3. Low-Voltage Power System Basics · Page 1 of 6
What Counts as Low Voltage?
LV definitions and where power-line SPDs typically apply.
Typical LV range
In IEC practice, low voltage generally covers up to 1000 V AC / 1500 V DC. Building distribution at 230/400 V AC is the most common SPD application.
Where SPDs sit
Power-line SPDs are installed at main distribution boards (MDB), sub-distribution boards (SDB), and near critical loads—always with correct backup protection and short leads.
DC systems
PV strings, battery energy storage, and DC busways need DC-rated SPDs. Do not apply AC-only devices on DC circuits.