Ring Main Units
All our RMUs are of the ‘load make fault break type’ and are oil insulated with both the fuses and bus bars immersed in oil. The cable boxes for the stand alone units are ‘internal arc tested’ and the units also consist a ‘pressure release vent’ at the back to protect the operator from hot oil should the RMU be switched into a fault.
Hawker Siddeley manufactures and uses the 12kV ‘Tiger’ range of oil filled 630A load break switches, fused automatic switches and combination ring main units for indoor/outdoor use and in Mini-Substations or as stand-alone switchgear with the following alternative arrangements;
NX3F: Double Isolator with Fused Tee-Off
NX3: Three Isolator Unit
X2F: Single Isolator for Left or Right Hand Side with Earthing plus a Fused Tee-Off
X1F: Fused Tee-Off Switch with Earthing Facility
X2: Double Isolator with Ring Earthing & Cable Testing facilities
X1: Single Isolator with Earthing & Cable Testing facilities
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