Electrical Supply Lect 6

8/18/2019 Electrical Supply Lect 6

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Unit - 3

BUILDING SERVICES – I

Lecture - 6


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• Electricity is supplied through “wires”, comparableto pressured water supply pipes.

• At points along the wires are lighting outlets,switches, and receptacles. Turning on a light switchor plugging equipment into a receptacle is

comparable to opening a faucet/valve.

Electrical Supply

Electrical su

pply

Can be

compared to

Water supply


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ltage

Equivalent to water pressure; pump controls waterpressure; generator or battery controls voltage;standard voltage is 120/240; most common lowvoltage is 12V


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Amperage

Electrical current; equivalent to low o water !gal/sec"


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Resistance# $pposition to low o current; amount o resistance aected by#

• aterial

• !iameter

• "ength


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%attage

&nit o power; rate at w'ic' a deviceconverts current to anot'er orm !'eator motor"

!Voltage ( Amperage"


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Watt-hour# $nit of energy% measures amount ofenergy/electricity used in one hour

Watts x hours of use=watthours orKWHR, e.g.,

100 w x 24hrs = 2400 whrs/day

= 2.4 KWHRs

2.4 KWHR/day x 0 days/!o.

= "2.4 KWHR/!o

"2.4 KWHR x Rs. #/KWHR = Rs.

$%1/!o


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)irect *urrent

)irect current# *urrent lows in onedirection


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Alternating *urrent

Alternating current# *urrent lows insingle direction but reverses direction atregular intervals


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Electrical )istributionand +ome %iring

E"E&T'(&( T)

*E+E'AT(+

E"E&T'(&(T) T'A+-'TAT(+

E"E&T'(&(T)!(-T'($T(+


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&er'i(e(o))e(tio)s

012/3024,56wire

system


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!istribution anel/&ircuitrea7er o8


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!istribution anel And &ircuits

220-240

*

11%-120*


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le(tri(al itti)gs )d pplia)(es


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%iring


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*onductors

%ire over w'ic' electrons are transmitted


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*opper %ire#,elation between )iameters andAmperage and ,esistance


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-nsulators

+olds electrical current in proper pat'.


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ains


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rounding

or electrical saety. it is required t'at every circuit begrounded 'is assures t'at all metal parts o a circuit t'ata person mig't accidentally touc' are maintained at 3erovoltage. because t'ey are connected directly to t'e ground

'e grounding wire is attac'ed to t'e t'ird slot on a wall

receptacle


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rounded towater pipe or

ground rod


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If hot wire touches cover plate of ungrounded switch or outlet, theplate will be electrically charged. If the body touches the plate, the

body becomes part of the circuit and will receive a shock.


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rounding toreduce s'oc

'a3ard


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Electrical Supply Lect 6

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Transcript of Electrical Supply Lect 6