ABB Arc Guard System — Fibre-Optic Arc Flash Detection

The ABB Arc Guard system with TVOC-2 central unit and fibre-optic sensing loops provides the fastest available arc flash detection for LV and MV switchgear — detecting the intense light flash of an arc fault within less than 1 millisecond and issuing a direct hardware trip command to the circuit breaker before the arc fault current builds to its prospective level. Compared to conventional overcurrent relays that require the full arc fault current to flow for 50–200 ms before tripping, the Arc Guard's optical sensing mechanism responds to the arc flash's light output before the overcurrent relay has even registered the fault — reducing the incident energy absorbed by the arc fault and the surrounding electrical equipment by a factor of ten or more. This dramatic reduction in incident energy is the fundamental goal of arc flash safety: an incident energy below 8 cal/cm² avoids second-degree burns to workers wearing PPE rated to NFPA 70E Category 2, while incident energies above 40 cal/cm² represent life-threatening injuries regardless of PPE.

The TVOC-2-FO arc flash detection unit monitors up to six independent fibre-optic sensor loops, each covering a distinct zone within the switchgear — incoming compartment, busbar compartment, and outgoing compartments — providing zone-selective arc detection that identifies which specific compartment the arc fault is in, enabling selective tripping of only the circuit breaker feeding that compartment rather than the entire switchboard. Optional current-sensing input combines with optical detection to provide validated arc detection — requiring both optical signal above threshold AND current above minimum fault level — preventing nuisance trips from non-fault light sources such as torch light or camera flashes during inspection. The direct hardware trip output connects to the circuit breaker's shunt trip coil via a dedicated relay contact, bypassing the normal protection relay trip circuit to achieve the fastest possible breaker opening time.

In Saudi Arabia's electrical safety regulatory environment, arc flash protection is increasingly required by ARAMCO engineering procedures (SAES-P-100 references NFPA 70E arc flash hazard analysis), SABIC safety management systems, and the SASO equivalent of IEC 62271-200 for new switchgear. The majority of Saudi Arabia's serious electrical accidents occur during switchgear operation and maintenance activities — the exact conditions where arc flash protection is most critical. NFPA 70E arc flash hazard analysis mandatory for ARAMCO and SABIC electrical contractors produces working distance and incident energy calculations that in many cases require arc flash protection systems to reduce calculated incident energy to a level manageable with available PPE. ABB Arc Guard is accepted as a mitigating measure in ARAMCO and SABIC arc flash hazard analyses, directly reducing the calculated incident energy at the working distance and enabling safer electrical work.

Razz Middle East supplies and installs ABB Arc Guard systems for new switchgear and as retrofit installations in existing switchgear. Our arc flash engineers perform arc flash hazard analysis calculations to NFPA 70E and IEEE 1584 methodologies, specify the Arc Guard system configuration, and provide commissioning and testing documentation required for ARAMCO and SABIC electrical safety file submissions.