Is it necessary to add a safety barrier to an intrinsically safe locator?
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Could that expert advise whether a safety barrier is necessarily required externally for an intrinsically safe locator with a 4-20mA signal input? Can the locator function properly without a safety barrier?
It can work normally without it. The explosion-proof area uses intrinsically safe cables along with safety barriers
Intrinsic safety instruments, also known as safe-spark instruments, are devices in which, whether under normal operating conditions or in the event of a fault, the sparks generated by the circuits and systems, as well as the temperatures reached, will not cause an explosion of explosive mixtures. The explosion protection of intrinsically safe instruments is primarily achieved through the following measures: ① Using new types of integrated circuit components to construct the instrument circuit, allowing it to operate at lower operating voltages and lower operating currents ； ②Use safety barriers to separate the circuits in hazardous areas from those in non-hazardous areas, thereby limiting the energy that can be transmitted from non-hazardous areas to hazardous areas ； ③The connection wires of the instruments should not create excessive distributed inductance and distributed capacitance, in order to reduce the energy stored in the circuit. It can be used in all hazardous locations and with all explosive gas and vapor mixtures, and can be maintained and adjusted while powered on. However, it cannot be used alone; it must form an intrinsically safe circuit together with intrinsically safe associated devices (safety barriers) and external wiring in order to exert its explosion-proof function.
Omitting the safety barrier does not affect the basic functions of the locator, but it fails to meet the explosion-proof requirements.
I have a question: do all three measures need to be met, or is it sufficient to meet just one of them?
Intrinsic safety instruments, connection wires to the safety barrier – all three are necessary as part of a safety system
Intrinsic safety: the entire instrument circuit must be intrinsically safe, including intrinsic safety barriers and intrinsic safety cables; otherwise, it’s useless even if the instrument itself is intrinsically safe. Intrinsic safety refers to the entire circuit.
If we only talk about operation, ignoring explosion protection and safety barriers, it is still possible to operate; just make sure about power distribution. If it is an explosion-proof area, a safety barrier is still necessary; otherwise, it will not provide explosion protection, and things will go wrong in case of an explosion. .