Page 1
.c
om
DB 46-356
Westinghouse
Type E F D Switch
•
For Pad Mounted Distribution
Transformers
Westinghouse type
EFD
load-break
ua
ls
The
switch is specifically designed to meet the
full switching requirements of underground
distribution systems utilizing pad-mounted
transformers.
The EFD is available on single phase or three
phase pad mounted transformers. It is appli­
cable on 15 kv class grounded wye systems
for either loop-feed or radial-feed distribution.
Features
Dead-Front Type Construction
Simplified Operation
Externally Fusible
Load Break
Compact Construction
Schematic Diagram Decals
Single Phase or Three Phase Application
Loop-Feed or Radial-Feed Application
Current Limiting Fusing
Construction
The EFD switch poles, housing, and all
structural pans are high pressure molded
of glass polyester, a thermosetting material,
which affords the switch greater structural
and dimensional stability. Glass polyester
incorporates high dielectric strength, track­
resistance, and durability, Nylon screws are
used in assembly of the switch poles.
All current carrying pans are made of copper
with both stationary and moving contacts
silver plated to meet ASA temperature rise
requirements.
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w
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lec
tri
ca
lP
ar
tM
an
To fulfill these requirements, the EFD incor­
porates two major benefits in its design­
switching flexibility and safety. These bene­
fits are made possible by a compact, "dead­
front" type construction that enables the
EFD switch to be externally mounted on the
transformer.
May. 1967
Supersedes DB 46-356 dated May, 1966
E, D. C/2062/DB
Page 2
.c
om
DB 48-358
Westinghouse
•
Fuse Protection
ua
ls
A sealed, current-limiting, silver-sand fuse,
is normally provided for the transformer­
connecting pole.
The fuse is mounted within the housing of
the center switch pole so that the switch can
be re-fused safely, away from the high volt­
age contacts.
an
The EFD fuse is a full-range clearing fuse,
capable of safely interrupting up to 25,000
amps symmetrical, 40,000 amps asymmet­
rical for all voltage ratings. The sealed, EFD
fuse does not expel gases or create noise,
even during the interruption of high fault
currents.
The fuse is available for single phase trans­
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lec
Fuse
tri
ca
lP
ar
tM
former ratings 25 kva through 167 kva and
for three phase ratings through 300 kva,
connected for grounded wye operation at
2400. 4800, 8000, and 15000 volts.
Spring-loaded Arc Quanching Plate
Page 3
.c
om
DB 46-356
Type EF D Switch
For Pad Mounted Distribution
Transformers
Switching
Load-Breaking
The three poles of the EFD switch may be
opened or closed in a varied order to provide
the following operating positions:
The switching flexibility of the EFD is com­
bined with a high performance load break
capability.
1. Loop-feed throug h; transformer ener­
gized.
When a switch pole is drawn out and the
contacts separate, the circuit is broken in
two places, creating two series arcs. Two
sets of spring-loaded, arc quenching plates
extinguish the arc within two or three half
cycles. The quench plates are molded of a
glass polyester material that generates a de­
ionizing gas in the presence of an arc. The
gas extinguishes the arc. This glass polyester
has such durability that repeated operation
under load has failed to cause any noticeable
wear. All three switch poles have this load
break capability.
4. Transformer fed from the right; left side
of the loop opened.
5. Loop broken at transformer.
ua
ls
In addition to reliability, an important safety
feature is inherent in the EFD fowitch design.
Should the switch pole be opened on a fault
current higher than can be interrupted, the
pole connector can be immediately rein­
serted, without resetting operations or special
equipment. Safe switch reclosing is made
possible by a 5,000 ampere close-in rating.
ar
The five switching positions of the EFD
switch permit alternate feed for each trans­
former in the loop circuit in case of a line
fault or outage. In the event of a line fault,
the EFD switch may be operated to isolate
the fault, while still providing complete cus­
tomer service.
an
3. Transformer fed from the left; right side
of the loop opened.
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2. Loop-feed through; transformer iso­
lated.
Alternate Design
lP
The Westinghouse EFD switch is designed
to exceed the following performance char­
acteristics:
For three phase, radial-feed, three single
poles and mounting boxes are provided for
each phase line. Each switch pole is mount­
ed on a standoff insulator and a through­
type bushing. In this manner, three phase
transformers can be disconnected from a
radial feed circuit.
Three Phase Application
ca
Continuous Current Rating .. .200 Amperes
load- Break Rating® .
.. .
200 Amperes
Close-in Rating . .. . . . .5,000 Amperes
Momentary Rating ... .
10,000 Amperes
Insulation Rating ..
. .
. .95 Kv Bil
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
(j) At 70% Power Factor or higher
tri
Cable Connections
.E
lec
Operation of the EFD switch is made safe
and convenient by its simplified construc­
tion.The switch contacts can be opened by
simply drawing out the insulated switch
poles so that they are completely free of the
switch housing. This leaves a clearly visible
disconnect.
The contacts are recessed within the main
switch housing. Thus. during the interrup­
tion of current. the arc is completely con­
tained within the switch housing until it is
quenched. Furthermore, hazards due to
open, exposed contacts, are greatly reduced.
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The switch poles are drawn out or inserted
with an ordinary hookstick. No resetting
operation is necessary before insertion of
the switch pole.
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For added safety, a schematic diagram decal
mounted on the front of the switch, insures
operating personnel of proper switching
operation.
High voltage feeder cables are connected
to the left and right switch contacts by means
of solderless. clamp-type connectors.These
connectors are capable of accepting cable
sizes ranging from 1116 to 111 4/0.
A grounding pole is also available to protect
lineman working around the transformer
compartment. The construction of the
grounding pole is similar to that of the
switch poles. However, the grounding pole
serves to insulate the switch contacts rather
than connect them. In addition, the ground­
ing pole actually serves as a physical barrier
to prevent lineman from touching the ener­
gized upper switch contact. A copper stud,
connected to the lower switch contact and
feeder cable, extends through the face of
the grounding pole. A grounding clamp can
be attached to the extended copper stud.
Thus, when a lineman wants complete assur­
ance that a high voltage cable is de-energized,
he merely draws out the switch pole; inserts
the grounding pole in its place; and at­
taches a grounding clamp to the copper
stud and to ground.
For three phase, loop-feed systems, three
EFD switches can be mounted together to
provide the five switching positions for each
of the three phase lines. Either arrangement,
loop-feed or radial-feed, provides the same
f lexibility and the high performance charac­
teristics of the single phase EFD applications.
Page 4
.c
om
DB 46-366
Type EFD Switch
For Pad Mounted Distribution
Transformers
1000
1000
I
5
500
ua
ls
Performance Curves
500
200
100
100
50
50
20
20
10
5
10
5
2
2
tM
an
200
I
.5
.5
.2
<II
'"
'C
c:
0
(J
..,
(/)
.5
.=
:E .02
..,
.01.0
0
- 0
(\/
o
10
00
0
- 0
(\/
8gg
Q �
10
Current In Amperes
00 0
o
E
i=
lP
i=
.I
ar
1!
.1
8
.05
:;
.2
8
.05
.02
.01
� � § §�
10
Melt-Time Current Characteristic Curves for EFD Switch
Current Limiting Fuses, Curve No. 562761
-
(\/
10
0
- 0 0 0 0 0 0 0 00
(\/
10 Q
00
� g
00..
IOQ
�
Current In Amperes
Q
ca
(\/
�
2
Melt-Time Current Characteristic Curves for EFD Switch
Current Limiting Fuses, 15 Kv Rating
Minimum melt time shown by curves; maximum clearing time is
tri
melt time plus 20%
Fuse Style and Continuous Current Rating
:
Kva
..
_�
i
! 4160.4800
2400
Single Phase
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I
Volt� _�..
678C248G05
678C249G02
678C276G02
678C276G05
680C386G02
680C386G03
.E
678C276G01 (18)
678C276G04 (25)
678C277G04 (30)
678C282GOl (75)
678C282GOl (75)
680C387GOl (150)
15+25
3 7Y..
50
75
100
167
(8)
(12)
(18)
(25)
(30)
(60)
7200,7620.8000
678C248G03
678C248G06
591C273G03
678C276G03
678C276G06
680C386GOl
(5)
(8)
(12)
(18)
(25)
(30)
I
15000
678C295G05 (4)
678C295G04 (5)
678C295G03 (8)
678C295G02 (12)
678C295G02 (12)
678C295G07 (18)
Fuse Style and Continuous Current Rating - Three Phase
Kva
Voltage
2400A
678C276GOl (18)
678C277G04 (30)
678C282GOl (75)
678C282GOl (75)
678C282G01 (75)
680C387GOl (150)
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45
75
112%
150
225
300
I
I
I
4160Y/2400
678C276GOl
678C276GOl
678C276G04
678C277G04
678C282G01
678C282GOl
(18)
(18)
(25)
(30)
(75)
(75)
678C249G02
678C276G02
678C276G05
680C386G02
680C386G03
680C386G03
Westinghouse Electric Corporation
Distribution Transformer Division, Sharon, Pa. 16146
Printed in USA
I
4160 4800A
(12)
(18)
(25)
(30)
(60)
(60)
I
nOOA
678C248G03 (5)
591C273G03 (12)
678C276G03 (18)
678C276G06 (25)
680C386GOl (30)
680C386G01 (30)
I
12470Y/1200
678C248G03 (5)
678C248G03 (5)
678C248G06 (8)
591 C273G03 (12)
678C276G03 (18)
678C276G06 (25)
I
12000
to 150004.
678C295G05 (4)
678C295G03 (8)
678C295G02 (12)
678C295G02 (12)
678C295G07 (18)
678C295G07 (18)
I
24940 Gnd Y/14400
678C295G05 (4)
678C295G05 (4)
678C295G04 (5)
678C295G03 (8)
678C295G02 (12)
678C295G02 (12)
Page 1
.c
om
DB 46-356
Westinghouse
Type E F D Switch
•
For Pad Mounted Distribution
Transformers
ua
ls
The Westinghouse type EFD load-break
switch is specifically designed to meet the
full switching requirements of underground
distribution systems utilizing pad-mounted
transformers.
To fulfill these requirements, the EFD incor­
porates two major benefits in its design­
switching flexibility and safety. These bene­
fits are made possible by a compact, "dead­
front" type construction that enables the
an
EFD switch to be externally mounted on the
transformer.
phase pad mounted transformers. It is appli­
cable on 15 kv class grounded wye systems
for either loop-feed or radial-feed distribution.
Features
Dead-Front Type Construction
Simplified Operation
Externally Fusible
Load Break
Compact Construction
Schematic Diagram Decals
Single Phase or Three Phase Application
Loop-Feed or Radial-Feed Application
Current Limiting Fusing
Construction
The EFD switch poles, housing, and all
structural parts are high pressure molded
of glass polyester, a thermosetting material.
which affords the switch greater structural
and dimensional stability. Glass polyester
incorporates high dielectric strength, track­
resistance. and durability. Nylon screws are
used in assembly of the switch poles.
All current carrying parts are made of copper
with both stationary and moving contacts
silver plated to meet ASA temperature rise
requirements.
ww
w
.E
lec
tri
ca
lP
ar
tM
The EFD is available on single phase or three
May. 1967
Supersedes DB 46-356 dated May. 1966
E. D. C/2062/D B
Page 2
.c
om
DB 46-356
Westinghouse
•
ua
ls
Fuse Protection
A sealed, current-limiting, silver-sand fuse,
is normally provided for the transformer­
connecting pole.
The fuse is mounted within the housing of
the center switch pole so that the switch can
b e re-fused safely, away from the high volt­
age contacts.
The EFD fuse is a full-range clearing fuse,
capable of safely interrupting up to 25,000
an
amps symmetrical, 40,000 amps asymmet­
rical for all voltage ratings. The sealed, EFD
fuse does not expel gases or create noise,
even during the interruption of high fault
currents.
The fuse is available for single phase trans­
ww
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.E
lec
EFD Fuse
tri
ca
lP
ar
tM
former ratings 25 kva through 167 kva and
for three phase ratings through 300 kva,
connected for grounded wye operation at
2400, 4800, 8000, and 15000 volts.
Spring-loaded Arc Quenching Plate
Page 3
.c
om
DB 46-356
Type EF D Switch
For Pad Mounted Distribution
Transformers
Switching
Load- Breaking
The three poles of the EFD switch may be
opened or closed in a varied order to provide
The switching flexibility of the EFD is com­
bined with a high performance load break
capability.
ua
ls
Alternate Design
the following operating positions:
1. loop-feed through; transformer ener­
When a switch pole is drawn out and the
contacts separate, the circuit is broken i n
two places, creating two series arcs. Two
gized.
2. loop-feed through; transformer iso­
sets of spring-loaded, arc quenching plates
extinguish the arc within two or three half
lated.
3. Transformer fed from the left; right side
of the loop opened.
an
cycles. The quench plates are molded of a
glass polyester material that generates a de­
ionizing gas in the presence of an arc. The
of the loop opened.
4. Transformer fed from the right; left side
The five switching positions of the EFD
gas extinguishes the arc.This glass polyester
has such durability that repeated operation
under load has failed to cause any noticeable
switch permit alternate feed for each trans­
former in the loop circuit in case of a line
break capability.
5. loop broken at transformer.
tM
wear. All three switch poles have this load
fault or outage. In the event of a line fault,
the EFD switch may be operated to isolate
the fault while still providing complete cus­
In addition to reliability, an important safety
feature is inherent in the EFD switch design.
Should the switch pole be opened on a fault
current higher than can be interrupted, the
For three phase, radial-feed, three single
poles and mounting boxes are provided for
pole connector can be immediately rein­
serted, without resetting operations or special
equipment. Safe switch reclosing is made
ed on a standoff insulator and a through­
type bushing. In this manner, three phase
ar
tomer service.
possible by a 5,000 ampere close-in rating.
lP
The Westinghouse EFD switch is designed
to exceed the following performance characteristics:
each phase line. Each switch pole is mount­
transformers can be disconnected from a
radial feed circuit.
Three Phase Application
Continuous Current Rating ...200 Amperes
load- Break RatingCD . . • . . . . . 200 Amperes
ca
Close-in Rating . . ...... . .5,000 Amperes
Momentary Rating .... . . .10,000 Amperes
Insulation Rating .
.
.
.
.
.
•
.
.
CD At 70% Power Factor or higher
.
.
.
.
95 Kv Bil
tri
Cable Connections
lec
High voltage feeder cables are connected
Operation of the EFD switch is made safe
and convenient by its simplified construc­
tion. The switch contacts can be opened by
.E
simply drawing out the insulated switch
poles so that they are completely free of the
switch housing.This leaves a clearly visible
disconnect.
The contacts are recessed within the main
switch housing. Thus, during the interrup­
tion of current, the arc is completely con­
to the left and right switch contacts by means
of solderless, clamp-type connectors.These
connectors are capable of accepting cable
sizes ranging from %>6 to #4/0.
A grounding pole is also available to protect
lineman working around the transformer
compartment. The construction of the
grounding pole is similar to that of the
switch poles. However, the grounding pole
serves to insu late the switch contacts rather
than connect them. In addition, the ground­
ing pole actually serves as a physical barrier
tained within the switch housing until it is
to prevent lineman from touching the ener­
gized upper switch contact. A copper stud,
quenched. Furthermore,
connected to the lower switch contact and
hazards
due
to
open, exposed contacts, are greatly reduced.
feeder cable, extends through the face of
The switch poles are drawn out or inserted
the grounding pole.A grounding clamp can
be attached to the extended copper stud.
w
with an ordinary hookstick. No resetting
operation is necessary before insertion of
the switch pole.
For added safety, a schematic diagram decal
ww
Thus, when a lineman wants complete assur­
ance that a high voltage cable is de-energized,
he merely draws out the switch pole; inserts
mounted on the front of the switch, insures
the grounding pole in
operating personnel of proper
taches a grounding clamp to the copper
operation.
switching
stud and to ground.
its place; and at­
For three phase, loop-feed systems, three
EFD switches can be mounted together to
provide the five switching positions for each
of the three phase lines. Either arrangement,
loop-feed or radial-feed, provides the same
flexibility and the high performance charac­
teristics of the single phase EFD applications.
Page 4
.c
om
DB 46-356
Type EF D Switch
For Pad Mounted Distribution
Transformers
,�,
1000
I�\'\ \ {'
•
200
.
.
\
500
200
100
\\ 1\ GO\
!�\ \
\
10
XW \�
\\\
�
\\\\\\\ 1 �\
\ \\\\
\ \\
"'
5
2
.5
\
20
an
20
50
10
.
5
2
tM
50
I
.5
\
.2
.I
(/)
'0
c
0
t>
Ql
(/)
.01
10 o
-
0
N
\
o 0
10 Q
8
10
0
0
N
0
0
Q
0
0
0
0
o
0
0
8
§-
10
N
.E
..,
E
i=
0
0
80
.05
.02
.01
� �6
N
IOQ
ca
Current In Amperes
.1
lP
\
.02
.2
ar
'
.. .05
(/)
.E
..
E
i=
"
\\' \
� \
100
en
'0
c
0
t>
1000
\�. \ <" \
500
,1;;
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ls
Performance Curves
Melt-Time Current Characteristic Curves for EFD Switch
Current Limiting Fuses, Curve No. 562761
(.') -
N
to
Q
@
o
ID
0
Q
Current In Amperes
0
O
C\l
0
0
ID
0
0
Q
80
N
o
0
� �
�,
Melt-Time Current Characteristic Curves for EFD Switch
Current Limiting Fuses, 15 Kv Rating
Minimum melt time shown by curves; maximum clearing t ime is
tri
melt time plus 20%
Fuse Style and Continuous Current Rating - Single Phase
I
_V_o_tl �ga �e
�______________�______________�__________
__________
2400
I
4160. 4800
•
I
678C248G05
678C249G02
678C276G02
678C276G05
680C386G02
680C386G03
.E
678C276GOl (18)
678C276G04 (25)
678C277G04 (30)
678C282GOl (75)
678C282G01 (75)
680C387G01 (150)
15+25
37%
50
75
100
167
I
lec
Kva
(8)
(12)
(18)
(25)
(30)
(60)
I
7200, 7620, 8000
678C248G03
678C248G06
591C273G03
678C276G03
678C276G06
680C386G01
(5)
(8)
(12)
(18)
(25)
(30)
I
15000
_
678C295G05 (4)
678C295G04 (5)
678C295G03 (8)
678C295G02 (12)
678C295GOZ (12)
678C295G07 (18)
Fuse Style and Continuous Current Rating - Three Phase
Kva
Voltage
2400Ll
!
678C276G01
I 678C277G04
: 678C282G01
678C282GOl
678C282GOl
680C387GOl
I
(18)
(30)
(75)
(75)
(75)
(150) I
ww
w
45
75
112%
150
225
300
i
4160Y/2400
I
678C276GOl
678C276GOl
678C276G04
678C277G04
678C282GOl
678C282GOl
(18)
(18)
(25)
(30)
(75)
(75)
Westinghouse Electric Corporation
678C249G02
678C276G02
678C276G05
680C386G02
680C386G03
680C386G03
Distribution Transformer Division, Sharon, Pa. 16146
Printed in
USA
I
4160,480011
(12)
(1 S)
(25)
(30)
(60)
(60)
7200:>
678C248G03
591C273G03
678C276G03
678C276G06
680C386GOl
680C386G01
i 124 70Y/7200
(5)
(12)
(18)
(25)
(30)
(30)
678C248G03 (5)
678C248G03 (5)
678C248G06 (8)
591C273G03 (12)
678C276G03 (18)
678C276G06 (25)
12000 to 150006.
24940 Gnd Y/14400
678C295G05
678C295G03
678C295G02
678C295G02
678C295G07
678C295G07
678C295G05 (4)
678C295G05 (4)
678C295G04 (5)
678C295G03 (8)
678C295G02 (12)
678C295G02 (12)
(4)
(8)
(12)
(12)
(18)
(18)