Safety barriers are passive networks for separating intrinsically safe circuits from nonintrinsically safe ones without electrical isolation. Through the use of safety barriers, it ispossible to employ standard instrumentation and installation methods in the nonintrinsicallysafe part of the circuit, provided that there are no voltages higher than 250V present during operation. The safety barriers are designed to meet the requirements othe European Standards EN 50 014 and EN 50 020 developed by CENELEC. Sincesafety barriers contain both intrinsally safe and non-intrinsically safe circuits, they aredesignated “associated equipment” and as such may only be installed in the safe area orin Zone 2. The intrinsically safe circuits in Category “ia” are suitable for Zone 0 and 1areas with a gas explosion hazard, gas groups IIB and IIC, and for Zone 20 and 21 areas with a dust explosion hazard.