Electrical Systems Design

beepedblacksmithUrban and Civil

Nov 29, 2013 (3 years and 10 months ago)

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Assumption University
Thailand

EE4503

Electrical Systems Design

Raceways

1

Assumption University
Thailand

Topics


Introduction to Raceways


Conduits


Conduit Installations


Wireways
, Auxiliary Gutters, Cable Trays


Fittings

2

Assumption University
Thailand

Raceways


Damage e.g. physical, chemical


Human Contact


Easy Wiring e.g. wiring, maintenance


Grounding for Metal Conduit


Limit the scope of damage e.g. fire, short
circuit


3

Assumption University
Thailand

Conduits


RMC, IMC, EMT

Catalog of
Panasoics

4

Assumption University
Thailand

Conduits


RMC

Rigid Metal Conduit


Strongest conduit (except concrete :p)


(Usually) Galvanized


Usage: All weather, all terrain


Standard:
1
2



6” (15mm


150mm) and
3m length


5

Assumption University
Thailand

Conduits


IMC

Intermediate Metal Conduit


Thinner than RMC


(Usually) Galvanized


Usage: All weather, all terrain


Standard:
1
2



4” (15mm


100mm)

and
3m in length

6

Assumption University
Thailand

Conduits


EMT

Electrical Metallic Tubing


Thinner than IMC & RMC


Not allow to have thread


Usage: Only in building (not under
ground, not for high voltage)


Standard:
1
2



4” (15mm


100mm) and
3m in length


7

Assumption University
Thailand

Conduits


FMC

http://www.delikon.com/brass.htm

8

Assumption University
Thailand

Conduits


FMC

Flexible Metal Conduit


Metal conduit with the high flexibility


Usage: Vibration or Need Bending


Standard:
1
2



3” (15mm


80mm)


Installation:
Need support every 1.5m and 0.3m
(in case of termination point / junction box)

9

Assumption University
Thailand

Conduits


RNC

Rigid Nonmetallic Conduit


Built from nonmetallic material: e.g. PVC


Disadvantage:
Not as strong as metal and limit
temperature usage


Advantage:
Sustain to erosion, humidity, impact


Usage: Exposed, Conceal, Wet &
Himid

or
underground (usually using “duct bank”)

10

Assumption University
Thailand

Conduits


RNC

Duct Bank

http://www.chana.egat.co.th/newweb/gallery/?level=picture&id=28

http://www.iowaconcrete.com/node/707

11

Assumption University
Thailand

Conduits


Comparison

http://www.mc2
-
ice.com/services/estref/popular_conversion_files/electrical/conduit_weight.html

12

Assumption University
Thailand

Conduits Installation:
RMC, IMC

http://www.mikeholt.com/instructor2/img/product/pdf/1259687476sample.pdf

13

Wet Location:
accessories needed to be specified as

Raintight
” or “Wet locations”

Assumption University
Thailand

Conduits Installation:
RMC, IMC

Electrical Systems Design:
ประสิทธิ์ พิทยพัฒน


14

Cinder Fill:
In corrosive area (e.g. under
permanently moist), required at least 2”
concrete

Assumption University
Thailand

Conduits Installation:
RMC, IMC

http://
www.electrix.co.uk/view_product_options.php?id=1117

http://ecmweb.com/site
-
files/ecmweb.com/files/archive/ecmweb.com/images/112ecmCBfig1.jpg

15

Box:
Where conduit reaching the box, “bushing” is
required to protect the
cable’s

Assumption University
Thailand

Conduits Installation:
RMC, IMC

Electrical Systems Design:
ประสิทธิ์
พิทยพัฒน


http://www.tpub.com/ceb/
71
.htm

16

Bend:
Number of bends in one run should
<=
360
o

Assumption University
Thailand

Conduits
Installation
-

Supports

Electrical Systems Design:
ประสิทธิ์ พิทยพัฒน


http
://www.ci.oceanside.ca.us/civica/filebank/blobdload.asp?BlobID=
22230

17

Assumption University
Thailand

Conduits Installation:
RMC, IMC

Splices and Taps:
only inside the box




18

http://www.diyadvice.com/diy/electrical/fans
-
heat/whole
-
house
-
ventilating
-
fan
/

http://www.familyhandyman.com/DIY
-
Projects/Lighting/Kitchen
-
Lighting/how
-
to
-
install
-
under
-
cabinet
-
lighting
-
in
-
your
-
kitchen/View
-
All

Assumption University
Thailand

Conduits
Installation
-

# of Cables


Need space inside conduit:


Heat Ventilation


Cable’s insulator will not be damaged.

19

http://www.simpullsolutions.com/documents/SIMpullTHHNInstallationandApplicationGuide
8
-
15
-
07
.pdf

Assumption University
Thailand

Conduits
Installation
-

# of Cables

table

20

http://www.telepart.net/
ตารางการติดตั้งสายไฟในท


Wire
-
Conduit
-
Table.html

Assumption University
Thailand

Conduits
Installation
-

# of Cables

calculation

21

Calculate directly from the cable’s outer
diameter (
𝑑
)
and conduit’s inner
diameter
(
𝐷
) and
𝑛

is the number of cables.

%𝐹𝑖𝑙𝑙
=

𝑛

𝜋
𝑑
2
2
𝜋
𝐷
2
2

100
=
𝑛

𝑑
𝐷
2

100


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Thailand

Wireways

22

http://www.indochinaengineering.co.th/product.php?id_product=30

Assumption University
Thailand

Wireways


Raceways are folded from sheet metal.


General usage in open area. If outside
building, specify “
Raintight



Not use when risk of severe physical
damage.


Height: 50, 75, 100, 150, 200 mm


Width: 50, 75, 100, 150, 200, 250, 300 mm

23

Assumption University
Thailand

Wireways


Use current rated for the metal conduit.


Use reduction factor, if >
30
cables.


Need supports for every
1.5
m.


Cannot use through the wall or floor.


Cannot use as grounding cable.


Use no more than
20
% fill.

24

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Thailand

Auxiliary Gutters


Similar to
wireways


Collect the cable before distribute.

25

http://www.contractortalk.com/f
32
/some
-
recent
-
work
-
34277
/

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Thailand

Cable Trays

26

http://
www.indochinaengineering.co.th/product.php?id_product=
32

Assumption University
Thailand

Cable Trays


Cable Tray is not Raceways, but is
commonly used in industry to support
cable.


Cheap and easy to use.


Only for specific cable types, e.g. multi
-
core cables

27

Assumption University
Thailand

Cable Trays


Ladder Type

For heavy
-
duty power distribution

28

http://
www.shreemahalaxmisteel.com/cable
-
trays.html

http
://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf

Assumption University
Thailand

Cable Trays


Perforated Type

For power cables, small cables and control
cables

29

http://
www.shreemahalaxmisteel.com/cable
-
trays.html

http
://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf

Assumption University
Thailand

Cable Trays


Solid Bottom Type

For small cables.

30

http
://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf

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Thailand

Cable Trays


Comparison

http://www.cooperindustries.com/content/dam/public/bline/Resources/Library/catalogs/cable_tray_systems/all_products/CTManual.
pdf

31

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Thailand

Fittings


Accessories to be used with race way.


Purpose


To firmly hang the raceway


To smoothly change the direction of raceway


To easily pull the cable into the raceway


To properly splice the cables

32

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Thailand

Fittings
-

Boxes

33


Termination point (switch, receptacle) or
Stop point (splice, tap) for the wiring
system.


Metal or non
-
metal.


Sizing is based on the required space.


Have no hole for the object larger than 7.5
mm in diameter to pass thru.

Assumption University
Thailand

Fittings
-

Boxes

http://www.topaz
-
usa.com/catalogs/electrical_fittings_catalog.pdf

34

Assumption University
Thailand

Fittings


Pull Boxes

http://ecmweb.com/code
-
basics/sizing
-
junction
-
boxes

35

Assumption University
Thailand

Fittings


Pull Boxes

straight pulls

http://ecmweb.com/code
-
basics/sizing
-
junction
-
boxes

36

The horizontal
dimension (A)
is
8
times of the
largest raceway
size.

Assumption University
Thailand

Fittings


Pull Boxes

angle pulls

http://ecmweb.com/code
-
basics/sizing
-
junction
-
boxes

37

The distance between
raceways (C) is 6 times
of the diameters of the
raceways.

Assumption University
Thailand

Fittings


Other Accessories

Connectors

http://
www.topaz
-
usa.com/catalogs/electrical_fittings_catalog.pdf

http://numthaveerung.co.th/pdf/Steel%20Conduit
-
Accessories%20Fitting.pdf

38


Steel Coupling


Compression


Set Screw


Rain Tight

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Thailand

Fittings


Other Accessories

Bushing

http://
www.topaz
-
usa.com/catalogs/electrical_fittings_catalog.pdf

39


Metal


Non
-
metal


Grouding

Assumption University
Thailand

Fittings


Other Accessories

Elbow & Strap

http://
www.topaz
-
usa.com/catalogs/electrical_fittings_catalog.pdf

40


Elbow


Strap

Assumption University
Thailand


Electrical Systems Design:
ประสิทธิ์ พิทยพัฒน



Reference

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