Hidden Hazards of PEN Conductor Breakage & REPSUN Smart GSM26 Solution

In the Code for Design of Low Voltage Electrical Installations, the PEN conductor in TN-C systems is subject to extremely stringent control requirements. Electrical codes worldwide explicitly prohibit intentional disconnection of PEN conductor, specify minimum conductor cross-sectional areas, and forbid the installation of separable components such as circuit breakers and fuses on this circuit. These design constraints are intended to eliminate the risk of accidental conductor breakage at the source.

However, industry experience has long demonstrated that that normative restrictions alone cannot fully prevent open-circuit faults in PEN conductors. UK Power Network Document EDS-0017 and BS 7671:2018 both specifically address overvoltage and electric shock hazards arising from PEN conductor breakage. Cable disconnections may be triggered by potential factors including loose and oxidised terminals, cable corrosion, physical damage, and harmonic overloads.

Extending this analysis to the separate neutral (N) conductor in TN-S systems, even when equally rigorous construction and maintenance standards are applied, unexpected disconnection risks remain unavoidable. Such latent faults are difficult to be detected in real time, constituting a major safety blind spot in power distribution and lightning protection engineering.

To tackle the prevalent shortage of grounding conductor monitoring solutions in the lightning & surge protection industry, REPSUN officially launches Smart GSM26, filling the market gap for real-time alarm for PEN and N conductor disconnections in low-voltage installations. With DIN rail mounting, smart GSM26 can be directly installed inside standard distribution cabinets. Through a dedicated N-PE test terminal, the Smart GSM26 continuously and accurately monitors the resistance of the grounding conductor in the power system, thereby enabling real-time monitoring of PEN/N line continuity. Its hardware architecture is fully compatible with three mainstream global grounding systems—TT, TN-S, and TN-C-S—making it suitable for the vast majority of power distribution and lightning protection scenarios, including factories, buildings, photovoltaic systems, and telecom stations. Quick deployment is achievable without large-scale wiring upgrades, delivering superior flexibility and ease of installation versus traditional detectors.

With REPSUN’s proprietary smart monitoring patents, Smart GSM26 conducts 24/7 surveillance of grounding & neutral conductors and records lightning strike events on the grounding system. It evaluates grounding conditions by resistance readings to identify cable ageing, bad contacts and open circuits.

Furthermore, its dedicated module checks N-PE connection integrity and monitors SPD status, avoiding impaired surge protection performance resulting from grounding failure. The Smart GSM26 detects early symptoms of PEN/N line disconnection, providing advance warnings of potential hazards to prevent high voltage intrusion after conductor breakage, which could otherwise damage equipment and endanger personal safety.