# Power supply to mains switch box

TN or TT mains are to be preferred

If the power supply system isn’t as shown above an isolation transformer is needed. Below are shown some examples of additional power supply system types using up to 480 VAC (phase to phase) where an isolation transformer is required

Examples

Legend |
--- | ---
A | Factory power supply system
B | Transformer
C | Mains switch box

Examples 1:

Examples 2:

Examples 3:

Examples 4:

Examples 5: