Estimating and Costing of materials required for House Wiring or residential plan

Estimating and Costing of materials required for House Wiring or residential plan


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Hello everyone, in this article I will discuss the estimation and cost of the lighting circuit and heating circuit for house wiring or residential plan.

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Given data: Consider the given residential plan.


This is the plan where we should calculate everything i.e., what are the materials required for the plan and make a chat of materials with costing.


All dimensions are in a meter

The following assumptions are made :


  •  The height of the meter board, distribution board from the floor level = 2 meters.
  •  Height of horizontal run and lighting fitting from floor level = 3 meters.
  •  Height of switchboard from floor level = 1.5 meters.

Step-01



Total lighting load and number of circuits

SI.NO
Location
Area(meter square)
Wattage
(10W/m sq)
     No
  of
points
Types of fitting
lights
fans
socket
01
Verandah
8
80
1×60
-
-
Pendent
02
Room
12
120
1×40(FL)
1×80
1×60
Pendent
1×60(IL)
batten
03
Hall
16
160
2×40
1×80
1×60
Pendent
1×60
& batten
04
Kitchen
9
90
1×40
-
PS=2000
Pendent
1×60
& batten
05
Passage
1.5
15
1×60
-
PS=1000
Pendent
06
Bath roon
2.5
2.5
1×60
-
Pendent
Total load =
480w
160w
120w

Total lighting circuit load = 480 + 160 + 120 = 760 watts


Total heating circuit load = 3000 watts

Total load of Installation = 760 + 3000 = 3760 watts

No of the lighting circuit
                   = Total lighting circuit load/800
                   =  760/800 = 0.95

If the total lighting circuit load exceeds 800 watts then two circuits must be provided, but here total lighting circuit load is less than 800 watts.

Therefore, only one circuit is used.

Hence from the Meter board, one lighting and one heating circuit are taken.

Step-02


Wiring diagram for the given plan:
MB - Meter Board
DB - Distribution Board
SB - Switch Board contains switches & sockets

Step-03 :


Size of the wire

To calculate any size of the wire, first we should calculate load current and by using a wire table size of the wire can be calculated.

Load current = Total lighting circuit load/Voltage 
                      = 760/230 = 3.30 Amps
let, a factor of safety be 2(for future demands or load)

Current rating = load current * 2 
                        = 3.30 * 2 = 6.6 Amps

Therefore, for lighting circuit 3/22 SWG copper wire is selected from the wire table

Step-04:


Length of Conduit required, use concealed conduit system of wiring.

SI.NO
Location
Horizontal run
Vertical drop to switch
Vertical rise pipe line to ceiling fan
Wall crossing
Total
01
Verandah
4+2
-
0.5
6.5
02
Room
3+2
1
0.5
6.5
03
Kitchen
3+1.5
1
0.5
6
04
Hall
4+4+4
1
0.5
0.33 * 5 = 1.65 (overall)
12
05
Passage
1+1.5+0.75
1
0.5
3.25
06
Bath
1.25
1
0.5
2.75
Total
1.65
37

Total = 37 + 1,65( wall crossing )
         = 38.65 = 39 (say)

Total PVC conduit = 39 +5% wastage
                              = 40.95 = 41 meter  (say)

Step-05:


The total length of wire required

length of wire(3/22 copper wire) = 41 * 3 
                                                     = 123 meter

Step-06:


Wood screws(assorted size) = 4(No of MB+SB)
                                             = 4(1 + 4)
                                             = 20 + 5% wastage
                                             = 21.95 Nos

Step-07:


The number of wood plugs required is  22 Nos as same as wood screws.

Step-08:



Other accessories required

01. ICDP Switch 

load current = 3.30 * 2 = 6.6 Amps
A 15A ICDP switch is selected or 15A MCB is used.

02. Switches = No of lamps + fans + sockets
                     = 12 + 2
                     = 14 Nos
A 250 V, 5 A switches = 14Nos

03. A 250 volts, 5 A, 3-Pin socket = 2 Nos
04. No of fan regulators = 2 Nos 
05. No of Pendant holder = 6 Nos
06. No of Angle holder = 4 Nos
07. No of ceiling roses = No of fan + No of pendant 
                                      = 2 + 6 = 8 Nos
08. Fluorescent fitting, 230 V, 5 A = 4 set
09. Ceiling fans, 230 V = 2 set
10. Incandescent fitting = 6 set
11. No of Tees = 4 Nos
12. Meter Board = 1 Nos
13. Switch Board = 4 Nos

Step-09:


Labor Charge

The labor charge depends upon the number of points

No of point 
           = (lights + fan + sockets) * 0.5 + MB + DB
           = (10 + 2 + 2) * 0.5 + 1 + 1
           = 15 Nos

Labor Cost = Cost per point * No of points
                   = 195 * 15 = Rs 2970.00

Step-10:


Cost of Materials


01. For heating load



load current = Total heating circuit load / Voltage
                    = 3000 / 230 = 13.04 Amps

Current rating = load current * Factor of safety
                       = 13.04 * 2 = 26.08 Amps

Therefore, 7/20 SWG copper wire is selected.

02. PVC Conduit required 


Horizontal run = 4+2+4+1+2.5+1.5+3
                        = 18 meter
Vertical drop = 1+1 = 2 meter
Wall crossing = 0.33 * 4 = 1.32 meter
Total PVC Conduit = 21.32 = 22 (25mm, 2mm thick)

Therefore, Total PVC conduit = 22 + 10% wastage
                                                 = 24.2 = 25 meter

03. Length of wire required


Length of wire = 3 * length of PVC conduit
                         = 3 * 25
                         = 75 meter

04. Wood screws (assorted size) = 4 * 2 

                                                    = 8 No + 5%
                                                    = 8.4 = 9 No's

05. Wood Plugs = 9 No's


06. Other accessories required



(a) ICDP Switch
      Load current = 13.04, FOS = 3
      Current rating = 13.04 * 3 = 39.13 Amps
      A 250 V, 50 Amps selected

(b) Switches - A 250 V, 15 A switches = 2 No's
(c) 3-Pin socket = 2 No's
(d) No of elbows = 2 No's
(e) Switch board (200*250*45 mm) = 2 No's

07. Labor Cost


No of point = 2
labor cost = 195 * 2 = 390

I hope this may help you......                       

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