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I would like to know how to measure(take off) a cable from an electrical drawing, as part of Electrical Quantity survey or Estimation. Please explain me the ways but not using any other software with the exception of Autocad.
Hi,
Initial review of the given drawing and identifying the following:
- Number of out let points
-Types of cable required at each outlet point
-Additional looping requirement if any.
Now calculation of the cable length can be done in two simple method,
The first approach works well when you have few cable runs and it is easy to determine the length of each of them.
The second, averaging approach is used when there are many outlets and it is very time-consuming to determine the length of each of them.
Use the following estimation procedure for every cable type in your house to calculate the Total Cable Length:
Identify the SHORTEST cable run (A) to the outlets closest from the Distribution Device
Identify the LONGEST cable run (B) to the outlet farthest from the Distribution Device
Calculate the AVERAGE cable length (AL)
(AL) = (A + B)/2
Add SLACK (S) of minimum 0.9 m (36 in) at the Distribution Device plus a minimum of 0.2 mm (8 in) of excess cable at the outlet
(S) = 0.9 m (36 in) + 0.2 m (8 in) = 1.1 m (44 in)
Determine the Drop Length (D) at the outlets (if cable runs vertically along the studs to the outlets). For safety, assume Drop Length is equal 4.5 m (15 ft)
(D) = 4.5 m (15 ft)
Calculate the Total Average Cable Length (TACL)
(TACL) = AL + S + D
Calculate the Total Cable Length (TCL) by multiplying the Total Average Cable Length (TACL) by the number of outlets (N)
(TCL) = (TACL) * N
