Estimation And Costing Of House Wiring, Materials Required

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

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Also read – Electrical Estimation And Costing Questions And Answers.

Estimation And Costing Of House Wiring

Given data: Consider a 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)	Points	Points	Points	Type 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 room	2.5	2.5	1*60	–	–	Pendent
			Total load =	480 watts	160 watts	120 watts

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

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

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

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

Cost depends on you which company product you are buying.

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 rupees.

I hope this article may help you all a lot. Thank you for reading. If you have any doubts related to this article “estimation and costing of house wiring” then comment below.

Tags: Estimation And Costing Of House Wiring Or Residential Plan, Materials Required.

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Chetan Shidling

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