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HomeMy WebLinkAbout3PH TRANSFORMER FLAT PAD INSTALLATION - 23-00093 - Liberty GMC - ElectricalPolicy 242—Underground Conduit Systems for Primary and Secondary Conductors 7. Equipment Bases—Flat Pads Flat pads, shown in "Figure 59" below, are used to support three-phase transformers that have three or fewer secondary or service conduitsl . The customer may elect to use padvaults in lieu of flat pads. Flat pads may be poured in place or purchased pre -cast by the customer. In both cases, the customer shall follow good construction practices with 18 inches (18") of soil removed, the remaining soil compacted, and the hole filled and compacted with 3/ -inch -minus gravel prior to either pouring the pad or setting the pad. Pads shall be set so they are level with about three inches (3") of the pad left above final grade. See Figure 61 for flat pad specifications. Figure 59—Three-Phase Transformer on a Flat Pad 7.1. Three -Phase Transformer Flat Pads 7.1.1. Concrete Flat Pads The drawings and pictures in this section represent typical installations. The left-hand picture in "Figure 60" below shows a properly installed three-phase transformer cabinet. Flat pads are limited to three-phase transformers with no more than three runs of conduit on the secondary side. . . 'cw merty �CfotFt�it+ i�s�ti rn� the ffx�rplwsemnsfamwonBoat Pad. AvdukshWWb*UWj. 1The number of conduits is based on the preferred number of conduits identified in Power Company standard GS 031, Underground Secondary and Service—Three-Phase Service Cable. Printed versions of this policy maybe outofdate- Pleaseconsulttheweb ROCKY MOUNTAINf pages for the most recent version. This document shall be used and duplic- ROCKI� ated only in support of Rocky Mountain Power projects. POWER 42 ©2019 by PacifiCorp. AMVt$*kof PAU Kour Policy 242—Underground Conduit Systems for Primary and Secondary Conductors Figure 60—Three-Phase Transformer Flat Pad 7.1.2. Dimensions and Installation, Three -Phase Transformers Notes: The customer shall leave 10 feet (10') of #6 AWG copper, fed underneath and through the open area on the right side of the flat pad. This is used for bonding adjacent metallic equipment. Flat pads may be poured on-site or purchased from an approved vendor. For flat pad construction, the Power Company specification ZG 311, Concrete Requirements, must be followed. ZG 311 is available online at rockymountainpower. net, Contractors, Underground Conduit Systems, or from a Power Company contact. ftal Ira" it buns'� 30" I —}---g---I— ---T--i— #4 Rebar I I Froax. f i r —.L _J_ --I I" i � �: r __J.L__L,.__i__�_ j_ i i l l I I I I r$" 12' •• 20" 20" >, 20- 12" 4 oaa 84' high open area low Voltage (no oonaete, voltage area noconcl l) area 6" (root drawn to scale) The customer is responsible for installing the bonding wire; see Section 5.7 (not drawn to scale) 24- T Figure 61—Dimensions and Installation of aThree-Phase Transformer Flat Pad Notes: 1. For flat pad construction, the Power Company's specification, ZG 311, Concrete Require- ments, must be followed. ZG 311 is available online (at rockymountainpower. net, Con- tractors, Underground Conduit Systems) or from a Power Company contact. 2. The customer shall leave 10 feet (10') of#6 AWG copper, fed underneath and through the open area on the right side of the flat pad. This is used for bonding adjacent metallic equip- ment. 3. Flat pads may be poured on-site or purchased from an approved vendor. ROCKYMOUNTAIN Printed versions ofthis policy maybe out of date- Please consult the web pages for themost POWER recent version. This document shall be used and duplicated only in support of Rocky Mountain A 0:...Vh Of #01' s,c o.• Power projects. ©2019 by PacifiCorp. 43 Policy 242—Underground Conduit Systems for Primary and Secondary Conductors 4. The customer is responsible for installing the bonding wire. See Section 5.7. 7.1.3. Excavation, Flat Pad — Three -Phase Transformers Notes: 1. Level a 9'X 9' square and bring conduits up using 900 elbows. 2. Cap the elbows. 3. Follow good construction practices with 18 inches of soil removed, the remaining soil com- pacted, and the hole filled and compacted with %-inch minus gravel. 4. The flat pad is set at three inches above the final grade.