3. Low-Voltage Power System Basics · Page 4 of 6
Neutral and Protective Earth Roles
Why N and PE mistakes create both shock and surge problems.
Keep functions clear
Neutral carries load current. PE is for safety and fault current. Mixing them casually defeats both shock protection and surge equipotential design.
SPD earth connection
The PE terminal of an SPD must reach the main earthing bar via a short, straight conductor. Long coiled earth leads add inductive voltage that appears across equipment.
MEN / bonding links
At the service position, bonding rules are defined by local wiring codes. SPD design must follow those rules, not invent a parallel earthing philosophy.