S&C Vista® Underground For Undercover™, Vault-Mounted, and

Distribution Switchgear Pad-Mounted Styles

Instructions For SF6 Refill Kit

Table of Contents
Section Page Section Page

Introduction Safety Information

Qualified Persons. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Understanding Safety-Alert Messages. . . . . . . . . . . . 3
Read this Instruction Sheet . . . . . . . . . . . . . . . . . . . . 2 Following Safety Instructions. . . . . . . . . . . . . . . . . . . 3
Retain this Instruction Sheet. . . . . . . . . . . . . . . . . . . 2 Replacement Instructions and Labels . . . . . . . . . . . . 3
Proper Application . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Operation
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Refill Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

October 15, 2018

©  S&C Electric Company 1997-2018, all rights reserved Instruction Sheet  681-520
Introduction

Qualified Persons
 WARNING
Only Qualified Persons who are knowledgeable in the installation, operation, and
maintenance of overhead and underground electric distribution equipment, along
with all associated hazards, may install, operate, and maintain the equipment
covered by this publication. A Qualified Person is someone who is trained and
competent in:
• The skills and techniques necessary to distinguish exposed live parts from nonlive
parts of electrical equipment
• The skills and techniques necessary to determine the proper approach distances
corresponding to the voltages to which the Qualified Person will be exposed
• The proper use of special precautionary techniques, personal protective
equipment, insulated and shielding materials, and insulated tools for working on
or near exposed energized parts of electrical equipment
These instructions are intended ONLY for such Qualified Persons. They are
not intended to be a substitute for adequate training and experience in safety
procedures for this type of equipment.

Read this
NOTICE
Instruction Sheet
Thoroughly and carefully read this instruction sheet and all materials included in
the product’s S&C Instruction Handbook before installing or operating your S&C
Vista Underground Distribution Switchgear. Familiarize yourself with the Safety
Information and Safety Precautions sections on pages 3 and 4. The latest version
of this publication is available online in PDF format at sandc.com/en/support/
product-literature/.

Retain this This instruction sheet is a permanent part of your SF6 refill kit for use with S&C Vista
Instruction Sheet Underground Distribution Switchgear. Designate a location where you can easily retrieve
and refer to this publication.

Proper Application
 WARNING
The equipment in this publication is only intended for specific applications. The
applications must be within the ratings furnished for the equipment. Ratings for
Vista Underground Distribution Switchgear are listed in Table 1 in Specification
Bulletin 681-31. The ratings are also on the S&C nameplate affixed to the product.

Warranty The warranty and/or obligations described in S&C’s Price Sheet 150 “Standard Conditions
of Sale – Immediate Purchasers in the United States” (or Price Sheet 153, Standard
Conditions of Sale – Immediate Purchasers Outside the United States) plus any special
warranty provisions, as set forth in the applicable product-line specification bulletin,
are exclusive. The remedies provided in the former for breach of these warranties shall
constitute the immediate purchaser’s or end user’s exclusive remedy and a fulfillment of
the seller’s entire liability. In no event shall the seller’s liability to the immediate purchaser
or end user exceed the price of the specific product that gives rise to the immediate
purchaser’s or end user’s claim. All other warranties, whether express or implied or
arising by operation of law, course of dealing, usage of trade or otherwise, are excluded.
The only warranties are those stated in Price Sheet 150 (or Price Sheet 153), and THERE
ARE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. ANY EXPRESS WARRANTY OR OTHER OBLIGATION
PROVIDED IN PRICE SHEET 150 (OR PRICE SHEET 153) IS GRANTED ONLY TO THE
IMMEDIATE PURCHASER AND END USER, AS DEFINED THEREIN. OTHER THAN AN
END USER, NO REMOTE PURCHASER MAY RELY ON ANY AFFIRMATION OF FACT OR
PROMISE THAT RELATES TO THE GOODS DESCRIBED HEREIN, ANY DESCRIPTION
THAT RELATES TO THE GOODS, OR ANY REMEDIAL PROMISE INCLUDED IN PRICE
SHEET 150 (or PRICE SHEET 153.)

2   S&C Instruction Sheet 681-520

 Safety Information

Understanding Several types of safety-alert messages may appear throughout this instruction sheet and
Safety-Alert on labels and tags attached to your S&C Vista Underground Distribution Switchgear.
Familiarize yourself with these types of messages and the importance of these signal
Messages
words:

 DANGER
“DANGER” identifies the most serious and immediate hazards that will likely
result in serious personal injury or death if instructions, including recommended
precautions, are not followed.

 WARNING
“WARNING” identifies hazards or unsafe practices that can result in serious
personal injury or death if instructions, including recommended precautions, are
not followed.

 CAUTION
“CAUTION” identifies hazards or unsafe practices that can result in minor personal
injury if instructions, including recommended precautions, are not followed.

NOTICE
“NOTICE” identifies important procedures or requirements that can result in
product or property damage if instructions are not followed.”

Following Safety If you do not understand any portion of this instruction sheet and need assistance, contact
Instructions your nearest S&C Sales Office or S&C Authorized Distributor. Their telephone numbers
are listed on S&C’s website sandc.com. Or call the S&C Global Monitoring and Support
Center at 1-888-762-1100.

NOTICE

Read this instruction sheet thoroughly and

carefully before refilling your S&C Vista
Underground Distribution Switchgear.

Replacement If you need additional copies of this instruction sheet, contact your nearest S&C Sales
Instructions Office, S&C Authorized Distributor, S&C Headquarters, or S&C Electric Canada Ltd.
and Labels It is important that any missing, damaged, or faded labels on the equipment be replaced
immediately. Replacement labels are available by contacting your nearest S&C Sales
Office, S&C Authorized Distributor, S&C Headquarters, or S&C Electric Canada Ltd.

S&C Instruction Sheet 681-520   3

Safety Precautions

  DANGER
Switchgear contains high voltage. Failure to observe these Safety Precautions
will result in serious personal injury or death.
Some of these precautions may differ from your company’s operating procedures
and rules. Where a discrepancy exists, follow your company’s operating procedures
and rules.

1. QUALIFIED PERSONS. Access to switchgear must serviced, or repaired, always disconnect load-
be restricted only to qualified persons. See “Qualified inter­
rupter switches and fault interrupters from all
Persons” on page 2. power sources (including backfeed), test for voltage,
2. SAFETY PROCEDURES. Always follow safe and properly ground.
operating procedures and rules. 9. TESTING. Test the bushings for voltage using the
3. PERSONAL PROTECTIVE EQUIPMENT. Always volt­age-indication feature (if furnished) or other proper
use suitable protective equipment such as rubber high-voltage test equipment before touching any
gloves, rubber mats, hard hats, safety glasses, and bush­ings or components inside the switchgear tank
flash clothing, in accordance with safe operating that are to be inspected, replaced, serviced, or
procedures and rules. repaired.

4. SAFETY LABELS. Do not remove or obscure any of 10. GROUNDING. Make sure the switchgear tank and
the “DANGER,” “WARNING,” “CAUTION,” or pad-mounted enclosure (if furnished) are properly
“NOTICE” labels. grounded to the station or facility ground. After the
switchgear has been completely disconnected from
5. CLOSING AND LOCKING ENCLOSURES. The pad- all sources of power and tested for voltage, properly
mounted enclosure (if furnished) must be securely ground the load-interrupter switches and fault
closed with padlocks in place at all times unless work interrupters before touching any bushings or
is being performed inside the enclosure. components inside the switchgear tank that are to be
6. ENERGIZED BUSHINGS. Always assume the inspected, replaced, serviced, or repaired.
bushings are energized unless proved otherwise by 11. LOAD-INTERRUPTER SWITCH AND FAULT
test, by visual evidence of an open-circuit condition at INTERRUPTER POSITION. Always confirm the
the load-interrupter switch or fault interrupter, or by Open/Close/Grounded position of load-interrupter
observing that the load-interrupter switch or fault switches and fault interrupters by visually observing
interrupter is grounded. the position of the blades. Load-interrupter switches
7. BACKFEED. Load-interrupter switches and fault and fault interrupters may be energized by backfeed.
interrupters may be energized by backfeed. Load-interrupter switches and fault interrupters may
be energized in any position.
8. DE-ENERGIZING, TESTING, AND GROUNDING.
Before touching any bushings or components inside 12. MAINTAINING PROPER CLEARANCE. Always
the switchgear tank that are to be inspected, replaced, maintain proper clearance from energized bushings.

4   S&C Instruction Sheet 681-520

 Operation

General stripe zone. If the gauge indicates pressure has dropped

Vista Underground Distribution Switchgear has been to the red zone, the tank may have absorbed moisture and
carefully designed to provide extremely reliable gas must be evacuated prior to refilling. If this is necessary
seals. Gas leaks are expected to be extremely rare. Gas the unit should be returned to S&C for repair and rework.
pressure is indicated by the internal pressure gauge. The Even if the gauge is not yet in the red zone, any loss of gas
unit can be operated when the gauge is in the green or should be investigated thoroughly so that the leak can be
green-and-yellow stripe zone but it must be refilled if the repaired before refilling.
needle is in the stripe zone. In the unlikely event a gas Before proceeding to the job site be sure to have an
leak develops, the Vista switchgear tank can be refilled in adequate supply of dry SF6 gas for the unit. The Vista tank
the field if the pressure gauge is in the green-and-yellow contains the following amount of SF6 gas:

Table 1. Available SF6 Gas

Pounds of SF6 gas
Max, kV
3-Way Models 4-Way Models 6-Way Models
17 13 17 25
29 13 17 25
38 15 19 29

It is recommended that 20% more gas than indicated above be available.

S&C Instruction Sheet 681-520   5

Operation

Refill Procedure
Follow these steps to refi ll the Vista tank:
STEP 1. Locate the fi ll port cover in the top front corner
of the operation compartment. Clean off all
debris and dirt in the general area before
removing the plug. Remove the plug using a
screwdriver or S&C fi ll port tool number CU-
5987, turning counterclockwise. See Figures 1
and 2.

Figure 1. Location of fill port.

Fill port

Figure 2. Remove the fill port cover.

6 S&C Instruction Sheet 681-520

 Operation

STEP 2. The Schrader fill valve is located under the fill

port cover. Install the valve extension onto the
Schrader valve. Tighten hand tight. Do not over
tighten. See Figure 3.
STEP 3. Bleed the fill hose on the refill tank by cracking
open the cylinder valve slightly for several
seconds to allow the SF6 gas to fill the hose before
connecting to the Schrader valve and extension.
See Figures 4 and 5. (Note: Step 4 on page 8
includes further operating instructions for the
cylinder and regulator.) Close the valve and
connect the chuck of the hose to the end of the
valve extension. See Figures 4 and 5.

Figure 3. Install the valve extension onto the Schrader valve.

Figure 4. Bleed the fill hose for several seconds to fill the hose
before connecting to the Schrader valve extension.

Figure 5. Connect the fill hose to the Schrader valve extension.

S&C Instruction Sheet 681-520   7

Operation

STEP 4. The regulator valve adjusts the maximum fi ll

pressure. Fill gauge
(a) Turn clockwise until the nut stops further Cylinder
movement to fully open the regulator valve. valve
Regulator valve
(b) Back off one full turn (counterclockwise).
(c) Open the cylinder valve. Turn the regulator valve
clockwise until the fi ll gauge reads approximately
5 to 7 psi. See Figure 6.
STEP 5. Observe the pressure gauge on the Vista switchgear
unit. When in the fully Open position, the regulator
valve is calibrated to not allow fill pressure to
exceed 10 psi. Continue to fill the tank with gas until
the needle is at its fill point, in between the tick Cylinder gauge
marks in the green zone (or for R1 Vista models
rated 15 kV, 12.5 kA Sym., at the fill indicator) and Figure 6. Regulator valve assembly.
then close the cylinder valve. DO NOT OVERFILL.
See Figures 7 and 8.

Fill indicator
Green/Yellow
Green zone zone
Orange
Orange Red zone
zone zone

Red
zone

Green/Yellow Green
zone zone
Fill indicator

Figure 7. Internal gas-pressure gauge for most Vista switchgear Figure 8. Internal gas-pressure gauge for most Vista mod-
models. els rated 15 kV, 12.5 kA sym. short circuit that have catalog
numbers ending in R1.

8 S&C Instruction Sheet 681-520

 Operation

STEP 6. With the cylinder valve closed and the regu lator
valve open, observe the fi ll pressure reading on
the fi ll gauge. When the needle on the gauge in the Fill gauge
tank is in the middle of the green band (indicated
Cylinder
by the tick marks) the pressure should be approxi-
valve
mately 7 psi (or 10 psi for R1 . Vista models rated
15 kV, 12.5 kA Sym.) Use the gauge on the refi ll kit
to verify this. If the gauge does not indicate 7 psi
± 0.5 psi at 72°F (22°C), (if the temperature is not
72°F, consult the temperature/pressure
conversion charts (Tables 2 and 3) to identify the
correct pressure for the ambient temperature),
the gauge in the tank is faulty and the unit should
be taken out of service for repair. See Figure 9. Regulator valve
STEP 7. Remove the fi ll hose chuck from the valve
extension. Figure 9. Regulator valve assembly.
STEP 8. Unscrew the valve extension from the Schrader
valve.
STEP 9. Remove any dirt or debris in the fi ll port area.
Inspect the fi ll port cover and O-rings to be sure
they are clean and the O-ring is not damaged. If
the O-ring is damaged, replace it before re-
installing the cover. Re-install the fi ll port cover
over the Schrader valve.

Table 2. Temperature/Pressure Conversion Chart for

most Vista Switchgear Models
Temperature Nominal Pressure (psig)
3300 ft.
Degrees, F Degrees, C Sea Level
(1006 m)
131 55 9 .5 11 .2
122 50 9 .1 10 .8
104 40 8 .4 10 .0
86 30 7 .6 9 .3
68 20 6 .9 8 .6
50 10 6 .2 7 .8
32 0 5 .4 7 .1
14 -10 4 .7 6 .4
-4 -20 4 .0 5 .6
-22 -30 3 .2 4 .9
-40 -40 2 .5 4 .2

S&C Instruction Sheet 681-520 9

Operation

Table 3. Temperature/Pressure Conversion Chart for

Vista Switchgear Models Rated 15 kV, 12.5 kA Sym.
Short Circuit with Catalog Numbers Ending in R1

Temperature Nominal Pressure (psig)

3300 ft.
Degrees, F Degrees, C Sea Level
(1006 m)
131 55 13.0 14.6
122 50 12.5 14.2
104 40 11.7 13.4
86 30 10.8 12.5
68 20 10.0 11.7
50 10 9.2 10.8
32 0 8.3 10.0
14 -10 7.5 9.1
-4 -20 6.6 8.3
-22 -30 5.8 7.5
-40 -40 4.9 6.6

Note: Tables 2 and 3 are to be used when reading the

external pressure gauge on the refill kit as noted in Step 6
of the refill instructions. Nomi­nal readings are 7 ± 0.5 psi
at 72°F (22°C) when the needle on the internal gauge is in
between the tick marks in the green zone. For other tem­
peratures, this chart can be used to convert the reading.
For example, for a unit of non-R1 switchgear (Table 2) at
52°F (11°C) the external gauge should read between 6.2
and 6.9 psi to indicate the internal gauge is functioning
properly.

10   S&C Instruction Sheet 681-520