A floor-mounted electrical transformer is installed on a concrete floor slab with spring or neoprene vibration isolators to prevent solid metallic contact with the supporting structure. A primary service conduit feeds the unit using a length of flexible metal conduit measuring between eighteen and thirty-six inches. The secondary side connects to a utility panel or disconnect via flexible metal conduit with a bushing and ground connector, accompanied by an external number eight American Wire Gauge ground wire. An insulated equipment ground wire runs from the transformer equipment ground stud, connected using a single bolt compression grounding lug, and ties into the building steel with an exothermic weld connection.
PRIMARY SERVICE CONDUIT FLEXIBLE METALIC CONDUIT MINIMUM 18" TO MAXIMUM 36" GROUND CONNECTOR BUSHING WITH GROUND WIRE FLEXIBLE METAL CONDUIT MINIMUM 18" TO MAXIMUM 36"-PROVIDE CONDUIT DROP FROM PANEL WITH CONNECTOR FOR CONVERSION TO FLEXIBLE. 1#8 AWG EXTERNAL SEE NOTE 2 NAMEPLATE TO BUILDING STEEL WITH EXOTHERMIC WELD CONNECTION TRANSFORMER FLOOR SLAB SPRING ISOLATOR TYPE VIBRATION ISOLATION (SEE NOTE 4 & 6) SECONDARY DISCONNECT OR UTILITY PANEL NOTES: 1. PROVIDE A MINIMUM OF 8" TO ALL WALLS AND EQUIPMENT FOR VENTILATION. (12" FOR 75KVA AND GREATER.) 2. INSULATED EQUIPMENT GROUND WIRE TO BUILDING STEEL. GROUND TO TRANSFORMER X/O EQUIPMENT GROUND STUD. CONNECT WITH SINGLE BOLT COMPRESSION GROUNDING LUG. 3. CONTRACTOR SHALL ENSURE ADEQUATE CLEARANCE FOR MAINTENANCE/INSPECTION. 4. THERE SHALL BE NO SOLID METALLIC CONTACT BETWEEN TRANSFORMER AND SUPPORTING STRUCTURE. 5. EXACT MOUNTING LOCATION OF TRANSFORMER SHALL BE APPROVED BY LANDLORD IN FIELD PRIOR TO INSTALL. EC SHALL V.I.F. THAT INSTALLATION DOES NOT FRINGE ON ANY EXISTING EQUIPMENT/PANEL(S) CLEARANCE AREAS. 6. SPRING ISOLATORS TO BE SIMILAR TO MASON TYPE SLF SIZED FOR A MINIMUM STATIC DEFLECTION OF 1" ABOVE 75KVA. PROVIDE NEOPRENE ISOLATORS SUCH AS MASON TYPE SUPER W FOR 75KVA AND BELOW OR AS OTHERWISE DIRECTED BY ACOUSTICAL CONSULTANT.
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