DRAFT - 11 December 2014DRAFT - 11 December 2014INM MTL4850_54 Rev4 194.10.4 Safe area – ring-mained power suppliesA “ring main” system can be used to distribute power to these backplanes in a safe area . Thispermits individual backplanes to be taken out of service without affecting supplies to otherbackplanes. Two or more backplanes can be removed, provided they are neighbours, withoutdisrupting the supply to other backplanes. Make the connections as shown in Figure 4.18.NOTEBackplanes can be ring-mained providing the maximum circuit current does not exceed 12A.Wire sizes up to 2.5mm2 (12AWG) can be used and should be chosen according to load andvoltage drop.Figure 4.18Supply circuitfor interconnectingbackplanes