Cables > CAT5e

The environment determines whether cable should be shielded or unshielded.

Shielding is the sheath surrounding and protecting the cable wires from electromagnetic leakage and interference. Sources of this electromagnetic activity (EMI)—commonly referred to as noise—include elevator motors, fluorescent lights, generators, air conditioners, and photocopiers. To protect data in areas with high EMI, choose a shielded cable.

Foil is the most basic cable shield, but a copper-braid shield provides more protection. Shielding also protects cables from rodent damage. Use a foil-shielded cable in busy office or retail environments. For industrial environments, you might want to choose a copper-braid shield.

For quiet office environments, choose unshielded cable.

Ethernet technology is coming to the factory floor. Once limited to networks in office environments, Ethernet has also proven to be a robust alternative to the RS-232 interfaces traditionally used with industrial devices such as programmable logic controllers. Ethernet brings speed, versatility, and cost savings to industrial environments.

The requirements of industrial environments are different from that of offices, so there’s been a proliferation of industrial Ethernet standards. The most commonly accepted is the Ethernet/Industrial Protocol (Ethernet/IP) standard, usually called Industrial Ethernet. Industrial Ethernet adapts ordinary, off-the-shelf IEEE 802.3 Ethernet communication chips and physical media to industrial applications.

The Ingress Protection (IP) ratings developed by the European Committee for Electrotechnical Standardization (CENELEC) specify the environmental protection an enclosure provides.

An IP rating consists of two or three numbers. The first number refers to protection from solid objects or materials; the second number refers to protection from liquids; and the third number, commonly omitted from the rating, refers to protection against mechanical impacts.

Because office-grade RJ-45 connectors do not stand up to an industrial environment, the Ethernet/IP standard calls for sealed industrial RJ-45 connectors that meet an IP67 standard, meaning the connectors are sealed against dust and water.

First IP Number

0 No protection

1 Protection from solid foreign objects of 50 millimeters or greater

2 Protection from solid objects (up to 12 millimeters)

3 Protection from solid objects more than 2.5 millimeters

4 Protection from solid objects more than 1 millimeter

5 Protected from dust, limited ingress

6 Totally protected from dust, dust tight

Second IP Number

0 No protection

1 Protection from vertically falling drops of water and condensation

2 Protection from direct sprays of water up to 15° from the vertical

3 Protection from direct sprays of water up to 60°from the vertical

4 Protection from splashing water from all directions

5 Protection from low-pressure water jets from all directions

6 Protection from high-pressure water jets

7 Protection from temporary immersion up to 1 meter

8 Protection from long periods of immersion under pressure

Third IP Number

0 No protection

1 Protection from impact of 0.225 joule (150 grams falling from 15 cm)

2 Protection from impact of 0.375 joule (250 grams falling from 15 cm)

3 Protection from impact of 0.5 joule (250 grams falling from 20 cm)

4 Protection from impact of 2.0 joule (500 grams falling from 40 cm)

5 Protection from impact of 6.0 joule (1.5 kilograms falling from 40 cm)

6 Protection from impact of 20 joule (5 kilograms falling from 40 cm)