To avoid hazardous situations, all intrinsically secure machinery, so that unnecessary heat or fire sparks are not generated by electrical overloads.
A system consisting of equipment and interconnecting equipment in which any spark or heat impact is unable to cause a fire in any portion of the device designed for use in dangerous fields and isolate it from outside area to avoid the fire to spread.
By using obstacles in the loop and using IS wires, the cause of ignition is regulated. The only methods considering flaws in the linking wires are intrinsic security.
Working of an Intrinsic circuit:
A fault force obtained from the stage voltage of the mains invades the barrier’s safe-area part. Part of the current may flow through the barrier fuse, rupturing it; but a significant part of it would flow through the barrier system’s 0 V rail, being limited in magnitude only by the impedance of the fault circuit, and its duration determined by the fuse or other fault-current limitation that protects the fault-current phase.
The transfer route to the neutral star stage guarantees that the fault current does not reach the dangerous region by displaying a lower impedance route that the present wants to pass along.
A voltage decrease happens in the transfer route between the X1 and X nodes during the fault present flow. This change in voltage is transmitted to the ground attached tool as the box is attached to the system with the same capacity as point X and the inner components immediately linked to point X1.
Since this voltage distinction happens in the dangerous region, it is natural that it should be less than 10 V so that an incendiary spark’s likelihood is acceptably small.
The multiple return paths and cross bonding must create a low resistance return path of the same order as the barrier earth conductor so as to avoid significant voltage differences.
Using Galvanic isolator:
The use of galvanic isolators as interfaces changes the earthing requirements from being a primary contributor to the method of protection, to a secondary one.
The fault is cleared in a comparatively brief period of moment by getting a well-defined return track on the isolator’s safe hand.
The voltage concentration of the isolator’s safe-area side is not transmitted to the dangerous zone, but a lengthy hand failure would harm the parts on the safe-area side or more likely harm the input circuit.