Learning path

Knowledge Hub

From lightning concepts to low-voltage power-line SPD products—a structured guide for engineers, panel builders, and local partners.

2. Surge Phenomena & Overvoltages · Page 4 of 6

Common-Mode vs Differential-Mode Surges

Know which path the surge takes so you choose the right SPD configuration.

Common-Mode vs Differential-Mode Surges — SPD product family in distributor showroom display shelf

Differential mode (L-N)

Voltage appears between live conductors. Sensitive electronics often fail first in this mode.

Common mode (L-PE / N-PE)

Voltage appears between conductors and earth. Insulation to chassis and communication ports is stressed.

SPD configurations

1P+N, 3P, and 3P+N assemblies provide different combinations of L-N and L/N-PE protection paths. Match the configuration to the supply system (TN-S, TN-C-S, TT, IT).

Need help selecting an LV power-line SPD?

Talk to Protec Power about Type 1 / Type 2 staging, product selection, or becoming a local stocking agent in Southeast Asia and the Middle East.

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