Handling and Connection of Cables and Lines for Fixed Laying - Course: Basic skills and knowledge of electrical engineering. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 17 p.): 3. Connection of Cables and Lines for Fixed Laying to Electrical Equipment: 3.2. Criteria for Clamped Joints in Electrical Installations

Handling and Connection of Cables and Lines for Fixed Laying - Course: Basic skills and knowledge of electrical engineering. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 17 p.)

3. Connection of Cables and Lines for Fixed Laying to Electrical Equipment

		(introduction...)
		3.1. Making Screw Joints
		3.2. Criteria for Clamped Joints in Electrical Installations
		3.3. Pressed Joints
		3.4. Making Wire-wrap Joints
		3.5. Making Soldered Joints

3.2. Criteria for Clamped Joints in Electrical Installations

- For clamped connections of lamps it is important that the neutral conductor is always connected to the ring contact and the switch-lamp-wire always to the floor contact.
- Disconnection through switches is allowed for phase conductors only.
- Switches are to connected so that the so-called TRR rule is observed, i.e. the circuit is closed when the switch is in

· top position
· rear position
· right-hand position.

- For connection of switches, attention is to be paid to switch connection marks. (Always connect phase conductors to the terminals marked accordingly.)
- For connection of sockets, the phase conductors are to be clamped at the left-hand side and the neutral conductor with protective conductor function (PEN) or the neutral conductor and protective conductor at the right-hand side.
- The phase conductor sequence (e.g. in the order black, blue, brown) is to be observed when connecting power sockets and other installation units.

Figure 18 Connecting of a power socket

1 conductor 1, 2 conductor 2, 3 conductor 3, 4 PEN, phase conductor sequence, for example, black, blue, brown, green/yellow starting with conductor 1

Non-observance of the correct phase sequence within an installation will result in malfunctions, such as wrong direction of rotation of motors etc.

- In branch or conduit boxes, the phase conductors are to be connected on the left-hand top and the neutral conductor or neutral conductor with protective function on the right-hand bottom.
- If branch or conduit boxes have a fifth connection terminal, the protective conductor only is to be connected to that terminal.

Figure 19 Examples for terminal connections in branch boxes

What are the advantages of a consistent system of clamped connections in electrical installations?
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