SIEMENS Sentron Low Amp Busway System User Guide
- June 10, 2024
- SIEMENS
Table of Contents
For Global Power Distribution Applications
Sentron’ Busway Systems
Selection and Application Guide
Sentron Low Amp Busway System
Sentron Low Amp Busway System
225-800Amp
Sentron Low Amp Busway
Warehouse Stock
Sentron Low Amp Busway
Sentron Low Amp busway is available from warehouse stock in a wide offering of
straight sections and fittings essential for completing busway runs. Ordering
from stock, can save the contractor both time and money over cable and
conduit. Aluminum 3-phase, 3-wire and 3-phase, Sentron Low Amp Busway 4-wire
busway is available from 225 amps to 600 amps. Copper 3-phase, 3-wire and
3-phase, 4-wire busway is available from 225 amps to 800 amps. Copper also
avail- able with integral or internal ground. All
warehouse stock is rated IP40. The chart to the right lists straight sections
and fittings available through warehouse stock.
Sentron Low Amp Warehouse Stock
Ampere Rating| Description| Aluminum| Copper
---|---|---|---
225A
| 6ft. Plug-in| ✔| ✔
| 10ft. Plug-in| ✔| ✔
| 5ft. Feeder| N/A| N/A
| 10ft. Feeder| N/A| N/A
| Flat Elbows| ✔| ✔
| EdgeElbows| ✔| ✔
| EndTapBoxes| ✔| ✔
| CenterTapBoxes| ✔| ✔
| FlangedEnds| N/A| N/A
| Flanges| ✔| ✔
| Hangers| ✔| ✔
| EndClosures| ✔| ✔
400A| | |
| 6ft. Plug-in| ✔| ✔
| 10ft. Plug-in| ✔| ✔
| 5ft. Feeder| ✔| ✔
| 10ft. Feeder| ✔| ✔
| Flat Elbows| ✔| ✔
| EdgeElbows| ✔| ✔
| EndTapBoxes| ✔| ✔
| CenterTapBoxes| ✔| ✔
| FlangedEnds| ✔| ✔
| Flanges| ✔| ✔
| Hangers| ✔| ✔
| End Closures| ✔| ✔
600A| | |
| 6ft. Plug-in| ✔| ✔
| 10ft. Plug-in| ✔| ✔
| 5ft. Feeder| ✔| ✔
| 10ft. Feeder| ✔| ✔
| Flat Elbows| ✔| ✔
| EdgeElbows| ✔| ✔
| EndTapBoxes| ✔| ✔
| CenterTapBoxes| ✔| ✔
| FlangedEnds| ✔| ✔
| Flanges| ✔| ✔
| Hangers| ✔| ✔
| End Closures| ✔| ✔
Sentron Low Amp Catalog Numbering System
Straight Sections
Plug-In and Feeder
Sentron Low Amp Busway
Straight Sections
Sentron Low Amp Busway can be ordered with Aluminum or Copper bus bars.
Aluminum bars are available in 225 – 600 ampere sections, and include an
integral housing ground. An optional copper internal or isolated ground bar is
available in 225-800 ampere sections. Copper bars are available in 225-800
ampere sections, and include an integral housing ground. An optional copper
internal ground bar is available. A copper isolated ground bar is available
for 400-800ampere copper busway.
Sentron Low Amp is also available in IEC ratings from 100-630 amperes with
alu- minum bus bars or 100-800 amperes with copper bus bars.
Sentron Low Amp housing is a two-piece extruded aluminum design which is
assembled using a henrob fastening process. The self-piercing rivet technology
is a mechanically applied mixture of zinc, tin and aluminum that coats the
rivet to resist salt, galvanic and other forms of corrosion. The self-piercing
rivets provide optimal structural integrity.
Feeder Sections
Feeder busway carries the current of the busway system from the supply source.
Feeder busway does not have plug-in outlets. Sentron Low Amp IP40 feeder sec-
tions are warehoused in standard lengths. Custom lengths and IP43 and IP54 may
be ordered from the factory. Sentron Low Amp Feeder sections meet IP40
(indoor), IP43 (spray proof), and IP54 (splash proof) requirements. One joint
stack assembly is supplied per feeder section.
Plug-In Sections
Sentron Low Amp plug-in sections are designed with plug-in openings centered
on 24 in. (610mm) intervals. Plug-in openings are staggered on both sides of
the busway for optimum utilization. IP40 plugin sections are warehoused in
standard lengths. Sentron Low Amp plug-in sections meet IP40 (indoor). IP43
(spray proof), and IP54 (splash proof) requirements. One joint stack assembly
is provided per plug-in section.
Plug-In Outlet Features
The plug-in outlet molded guard design prevents incidental finger contact with
live conductors. Sentron Low Amp plug-in outlets are IP 2X rated: a .472 in.
(12mm) test probe is unable to enter a plug-in outlet. Configuration
connections are clearly marked on the plug-in outlet to ensure proper contact
of phase and ground bars with bus plug fingers.
Sentron Low Amp Busway Widths and Weights
Aluminum|
---|---
225| C| 2.7 (4.0)| 3.0 (4.4)| 2.9 (4.3)| 3.1 (4.7)| 3.0 (4.5)| 3.3 (4.9)
400| D| 3.6 (5.4)| 4.1 (6.2)| 3.9 (5.9)| 4.4 (6.6)| 4.2 (6.3)| 4.7 (7.1)
600| E| 5.0 (7.5)| 5.8 (8.7)| 5.6 (8.3)| 6.4 (9.5)| 6.2 (9.2)| 7.0 (10.4)
Copper| | | | | | |
225| A| 2.7 (4.0)| 2.9 (4.2)| 3.0 (4.4)| 3.1 (4.6)| 3.2 (4.8)| 3.4 (5.0)
400| C| 3.8 (5.7)| 4.1 (6.1)| 4.4 (6.5)| 4.6 (6.9)| 4.9 (7.3)| 5.2 (7.7)
600| D| 5.7 (8.5)| 6.2 (9.2)| 6.7 (10.0)| 7.2 (10.7)| 7.7 (11.5)| 8.2 (12.2)
800| E| 9.0 (13.3)| 9.8 (14.5)| 10.8 (16.1)| 11.7 (17.3)| 12.7 (18.9)| 13.5
(20.1)
Elbows and Tees
Sentron Low Amp Busway
Elbows
Sentron Low Amp elbows provide a simple, convenient method of changing the
direction (left, right, up or down) of a busway run. All elbows are shipped
with a joint stack assembly on one end for direct connection to the busway
system. Flatwise elbows are used for left and right directional changes when
the busway system is mounted in the horizontal plane; bus bars run parallel to
the floor. The joint stack assembly may be moved to the opposite leg to change
the orientation from left to right/right to left. Edgewise elbows create up
and down directional changes. The joint stack assembly on edgewise elbows can
not be moved in order to change orientation from up to down/down to up. For
both edgewise and flatwise elbows the sum of the two legs may not exceed 10
ft. (3.05m). See drawings for minimum/standard dimensions.
Tees
Tees are used to simplify directional and plane orientation changes in a
busway system. Tees can make 90° bends left or right and up and down along the
busway run. All tees are supplied with two joint stack assemblies. Flatwise
tees are used to create left and right branches.
Edgewise tees are used to create branches that stem up or down from the busway
run.
Offsets
Offsets
Offsets can be utilized to solve difficult contour problems and save space. In
applications where space does not allow for two connected elbows, a single
offset can bypass an obstruction. All offsets are supplied with one joint
stack assembly. The overall dimension may not exceed 10 ft. (3.05m).
Sentron Low Amp Busway
Flatwise Offsets, Minimum Leg Dimensions
Ampere Rating| _“A”_ Std./min. _
Inches(mm)| | Ampere Rating| “B”_ Std./min. _
_Inches(mm)
---|---|---|---|---
**Aluminum ****Aluminum
225| 7.0(178)| | 225| 8.5(216)
400| 7.5(191)| | 400| 8.5(216)
600| 8.5(216)| | 600| 8.5(216)
****Copper Copper**
225| 7.0(178)| | 225| 8.5(216)
400| 7.0(178)| | 400| 8.5(216)
600| 7.5(191)| | 600| 8.5(216)
800| 8.5(216)| | 800| 8.5(216)
End Tap Boxes and Center Tap Boxes
Sentron Low Amp Busway
End Tap Boxes
End tap boxes are non-fusible devices used to connect cable and conduit to the
end of a busway run or where busway runs connect without the need for
overcurrent protection. End tap boxes may be installed at the end or
beginning of a run.
Vertical end tap boxes and horizontal end tap boxes can be installed in both
horizontal and vertical applications. One joint stack assembly is provided
with each end tap box.
Center Tap Boxes
Center tap boxes are non-fusible devices utilized to feed to or take off power
from the busway run. When loads served by the busway run do not require
overcurrent protection, center tap boxes may be used. Center tap boxes are an
actual part of the busway run and require a space of 32 in. (810mm) for
installation.
One joint stack assembly is provided with each center tap box.
Horizontal End Tap Boxes, Lugs
Aluminum
225| 1| #6 AWG – 350 kcmil| 1
400| 1| #4 AWG – 600 kcmil| 1
600| 2| #4 AWG – 600 kcmil| 1
Copper
225| 1| #6 AWG – 350 kcmil| 1
400| 1| #4 AWG – 600 kcmil| 1
600| 2| #4 AWG – 600 kcmil| 1
800| 3| #4 AWG – 600 kcmil| 1
225| 1| #6AWG-350kcmil| 1
---|---|---|---
400| 1| #4AWG-600kcmil| 1
600| 2| #4AWG-600kcmil| 1
**Copper**
225| 1| #6AWG-350kcmil| 1
400| 1| #4AWG-600kcmil| 1
600| 2| #4AWG-600kcmil| 1
800| 3| #4AWG-600kcmil| 1
Vertical End Tap Boxes, Lugs
| 225 | 4 | #6AWG-350kcmil | 1 |
|---|---|---|---|
| 400 | 4 | #4AWG-600kcmil | 1 |
| 600 | 4 | #4AWG-600kcmil | 1 |
**Copper**
225| 3| #4AWG-600kcmil| 1
400| 4| #4AWG-600kcmil| 1
600| 4| #4AWG-600kcmil| 1
800| 4| #4AWG-600kcmil| 1
Flanged Ends
Flanged Ends
Flanged ends provide a direct connection to low voltage switchgear,
switchboards, motor control centers, large power panels, and other electrical
distribution equipment.
Flanged ends are shipped with one joint stack assembly. The switchgear
manufacture supplies lugs and mounting hardware.
See illustration for flanged end drilling patterns. A combination flange/elbow
may be used when the busway is in close proximi- ty to the switchgear.
Flatwise and edge- wise combination flange/elbows require a minimum clearance
of 5 in. (127mm) off the top of the switchboard to the centerline of the
busway.
Flanged Ends Bus Bar Drilling Pattern, Dimensions
Ampere Rating| Dimensions Inches(mm)
FigureNo. W
---|---
**Aluminum
225| 1.50 (38)| 0.75(19)| 2
400| 2.80 (71)| 1.40(36)| 2
600| 4.25(108)| 1.25(32)| 2
****Copper**
225| 0.75 (19)| 0.38(97)| 1
400| 1.50 (38)| 0.75(19)| 2
600| 2.80 (71)| 1.40(36)| 2
800| 4.25(108)| 1.25(32)| 2
Expansion Fittings, Reducers and Phase Rotation Fittings
Expansion Fittings
Expansion fittings accommodate for expansion and contraction of a busway run.
In order to compensate for the difference in the coefficient of expansion
between the copper/aluminum bus bars and the aluminum housing, an expansion
fitting must be used. Expansion fittings are installed in the center of long
busway runs, where both ends of the run are held in a permanent, fixed
positions or where a busway run crosses an expansion joint of a building.
Additionally, NEMA recommends the use of expansion fittings when the run
exceeds 200 ft. (608m).
Expansion fittings allow for a +/- 2 in. (50.8mm) movement along the length of
the busway system.
Fused Reducers
The NEC (Art. 364-11) requires overcurrent protection when busway systems are
reduced in ampacity. A fused reducer is used to reduce the allowable ampere
rating in those sections of the busway run that do not require a higher rating
(i.e. at branch circuit junctures).
Non-Fused Reducers Non-fused reducers are used in conjunction with the
following exception to the NEC (Art. 364-11): “For industrial establishments
only, omission of overcurrent protection shall be permitted at points where
busways are reduced in ampacity, provided that the length of the busway having
the small ampacity does not exceed 50 ft. (15.2m) and has an ampacity of at
least equal to one-third the rating or setting of the overcurrent device next
back on the line, and provided that such busway is free from contact with
combustible material.” Special joint stack connections are provided for non-
fused reducer connections. Consult Factory for specific design
guidelines.
Phase-Rotation Fittings
Phase-rotation fittings can be used when the application requires a phase
rotation in the power supply. Phase rotation fittings can be ordered for
“phase and ground”, “phase only” and “ground only” rotations.
Hangers, Supports, End Closures and Flanges
Hangers
A complete selection of hangers is available to support Sentron Low Amp Busway
in both vertical and horizontal applications. The standard picture frame
hanger comes complete with hardware (cat# UJ100) to connect to a ceiling hung
drop rod. The contractor must supply drop rods to complete assemblies for both
picture frame hangers and trapeze hangers. Picture frame and trapeze hangers
are designed to be hung on maxi- mum 10 ft. (3.05m) centers throughout
thebusway run. Additional hangers may be
used if structural requirements mandate their use. Spring hangers and floor
supports must be used in vertical applications to provide secure mounting of
the busway run.
Spring hangers counter the weight of the busway on each floor and also
compensate for minimal building movement and thermal expansion. Maximum
distancebetween
spring hangers or supports may not exceed 16 ft. (4.88m). When ordering 18 ft.
(5.49m) floor to ceiling height assemblies, intermediate supports or hangers
are necessary.
Flanges
Wall, ceiling and floor flanges are available for Sentron Low Amp Busway. When
the busway run passes through a wall, ceiling or floor a flange should be
used. Flanges do
not offer support to the busway, only a means of covering the hole created in
the existing structure. An additional sealant may be required to meet fire
codes and all other
local requirements. No caulking or gasketing is provided with Sentron Low Amp
flanges.
End Closures
End closures safely terminate a busway run and protect the bus bar ends. End
closures may be removed easily in order to extend a busway run. End closures
are shipped
with Glastic insulation pieces; however, joint stacks and inspection covers
are not included. To ensure proper installation, refer to the end closure
installation instruction sheet shipped with end closure.
Lifting Kit
A specially designed lifting kit (cat. no. SLLK) is recommended when
installing Sentron Low Amp Busway. This lifting kit is designed to help
properly install the busway without damaging equipment during the process.
Technical Data
Aluminum|
---|---
225| 1.50 (38)x.094(2.4)| 10.90| 11.10| 2.10| 2.05| 2.45| 2.83| 3.20| 3.56|
3.89| 4.18| 4.25
400| 2.80 (71)x.094(2.4)| 6.46| 6.55| 1.08| 2.06| 2.48| 2.89| 3.29| 3.67|
4.03| 4.35| 4.48
600| 4.25(108)x.125(3.2)| 3.64| 3.68| 0.54| 1.67| 2.03| 2.38| 2.72| 3.05|
3.36| 3.65| 3.78
Copper| | | | | | | | | | | |
225| 0.75 (19)x.094(2.4)| 13.40| 13.50| 1.64| 2.18| 2.67| 3.16| 3.64| 4.11|
4.56| 4.98| 5.22
400| 1.50 (38)x.094(2.4))| 7.09| 7.17| 1.07| 2.18| 2.64| 3.10| 3.54| 3.97|
4.37| 4.74| 4.91
600| 2.80 (71)x.094(2.4)| 3.92| 3.95| 0.49| 1.70| 2.09| 2.47| 2.85| 3.21|
3.56| 3.89| 4.07
800| 4.25(108)x.125(3.2)| 2.11| 2.13| 0.29| 1.26| 1.54| 1.81| 2.08| 2.33|
2.58| 2.81| 2.92
Notes:
-
For plug-in distributed loads, divide voltage drop values by 2.
-
To determine voltage drop line-to-neutral, multiply line-to-line values by 0.577.
-
Actual voltage drop for different lengths and at loadings less than full rated current can be calculated using the formula:
-
For 50 Hz, multiply reactance (X) by 0.85 and resistance values do not change. For 400 Hz, multiply reactance by 3.75 and multiply resistance by 1.4. Calculate new voltage drop: V d= amps load x =√3(Rcos θ + X sin θ) per 100 ft, where cos θ = Power Factor.
-
For metric conversion R, X, Z values “in Ohms per meters Line to Neutral”
R x .0328
X x .0328
Z x .0328 -
For metric conversion
“Line to Line per meter at 25° C ambient in mV/A/m” (V d 32.8) / A Divide V d by 2 for distributed loads.
Ampere Rating| Bus Bar Width Inches(mm)| Bars perPole| Min. Sectional Area GroundBusorEnclosure
UL857Table6.1
| Sectional Area 50% Internal
GroundBar
| Sectional Area Integral (Housing)
Ground
| CurrentCarrying CapacityRatio
Integral/Internal
---|---|---|---|---|---|---
| | | In2| (mm2)| In2| (mm2)| In2| (mm2)|
Aluminum| | | | | | | | |
225| 1.50 (18)| 1| 0.083| (54.0)| 0.084| (54.19)| 2.124| (1370.32)| 11.35
400| 2.80 (71)| 1| –| | 0.156| (100.64)| 2.582| (1665.80)| 7.43
600| 4.25(108)| 1| –| | 0.235| (151.61)| 3.094| (1996.13)| 5.92
Copper| | | | | | | | |
225| 0.75 (19)| 1| 0.052| (34.0)| 0.043| (27.74)| 1.868| (1205.16)| 19.50
400| 1.50 (38)| 1| –| | 0.084| (54.19)| 2.124| (1370.32)| 11.35
600| 2.80 (71)| 1| –| | 0.156| (100.64)| 2.582| (1665.80)| 7.43
800| 4.25(108)| 1| 0.105| (68.0)| 0.235| (151.61)| 3.094| (1996.13)| 5.92
Note: Ground bar thickness = .055 in. (1.4mm)
UL 1479 Fire Rated Installation
Sentron Low Amp is certified in accordance with UL 1479 and offers a two hour
fire rating for gypsum wallboard construction, and a three hour fire rating
for concrete slab or block penetrations. These ratings are achieved using
standard busway installed with SpecSeal ® sealant from Specified Technologies
Inc.
Ampere Rating| Bus Bar Width Inches(mm)| RMS Symmetrical (
6cycle| kA)
1sec.| 3sec.
---|---|---|---|---
Aluminum| | | |
225| 1.50 (38)x.094(2.4)| 30| 6| 4
400| 2.80 (71)x.094(2.4)| 42| 17| 10
600| 4.25(108)x.125(3.2)| 50| 28| 16
Copper| | | |
225| 0.75 (19)x.094(2.4)| 30| 10| 5
400| 1.50 (38)x.094(2.4)| 35| 20| 12
600| 2.80 (71)x.094(2.4)| 42| 32| 18
800| 4.25(108)x.125(3.2)| 65| 42| 24
Sentron Low Amp Busway Specifications
1.0 General
A. Furnish and install a complete low impedance prefabricated busway
distribution system as shown on the plans.
B. Busway shall be volts phase ____ wire with minimum 50% capacity
integral ground. Aluminum housing shall qualify for grounding purposes.
C. The ampere ratings, approximate footage, fitting, plug-in units, etc., are
shown on the plans. The electrical contractor shall be responsible for routing
the busway to coordinate with the other trades. Final field measurements
shall be made by the contractor prior to release of the busway for
fabrication.
2.0 Short-Circuit Rating and Tests
A. The short-circuit rating of the busway shall be (consulting engineer’s
calculated required rating), RMS symmetrical amperes.
B. The short circuit rating of the busway shall be determined according to UL
Standard No. 857 or IEC 439-1 and 439-2. This rating must be based upon
actual tests at the rated short-circuit current forsix (6) cycles.
3.0 Basic Construction
A. Housing
- The busway housing shall be of extruded aluminum painted with polyester urethane powder paint to provide protection against corrosion.
- The busway housing shall be totally enclosed non-ventilated for protection against mechanical damage and dust accumulation.
- The busway shall be certified for
IP 40 Indoor, IP 43 Spray Proof, ___ IP 54 Splash Proof).
B. Joint
-
The busway joint shall be of the onebolt type which utilizes a high strength steel bolt and Belleville washers to maintain proper pressure over a large contact surface area.
-
The bolt shall be torque indicating, fully insulated and at ground potential.
-
The bolt shall be two-headed design to indicate when proper torque has been applied and require only a standard long handle wrench to be properly activated.
B Joint (cont’d) -
Access shall be required to only one side of the busway for tightening joint bolts.
-
It shall be possible to remove any joint connection assembly to allow electrical isolation or physical removal of a busway length without disturbing adjacent busway lengths.
C. Bus Bars
- The bus bars shall be tin plated at all contact surfaces.
- Each bus bar shall be insulated over its entire length with Class B, 130° C electrostatically applied epoxy insulation.
- The temperature rise at any point in the busway shall not exceed 55°C rise above ambient temperature when operating at rated load current.
D. Plug-in Openings
- On plug-in busway there shall be five dead front, hinged cover type plug-in openings on each side of ten-foot lengths.
- All openings shall be usable simultaneously.
- Busway shall be installed so that plugs are side mounted to permit practical use of all ten plug-in openings.
- It shall be possible to inspect the plug-in opening and bus bars prior to the installation of the plug-in unit.
- All plug-in openings should be rated IP2X.
E. Support of Busway
- Hanger spacing shall be noted on layout drawings and should not exceed manufacturers’ recommendations.
- Feeder and plug-in busway shall be approved for hanger spacing of up to 10 ft. for horizontally mounted runs and up to 16 ft. for vertically mounted runs.
F. Underwriters’ Laboratories Listing
- All straight lengths, fittings, and plugin units shall be listed and marked in accordance with UL Standard No. 857 or IEC 439-1 and 439-2.
- This listing shall include mounting of the busway in any position (i.e., horizontal, flatwise, edgewise, and vertical) withoutderating.
4.0 Voltage Drop
A. The voltage drop (input voltage minus output voltage) specified shall be
based on the busway operating at full rated current and at stabilized
operating temperature in 35°C ambient temperature.
B. The three-phase, line-to-line voltage drop shall not exceed 4.2 volts per
hundred feet at 70% power factor concentrated load, which condition may exist
during motor starting.
5.0 Plug-In Units
A. Plug-in units shall be circuit breaker type or fusible switch type
with visible blade, and quick-make / quick-break mechanism.
B. Plug-in units which cannot be operated directly from the floor shall be
equipped with suitable means for hookstick operation.
C. The interrupting rating of circuit breaker plug-in units shall be [ ] RMS
symmetrical amperes.
6.0 Plug-In Unit Safety Devices
A. Each plug-in unit shall be mechanically interlocked with the busway housing
to prevent installation or removal of plug-in units while the switch is in the
ON position.
B. Plug-in enclosures shall make positive ground connection with the ground
bus before the contact fingers make contact with the phase bars.
C. The plug-in units shall be equipped with internal barriers to prevent
accidental contact with live parts on the line side of the protective device
during time of wire pulling.
D. Covers of all plug-in units must have “releasable” type interlocks to
prevent the cover from being opened when the switch is in the ON position.
7.0 Fire Rating
A. The busway shall be UL Listed to meet two-hour fire ratings for gypsum
wallboard construction and three-hour fire rating for poured concrete or
concrete block construction.
8.0 Quality
A. All busway products shall be manufactured in a facility which is Quality
Systems registered to ISO9001.
9.0 Approved Suppliers
A. All major components shall be of the same manufacturer as the busway. The
busway and plug-in units shall be manufactured by Siemens.
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