Procedures For Drawing Approval

1. The procedures to be followed by the consumer in complying with regulations and required technical standards for commissioning the installation are covered in this chapter.

2. The following stages of compliances are involved in the commissioning of an electrical installation

  • Obtaining Load Sanction from the TANGEDCO.
  • Obtaining No objection certificate from the TANGEDCO, if the proposal involves paralleling of Generator set(s) with TANGEDCO’S grid.
  • Obtaining Electrical Inspectorate’s approval for the drawing proposal
  • Erection and Completion of the Electrical Works based on the drawings approved by the Electrical Inspectorate.
  • Supplier's load sanction letter.
  • Submission of Completion Report for works completed.
  • Rectification of defects pointed out after inspection and submission of Rectification Report
  • Commissioning and Reporting.
  • Additions and Alterations to the existing installations.

3. Stages Of Compliance Involved At Electrical Inspectorate.

3.1. approval of drawing.

The following drawings are required to be sent to the electrical Inspectorate for approval:

  • Site plan.
  • Point of Supply and Sub-Station Layout.
  • Schematic Layout.
  • Physical Layout.
  • Generator Layout.
  • OH Lines Layout.

3.1.1. Site plan.

A site plan showing clearly the following:

  • Topo plan showing the geographic location of installation with reference to the roads, village/town and land mark.
  • Boundary of the property with SF numbers, public road, canals or entities other than the consumer, if any ,within the boundary.
  • Location of the supplier’s point of supply,viz; Location of supplier’s structure/ RMG room along with the route of supplier’s HT incoming OH lines /HT incoming cable.
  • Location of consumer’s structure/HT gears near the point of supply, Transformer, Generator and main panel room.
  • The route of the HT OH lines, if any, passing inside and adjoining the premises.
  • Location of various buildings, Halls, Sections etc.
  • Internal roads, clearance between the Transformer and its secondary control gear.
  • In the case of multistoried building of more than 15 Meter height, planning permit letter and building elevation drawings approved by the competent Local planning Authority should be sent along with the drawing proposal showing the set back clearance, drive way clearance and clearance between the buildings in conformity with the drawings approved by the planning Authority.

3.1.2. Point of supply and Sub-station Layout.

  • In case of Outdoor Substation, the following details should be furnished in the drawings.
    • Fencing around consumer’s and supplier’s structure with the location of entrance and the distance between the supplier’s pole and the segregating fence provided for the supplier’s installation from the consumer’s installation.
    • Type and size of poles, pole to pole distance, arrangement of jumpers, AB switch, H.G. fuse, /D.O. fuse. Lightning arresters, supporting channels, jumpers, HT cables, phase to phase clearance, safe working clearance, all round clearance of the Transformers, position of transformer, location and the size of earth leads, oil soak pit and its distance from the substation etc.
    • Distance from the Transformer to the primary and secondary controls.
  • Soil resistivity test report, fault level calculation, data and calculation for step and touch potential at the SS yard in the case of Power plant and EHV sub station, protection against lighting, adequacy calculation for the neutral earthing of the transformers, provision of high velocity water jet, nitrogen injection system for the fire protection of transformer should be forwarded.
  • In case of Indoor sub-station, the following details should be furnished in the drawings:
    • Location of supplier’s RMG unit with the all round clearance provided for the RMG unit and size of HT cables.
    • Cross-sectional views of the substation building indicating the arrangement of transformer, segregating walls between transformers, distance between the transformers and switch gears, type of roofing, plan, section and elevation of bus duct and its support, ventilation, oil soak pit and its distance from substation etc. with all round clearances.
    • Entrance and exit ways of main panel room, location of main panel and any other switch boards at the main panel room with all round clearances.
    • Details of earthing and cable laying arrangement.

3.1.5. Generator Layout

  • Location of the Generators, control panels with all round clearances.
  • Plan and section view of the Generator room.
  • Clearance between Generator and its control panel.
  • Arrangement of exhaust pipe, bus duct and details of earthing arrangement.

3.1.6. O.H. Lines

  • Method of construction of the O.H. line, its size and type of conductor material, wih the details of supporting poles, span length, ground clearances, clearance between phases, guarding arrangements, control / protection provided etc., along with the calculation for factor of safety of the supports.

3.1.7. General Observations

  • The drawings furnishing all the required details should be clear and legible by proper font size.
  • All the drawings should be as far as possible of the same size, uniformly folded to be easily spread-out for scrutiny. They should not be big and unwieldy. Various equipments should be proportionate though not to scale.
  • All the drawings should be given numbers and proper headings.
  • All relevant information relating to equipments / installation / erection should be given under a suitable note/table/reference in each drawing.
  • The connected load on each S.B. and D.B. should be indicated near each board.
  • In the lighting distribution, maximum number of points and connected load to each single phase final sub-circuit should be mentioned.
  • Anything that cannot be explained by symbols and lines should be clarified with neatly lettered notes or explained as a write up.

3.1.8 Documents to be submitted along with drawings

  • An authorisation letter obtained from the consumer authorising the contractor to correspond with the Electrical Inspectorate.
  • The drawings should be signed by both the consumer and the Electrical Contractor who is doing the work.
  • Check list and Questionnaires for drawing approval should be duly filled-up and signed. Model forms furnished below should be used.

Check List (to avoid rejection at the submission level itself)

Sl. No. Item Enclosed by the Consumer / Contractor (Tick Yes or No)
1 Original Chalan for drawing scrutiny fee Yes/No
2 (i) Covering letter of the consumer Yes/No
(ii) Consent letter of the contractor Yes/No
3 Duly filled in questionnaire forms attested by consumer and contractor Yes/No
4 Name of consumer’s authorised signature and the authorisation letter for the authorised signatory. Yes/No
5 4 sets of drawing duly signed by the consumer / contractor Yes/No
6 When the building comes under the category of MSB (exceeding 15m in height) Yes/No
    CMDA / DTCP building planning permit letter / approval drawing (showing the Elevation and site Plan. Yes/No
  Elevation view when the building is having G + 3 floor. Yes/No
7 Topo plan of the site (Showing survey number, boundary line of the site, near by public road adjacent site details etc.) Yes/No
8   Soil resistivity test, fault level calculation, adequacy calculation for earthing the neutral of the transformers. Calculation for step and touch potential at EHV yard, calculation for protection against lighting, short circuit calculation for buses of rating 33 kV and above. Yes/No
  The drawings showing the plan and sectional views of transformers, generators, SS yard, HV & MV panel rooms, provision of high velocity water jet at SS yard in respect of consumers availing EHV supply. Yes/No
9 Provision of HV breaker at the point of supply as per Regulation 37. Yes/No
10 Whether the transformer erected inside the Multi Storied Building is dry type transformer. Yes/No
11 Whether the Diesel Generator is located at Ground floor or first basement. Yes/No
Signature of the Consumer (Name) Signature of the Consumer (Name)

Questionnaire for Drawing Approval

1 (a) Name of consumer with Official Address to which all communications should be addressed  
2 (b) Phone No. and Email of the consumer  
3 Location of HV Installation (Full particulars of the Taluk, Town, village and name of street to be furnished).  
4 Power requirement with Nature of load  
5 Sanction of load with authority (Copy of the TANGEDCO letter)  
6 Name and address of Contractor (with License details) carrying out the installation and the Electrical Supervisor name with competency certificate No. who is directly supervising the work.  
7 Are all equipments and lines of the consumer proposed to be erected entirely within the property of consumer?  
8 Are all the materials and apparatus conform to the relevant specifications and ISI?  
9 Name, Residential address, telephone number of Chairman / MD /Authorised signatory  
10 Copy of memorandum and articles of association of the company  
11 Brief details of proposal  
12 Technical:  
  Details of HV/EHV Installation  
  a. Substation (indoor/outdoor)  
b. Transformer  
c. H.V. Switchgear  
d. H.V. Alternatorr  
e. H.V. Motor  
f. H.V. Capacitor  
g. Other H.V. Equipments  
h. Switch gears Details of normal and rupturing capacity should be furnished  
13 Details of M.V. Installation  
  a. Alternator  
b. Motor and other equipment  
c. Switchgear  
14 Do all the equipment satisfy condition of the Supplier?  
15 Distribution Mains if any (Details of Line Supports and conductor size to be furnished).  
16 Are these to be Erected Entirely within the property of the consumer  
17 Drawing (in Quadruplicate, Signed by the consumer and contractor) to be sent.  
  a. Site Plan showing Point of supply, H.T. Installation routes of Mains (O.H. & U.G) & Topo Plan  
b. Plan and elevation of Substation with clearance to nearby buildings or structures.  
c. Schematic layout of the Equipment  
d. Sectional elevation of switch gears with erection details  
e. Earthing Arrangements  
f. If the Building height is 15m and above, details of Planning permit and drawing approval obtained from the DTCP/CMDA authorities  
g. If the Installation is having building of G +3 floor and above, elevation drawing indicating the total height of the building  
  Whether Chalan for Adequate drawing scrutiny fee as per G.O. 30 is enclosed.  
18 General  
19 Have the Equipment been ordered? If received details, if not received, the probable date of receipt.  
20 Probable Date of Completion of Installation  
21 i. Date of last R45 Inspection ad copy of the defect report.  
ii. Date of last R32 Inspection ad copy of the defect report.  
iii. Compliance of returns on Electricity Tax remittance for consumption on self generation as well as sale of energy  
iv. Compliance of energy data filing in the case of designated consumers under the Energy Conservation Act, 2001.  
Signature of the Consumer Signature of the Consumer