection	Water Protection	Typical Application
IP44	Partial protection	Splash water resistant	Closed workshops
IP55	Dust resistant	Water jet from all directions	Production lines
IP65	Fully dustproof	Low pressure water jet	Outdoor equipment
IP67	Fully dustproof	Temporary underwater (1 m / 30 min)	Food and chemical plants
IP68	Fully dustproof	Permanently underwater	Maritime, mining
IP69K	Fully dustproof	High pressure + hot water	Food/beverage, agricultural machinery

Questions to answer when determining the IP class:

• Will the connector be used indoors or outdoors?
• Is there dust, dirt or metallic particles in the environment?
• Is there water contact, condensation or washing?
• Is there a possibility of exposure to chemicals or lubricants?

2.2 Current and Voltage Values

The current and voltage ratings that the connector must carry are the primary engineering criteria for selection. A connector below the rated value can cause overheating, arcing and short circuit.

• Yük akımı hesaplanırken %20–30 güvenlik payı bırakılmalıdır
• Continuous load and instantaneous peak load should be evaluated separately
• Three-phase (380 V) and single-phase (220 V) systems require different pin configuration
• The frequency value (50 Hz / 60 Hz) must match the product labeling

2.3 Environment Conditions

The operating environment directly affects the IP rating, housing material and mounting type. Chemical plants, food production lines and outdoor applications may have requirements beyond standard IP65 protection.

• In case of chemical contact, body material resistant to acids and bases should be preferred
• IP69K (high pressure hot water washdown) may be mandatory in the food and pharmaceutical sector
• If vibration and impact are present, heavy-duty connectors with locking mechanisms should be selected
• ATEX certified Ex-proof products should be used in flammable and explosive environments
• The operating temperature range must be compared with the product technical values

3. Common Mistakes

Use of Non-Standard Products

The use of household plugs and sockets in industrial environments is one of the most common and costly mistakes. These products deform in a short time in the face of moisture, dust, impact and high current loads, leading to unplanned downtime.

Reflection of the non-standard connector in the production process:

• Unplanned machine downtime and loss of production
• Risk of arcing and short circuit
• Increased preventive maintenance cost
• Occupational safety obligations and possible audit findings

Wrong IP Class Selection

It is a common misconception in practice that the IP protection rating is only waterproof. The IP code covers both solid body and liquid resistance; both aspects must be considered.

• Using IP20 or IP44 rated product outdoors
• Considering IP44 sufficient in humid environment
• IP65 for lines requiring flushing - IP67 or IP69K may be required
• Prefer standard connector in explosive environment

Current and Voltage Mismatch

Connectors that operate continuously at or above the nominal value limit cause overheating and contact erosion. A connector specified without load calculation will either be oversized and create unnecessary cost, or under capacity and produce premature failure.

Ignoring Ambient Conditions

Selection based on current and IP rating alone is not sufficient. Chemical compatibility, operating temperature, mechanical vibration and maintenance period should also be included in the selection process.