27.00-00ADWG.

27.00-03MARKINGS FOR PAD-MOUNTED TRANSFORMERSSINGLE-PHASE PAD-MOUNTED TRANSFORMER CATALOG NUMBERS 27.00-10

27.00-14SECONDARY SET SCREW CONNECTORS

FUSING GUIDELINES FOR PAD-MOUNTED TRANSFORMERS 27.02-04FUSING GUIDELINES FOR VAULT TRANSFORMERS 27.02-02

UNDERGROUND DISTRIBUTION SPECIFICATIONSUNDERGROUND DISTRIBUTION SPECIFICATIONS 27.00-01

27.00-02

27.00-12PAD-MOUNTED TRANSFORMER WEIGHTS

REPLACEMENT STUDS - 200 AMP BUSHING WELLS 27.00-16

GROUNDING DETAILS FOR SINGLE-PHASE LOW-PROFILE PAD-MOUNTED27.01-03

GROUND DETAILS FOR THREE-PHASE LOOP FEED TRANSFORMERS 27.01-04

OPERATING PROCEDURE FOR INSTALLING ELBOW SURGE ARRESTERS 27.03-02AOPERATING PROCEDURE FOR INSTALLING ELBOW SURGE ARRESTERS 27.03-02B

FEED THROUGH BUSHING INSERT IN LOW PROFILE PAD-MOUNTED TRANSFORMERS 27.05-10

SECTION 27 - PAD-MOUNTED TRANSFORMERS

TABLE OF CONTENTS

TRANSFORMERS

ARRESTER-ELBOW THREE-PHASE DEADFRONT LOOP NON INT-HVLAARRESTER-ELBOW THREE-PHASE DEADFRONT LOOP WITH INT-HVLA

ARRESTER-ELBOW AND FEED-THRU, SINGLE-PHASE PAD-MOUNT WITHOUT ARRESTER - FEED-THRU SINGLE-PHASE PAD-MOUNT WITH INTERNAL ARRESTER

INTERNAL ARRESTER

27.03-12

27.03-1527.03-1427.03-13

OPEN WYE-OPEN DELTA TRANSFORMER BANK 120/240 VOLT, 4-WIRE SERVICE

OPEN WYE-OPEN DELTA TRANSFORMER BANK 120/240 VOLT, 4-WIRE SERVICEUSING SINGLE-PHASE 14.4KV PAD-MOUNTED TRANSFORMERS

USING SINGLE-PHASE 7.2KV AND 7.6KV PAD-MOUNTED TRANSFORMERS

27.05-12

27.05-13

BAY-O-NET FUSE OPERATING INSTRUCTIONSBAY-O-NET FUSE OPERATING INSTRUCTIONS

27.02-0927.02-10

STANDARD SINGLE-PHASE PAD-MOUNTED TRANSFORMERS AND SINGLE-PHASE27.02-05FUSE TABLE

STANDARD THREE-PHASE PAD-MOUNTED TRANSFORMERS AND BAY-O-NET27.02-07FUSE TABLE

REVISED BY CK'D APPR.

O

1

2

10/29/10 CECCONI ELKINSGUINN

3

OPEN WYE-OPEN DELTA TRANSFORMER BANK 480 VOLT, 3-WIRE SERVICE USINGSINGLE-PHASE 7.2KV AND 7.6KV PAD-MOUNTED TRANSFORMERS 27.05-14A

OPERATING PROCEDURE FOR MITIGATION OF FERRORESONANCE 27.03-02C

THREE-PHASE PAD-MOUNTED TRANSFORMER CATALOG NUMBERS 27.00-11

27.00-13MAXIMUM TRANSFORMER LOADING (UG)

THREE-PHASE OPEN WYE-OPEN DELTA CONNECTION 7200/12470 TO 240/480VPAD-MOUNTED TRANSFORMER 480 VOLT THREE-PHASE THREE WIRE SERVICE 27.05-14B

IDLE TRANSFORMERS 27.00-22

7/7/11 DANNA ELKINSBURLISON

EXTENDED BUSHING INSERT IN LOW PROFILE PAD-MOUNTED TRANSFORMERS 27.05-11

10/29/10 CECCONI GUINN ELKINS

27.00-00BDWG.

THREE-PHASE PAD-MOUNTED TRANSFORMERS GENERAL INFORMATION 27.06-02THREE-PHASE PAD-MOUNTED TRANSFORMER (CONT.) GENERAL INFORMATION 27.06-03LOCATION OF OIL FILLED PAD-MOUNTED TRANSFORMERS 27.06-05PROTECTIVE POLES FOR OIL FILLED PAD-MOUNTED TRANSFORMERS 27.06-06THREE-PHASE PAD-MOUNTED TRANSFORMER WITH CUSTOMER'S SECONDARY

27.06-08CABLE TERMINATION BOX INSTALLATION

TRANSFORMER SECONDARY SPADE BLOCK TERMINALS 27.06-12

SECTION 27 - PAD-MOUNTED TRANSFORMERS

TABLE OF CONTENTSREVISED BY CK'D APPR.

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3

RECOMMENDED NUMBER OF CUSTOMER CONDUCTORS IN SECONDARY27.06-09COMPARTMENT OF THREE-PHASE PAD-MOUNTED TRANSFORMERS

THREE-PHASE PAD-MOUNTED TRANSFORMERS PRIMARY AND SECONDARY WINDING -27.06-28NEUTRAL CONNECTIONS LABELS FOR 3 WIRE SERVICES

THREE-PHASE, THREE-WIRE 480 VOLT SERVICE 27.06-16THREE WIRE SERVICES, FLOATING WYE CONNECTION 27.06-18FOUR WIRE SERVICES, GROUNDED WYE CONNECTION 27.06-22THREE-PHASE PAD-MOUNTED TRANSFORMERS PRIMARY AND SECONDARY WINDING -

27.06-26NEUTRAL CONNECTIONS VARIATIONS FOR 3-WIRE SERVICES

THREE-PHASE TRANSFORMER CONNECTION TO SINGLE-PHASE TRANSFORMER 27.06-30

4/13/11 CECCONI BURLISON ELKINS

7/15/11 CECCONI BURLISON ELKINS

MAKE SURE ELBOW IS GROUNDED. WITH

#4 SD BC GROUND LOOP

5/8" COUPLING

5/8" GND. ROD CLAMP

DEEP DRIVEN

GND. WIRE MUST BEINSTALLED ON OPPOSITESIDE FROM SET SCREW

SECTIONAL ROD

DWG.

27.01-0310/28/10

GROUNDING DETAILS FOR SINGLE-PHASE

LOW-PROFILE PAD-MOUNTED TRANSFORMERS

DETAIL "A" DETAIL "B"

CN 160123

5/8" X 5'GND. RODCN 9220192319

CN 160182CN 060136

CN 9220069244

SEE DETAIL "A"

SEE DETAIL "B"

BONDING PADSEE DETAIL "C"

ACCEPTS 1/2" X 13BONDING PAD

PAD

DETAIL "C"

CONNECTOR (PROVIDED

PMT

SILL

H1A

H1B

0

2

1

APPR.REVISED BY CK'D

3

ELKINSSIMMONS GUINN

A PIECE OF THE

BY OTHER UTILITY)

DETAIL "D"

BAIL-TABEYE

GROUNDINGPAD

INSERT

BUSHINGCLAMP

CONCENTRIC NEUTRALWIRE

#4 CONNECTORCN 162204

ENSURE GROUNDLOOP IS BONDEDTO TANK AT THESE

NOTES:

EQUIPMENT GROUNDING AND BONDING.1. SEE DWG. 20.00-06B FOR ADDITIONAL INFORMATION ON

9/28/11 ELKINSSIMMONS BURLISON

METAL

METALLIC BUSHING CLAMP

MAKE SURE BUSHING INSERT IS BONDED TOMETAL. SEE DETAILS"D" AND "E"

DETAIL "E"PLASTIC BUSHING CLAMP

THREE LOCATIONS

BOND INSERT TOMOUNTING STUD WHENBUSHING FLANGE ISPLASTIC

DWG.7/7/11 DANNA BURLISON ELKINS

NOTES:

27.05-11

EXTENDED BUSHING INSERT IN

LOW PROFILE PAD-MOUNTED TRANSFORMERS

2. ALL LOADBREAK ELBOWS SHALL BE PROPERLY CABLE TRAINED AND FREE TO MOVE TO AN INSULATINGBUSHING (CN 326236) MOUNTED ON A PARKING STAND WHILE USING AN INSULATED ELBOW PULLING STICK.

3. SEE DWG. 27.01-03 FOR PROPER GROUNDING DETAILS.

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APPR.REVISED BY CK'D

3

H B1

H A1

SOURCE

LOAD

1. EXTENDED BUSHINGS SHOULD BE USED WHEN SECONDARIES CONTAIN 6 OR MORE RUNS OF 350KCM ORLARGER CABLE.

1 TUA15BUSHINLBEF

BILL OF MATERIALS

CATALOG

152197 BUSHING INSERT, EXTENDED

DESCRIPTION

2

QTY

1

PERCU

NUMBERMACRO UNIT

-

CUITEMNO.

COMPATIBLE UNIT

QTYREQ'D

STANDARD THREE-PHASE, PAD-MOUNTED TRANSFORMERS

THE STANDARD THREE-PHASE PAD-MOUNTED TRANSFORMER IS A DEAD FRONT, LOOP FEED TRANSFORMER.

USING A LOOP FEED UNIT

(CONVERTING LIVE-FRONT TERMINATIONS TO DEAD-FRONT) AS A TEMPORARY "FIX", IT MAY BE MORECONVENIENT TO CUT THE PRIMARY CABLE JUST BELOW THE STRESS CONE AND SPLICE ON A SECTIONOF CABLE AND AN ELBOW IN THE PRIMARY COMPARTMENT OF THE TRANSFORMER. AN OUTAGE SHOULDBE SCHEDULED WITH THE CUSTOMER AT A LATER DATE TO CUT THE PRIMARY CABLE BACK TO A POINTWHERE THE SPLICE(S) MAY BE BURIED. IF CABLES ARE INSTALLED IN CONDUIT(S), THE ENTIRE CABLERUN SHOULD BE REPLACED IF POSSIBLE.

STATIC VOLTAGE

IN THREE-PHASE PAD-MOUNTED TRANSFORMERS IF ONE PHASE IS OPEN ON THE PRIMARY SIDE YOU MAY STILL GET STATIC VOLTAGE READINGS ON THE SECONDARY SIDE OF THE TRANSFORMER DUE TO MAGNETIC FLUX. ANYTIME YOU GET ABNORMALLY HIGH SECONDARY VOLTAGE READINGS ON THE SECONDARY SIDE OF A THREE-PHASE PAD-MOUNTED TRANSFORMER, THE TRANSFORMER MAY BE SINGLEPHASING.

RADIAL FEED TRANSFORMERS ARE NONSTANDARD AND WILL NO LONGER BE PURCHASED.

SECONDARY BUSHING/TERMINALS

1. THE OVERSIZED SECONDARY TERMINALS WE USE PROVIDE A LONG LEVER ARM AND MAKE BREAKAGEOF THE SECONDARY BUSHING EASY. IF EXCESS FORCE IS APPLIED TO THE TERMINAL WHEN CONNECTINGCABLES YOU WILL BREAK THE SECONDARY BUSHING. PLEASE EXERCISE CARE WHEN TIGHTENING UPSECONDARY CABLES.

2. THE PRESENT SECONDARY TERMINALS WE USE ARE PINNED TO THE BUSHING STUD IN ADDITION TOHAVING A JAM NUT. OLDER SECONDARY BUSHINGS DO NOT HAVE THIS JAM NUT. IT IS POSSIBLE TOLOOSEN THE TERMINAL/JAM NUT WHEN CONNECTING CABLES TO THIS UNPINNED TERMINAL. ALWAYSCHECK AND TIGHTEN THE JAM NUT AFTER YOU HAVE FINISHED CONNECTING UP THE CABLES.

EMERGENCY CHANGEOUT OF RADIAL FEED UNITS

THREE-PHASEPAD-MOUNTED TRANSFORMERS

GENERAL INFORMATIONREVISED BY CK'D APPR.

DWG.

1

27.06-02

2

3

0 10/29/10 SIMMONS GUINN ELKINS

7/15/11 DANNA BURLISON ELKINS

REVISED BY CK'D APPR.

DWG.

1

27.06-03

2

3

0

CONNECTING PARALLEL SECONDARIES

ANY TIME PARALLEL THREE-PHASE SECONDARY CONDUCTORS ARE RUN TO THE CUSTOMER OR THE CUSTOMERCOMES TO THE SECONDARY TERMINALS OF THE TRANSFORMER, EACH PARALLEL CONDUCTOR SHOULD BE THESAME LENGTH. HOWEVER, EXCESSIVE CONDUCTOR LENGTH SHOULD BE CUT SO THE CONDUCTORS MAKE ANEAT, SAFE FIT TO THE SECONDARY TERMINALS. WHEN CUTTING OFF EXCESS CONDUCTORS, DIFFERENT LENGTHSCAN BE TRIMMED FROM THE THREE-PHASE CONDUCTORS OR THE NEUTRAL, AS LONG AS ALL CONDUCTORS ON

SINGLE PHASING

PAD-MOUNTED TRANSFORMERS SHOULD NOT BE LEFT TO SINGLE PHASE FOR LONG PERIODS OF TIME. SINGLEPHASING IS AN OUTAGE CONDITION AND SHOULD BE TREATED AS SUCH. PAD-MOUNTED TRANSFORMERSSUBJECTED TO EXTENDED PERIODS OF SINGLE PHASING WILL OVERHEAT DUE TO CIRCULATING MAGNETICCURRENTS.

THE SAME PHASE ARE THE SAME LENGTH.

CABLES SHOULD BE BENT AT THE BOTTOM OF THE SECONDARY COMPARTMENT AND TRAINED TO COME UPSTRAIGHT UNDER THE SECONDARY BUSHING WHERE THEY ARE TO BE CONNECTED. THERE SHOULD BE ENOUGHSLACK IN THE CABLES TO ALLOW FOR TRENCH SETTLEMENT. CUT THE CABLES TO PROPERLY FIT AT THESECONDARY BUSHINGS. ATTACH THE CABLES TO THE SET SCREW BLOCKS STARTING AT THE BACK OF THESECONDARY BUSHING.

6/29/10

THREE-PHASE PAD-MOUNTEDTRANSFORMER (CONT.)GENERAL INFORMATIONSIMMONS GUINN ELKINS

7/15/11 DANNA BURLISON ELKINS

FAULT INDICATORS

THREE-PHASE TRANSFORMERS - MANUAL FAULT INDICATORS SHALL BE INSTALLED ON THE LOAD SIDE PRIMARYCABLES WHEN THE TRANSFORMER IS WITHIN A LOOP SYSTEM OR ON A RADIAL SYSTEM CONTAINING MORE THANONE TRANSFORMER. FAULT INDICATORS ARE NOT REQUIRED ON A SINGLE, RADIAL-FED, THREE-PHASE

SEE DWG. 26.07-08 FOR MORE DETAIL.

8/15/11 SIMPSON SIMPSON ELKINS

ALL CONDUCTORSOF THE SAME PHASEOR NEUTRAL MUSTBE THE SAME LENGTH

TRANSFORMER.

BUILDING WALL

TRANSFORMER PAD

TRANSFORMER

1'-0"1'-0"

4'-0"

3'-0" 4" GALV.STEEL CONDUIT CUT TO

7'-0" LENGTH

FILL 12" DIA.MIN. HOLE AND 4"

DIA. CONDUIT WITH3000 PSI CONCRETEROUND FORM TOP

AND SLOPECONCRETE AT BASE OF POLE

SEE NOTE 1

PLAN VIEW

3" MIN.CONCRETE

STANDARD POLE

DWG.

27.06-06

ALL AROUND

ALL AROUND

REMOVABLE POLE

CONCRETE3" MIN.

BASE OF POLECONCRETE AT

AND SLOPEROUND FORM TOP

3000 PSI CONCRETEDIA. CONDUIT WITH

HOLE AND 4"FILL 12" DIA. MIN.

7'-0" LENGTHSTEEL CONDUIT CUT TO

4" GALV.

3'-0"

4'-0"

NOTES:

2. TRANSFORMER PROTECTION POLES SHOULDBE INSTALLED ON ALL SIDES OF THE TRANSFORMER WHICH ARE SUBJECT TO VEHICULAR TRAFFIC.

3. POLES SHOULD BE PAINTED YELLOW.

4. THESE PROTECTIVE POLES SHALL BE PROVIDEDAND INSTALLED BY THE CUSTOMER.

5" SCH 80 PVC CONDUIT CUT TO

3'-0" LENGTH

6" COMPACTEDSTONE OR GRAVEL

5. CUSTOMER MAY PROVIDE AN ALTERNATE DESIGNFOR A REMOVABLE BARRIER, BUT MUST BEAPPROVED BY THE FIELD ENGINEER.

1'-0"

MAX. 4'-10" MAX. 4'-10"

10/29/10

PROTECTIVE POLES FOR OIL FILLED

PAD-MOUNTED TRANSFORMERSSIMMONS GUINN ELKINS

CN 380216

CN 380216

0

3

2

1

APPR.REVISED BY CK'D

6. ANY SINGLE AND THREE-PHASE PAD-MOUNTED TRANSFORMERS THAT ARE EXPOSED TO PAVED AREAS AND/OR VEHICULAR TRAFFIC SHALL BE HAVE PROTECTIVE BARRIERS PROVIDED AND INSTALLED BY THE CUSTOMER.

SEE NOTE 77. CN 9220151882 (6"X6"X8' CONCRETE POST, GRAY IN COLOR) IS AVAILABLE AS A PROTECTIVE POLE. EXPOSED PART OF POLE TO BE PAINTED WITH "HIGHWAY YELLOW" (OR SIMILAR YELLOW COLOR) CONCRETE PAINT.

1. ON THREE-PHASE PAD-MOUNTED TRANSFORMERS,

2'-0" IN FRONT OF THE TRANSFORMERBETWEEN THE DOORS TO ACCOMMODATETHE DOOR SWING AND SHALL BE REMOVABLE.

THIS POLE SHOULD BE CENTRALLY LOCATED

POLE SHOULD BE LOCATED APPROXIMATELY3'-6" IN FRONT OF THE TRANSFORMER (NO

ON SINGLE-PHASE TRANSFORMERS, THIS

LESS THAN 3').

5'-2"MAXIMUM

5'-2"MAXIMUM

1/27/12 SIMPSON SIMPSON ELKINS

X0

X1 X3

X2

NOTES:

DWG.

27.06-304/13/11 DANNA BURLISON ELKINS

THREE-PHASE TRANSFORMER CONNECTION TO

SINGLE-PHASE TRANSFORMER

1. INSTALL FEED THRU INSERT ON C PHASE OF #2 SIDE (LOAD SIDE) OF THREE-PHASE TRANSFORMER TO

0

3

2

1

APPR.REVISED BY CK'D

H 0 /

X

XFMRPAD

TO

XXXX

2. SINGLE-PHASE TRANSFORMER TO BE RADIAL FED AND LOCATED WITHIN 50' OF THREE-PHASE TRANSFORMER.

FEED THRUINSERT

TO SINGLE-PHASETRANSFORMER

ELBOW ARRESTER

TO THREE-PHASETRANSFORMER

PREVENT CONFLICTS WITH OTHER PHASES DURING SWITCHING.

H1A

H1B

11/11/11 DANNA

3. INSTALL FAULT INDICATOR ON SINGLE-PHASE RADIAL TAP.

BURLISON ELKINS