ABB AC 31 - 1.5. Different power supply types

Installation
ABB Control - AC 31 Page 4-9
1SBC 260400 R1001-b 06.99
1.5. Different power supply types
The main differences between them concerns the connection of the neutral and the metallic
parts to the earth:
- T-T neutral: The neutral is connected to the earth. All the metallic parts are earthed
(see Figure 4-10).
- I-T neutral: The neutral is isolated in relation to the earth and the metallic parts are
earthed (see Figure 4-11).
Each cabinet (including the 24 V version), in a disturbed environment, should be fitted with an
isolated shielded transformer.