AAAC Conductor Technical Specification

AAAC (All Aluminium Alloy Conductor) is widely used in overhead electrical distribution systems.

This post explains AAAC conductor equivalent to ACSR Dog conductor, its specifications, properties, testing, packing, applications and its standards.

Scope

This specification provides for the manufacturing, testing before dispatch, supply and delivery of all aluminium alloy stranded conductors for use on 33/11 KV and L.T. overhead lines in the Electricity Distribution System as per details.

Conductor Size

7/4.26 mm (100 mm² nominal Aluminium area) = Equivalent to ACSR Dog.

Standards

The conductor shall conform to the following Indian Standard (IS) Specifications which shall mean latest revisions with amendments/charges adopted & published unless specifically stated otherwise in the specification:

1). IS: 398(Part-IV) 1994: Specification for aluminium conductors

2). IS: 1778-1980: Specification for Reels and Drums for bare conductors.

Material and Workmanship

Material Quality

Material used in manufacturing of the conductor may be of the highest quality of its type obtainable & except where modified by the specification that shall comply in all respects with the standards that is laid down by Indian Standard (IS) Institution.

Conductor Composition

The conductor shall be manufactured at hot-treated aluminium-magnesium-silicon (Al-Mg-Si) alloy wires containing approximately 0.5% magnesium and approximately 0.5% silicon (Si) and having electrical and mechanical properties as contained in IS: 398(Part-IV) 1994.

Wire Quality

All the wires (strands) shall be reasonably smooth and uniform that shall be free from all defects such as die-marks, scratches, abrasions and kinks etc. after drawing & also after stranding.

Finished Conductor Requirements

The wires shall be smooth and free from all imperfections such as spills, splits, etc. 

The finished conductor shall have a smooth surface without any surface dent, abrasions, scuff marks and shall be free from dirt, grit etc. 

Also the conductors that is finished shall be free from loose strands. 

The conductor ends shall be properly get sealed to avoid unwinding of the strands.

Handling & Transportation

Particular care has to be taken by the supplier/manufacturer during the manufacture, handling, packing & transportation of the conductor to see that the surface is not dented, cut (or) damaged in any way.

Properties of Conductor

The properties of stranded aluminium (Al) alloy conductors shall be as in the table below:

Nominal Al Area (MM²)	Stranding & Wire Dia (MM)	Sectional Area (MM²)	Overall Dia (MM)	Mass (Kg/Km)	Resistance (Ohm/Km) @ 20°C	Breaking Load (KN)
100	7/4.26	100	12.78	272.86	0.3390	29.26

Properties of Wires

The properties of aluminium alloy wire to be used in the manufacture of the stranded conductor shall be as in the table below:

Diameter Nom. (mm)	Min. (mm)	Max. (mm)	Cross Section (mm²)	Mass (Kg/Km)	Breaking Load Before (KN)	Breaking Load After (KN)	Resistance @ 20°C (Ohm/Km)
4.26	4.22	4.30	14.25	38.48	4.40	4.18	2.345

Modulus of Elasticity & Coefficient of Linear Expansion

The Modulus of elasticity shall be as per IS: 398 (Part-IV) 1994 and amendments thereof. 

The values of the coefficient of linear expansion for AAAC shall be 23.0×10⁻⁶.

Joints

Conductor containing 7 Wires

No Joints Requirement

There shall be no joints of any kind in any wire of a stranded conductor containing 7 wires except those made in base rod (or) wire before final drawing.

Certification

A certificate shall be recorded by the supplier on each & every invoice/bill and challan as follows:

“Certified that there are no joints of any kind in any wire of the conductor.”

Stranding

The wires used in manufacture of the stranded conductor before stranding shall conform to all the relevant requirements of IS: 398 (Part-IV) 1994. 

The wires shall be evenly and closely stranded.

Lay Ratio of Conductor

The lay ratio (ratio of the axial length of a complete (full) turn of the helix formed by an individual wire in a stranded conductor to the external diameter of helix) shall be within the limits as given below:

For AAAC Dog Conductor: Minimum 10 and Maximum 14.

Tests

The wires used for alloy conductors shall comply with the following tests as per IS: 398 (Part-IV) 1994 and/or as specified by the purchaser.

All the tests given below shall also be carried out by the representative of the purchaser and samples by cutting 1-2 meters from the outer end of the finished conductor from not less than 10% of the finished reels (or) drums (except of Test no. 6)

Test-1: Check for diameter of individual Aluminium Strands.

Test-2: Check for lay ratio of various layers of Aluminium Alloy wires.

Test-3: Breaking load tests on individual Aluminium Strands.

Test-4: Elongation tests.

Test-5: Electrical resistance test on each strand.

Test-6: Checking of conductor surface that is declared length and its weight.

Test-7: Visual inspection test on the conductor drums as per IS: 1778/1980.

Test-8: The rejection & retest procedure shall be followed as stipulated in IS: 398 (Part-IV) 1994

Test and Test Certificate

The conductor shall be subjected to all tests laid down in the relevant Indian Standards at contractor’s works or at approved test laboratory at contractor’s cost. 

Certified copies of test certificates in respect of tensile tests of Aluminium and electrolytic quality of Aluminium and all other tests as prescribed in the relevant Indian Standards (IS) shall be furnished by the contractor.

Calibration of Testing Equipments

1. Tensile Testing Machine and 
2. Kelvin’s Bridge machine etc. 

shall be checked from the competent authority for calibration once in a year. 

Calibration certificates when demanded by the inspecting officer shall be produced for verification purposes. 

In case of dispute regarding calibration the instruments shall be jointly sealed and sent to a testing lab of repute for calibration at the cost of the supplier.

The result of such checking shall be binding on the supplier.

Packing & Marking

Drum Specifications

The conductors shall be supplied on strong non-returnable wooden drums so that it is not damaged during transit and can withstand all the transit and weather hazards. 

The conductor drums may confirm to IS: 1778/1980. The drums shall be strapped with steel wire.

Each drum must have the following information marked on it with indelible ink along with other essential data:

1. Organization name

2. Designation of Consignee

3. Drum number of the conductor

4. Specification number

5. Size and type of conductor

6. Number and length of each conductor in the drum

7. Gross weight of the drum

8. Weight of the empty drum

9. Net weight of conductor

10. Position of conductor end

11. ISI mark

Maximum Packing Weight

The gross weight of each packing in case of AAAC conductor shall not exceed by > 10% of the values given in the following table:

Conductor Size	Gross Mass (Kgs)
100 mm² Aluminium Area (7/4.26 mm)	1500

Length & Variations in Lengths

The standard length for all AAAC conductors shall be as given below. 

Non-standard lengths shall not exceed more than 10% of the ordered quantity.

Conductor	Standard Length	Non-Standard Length
AAAC Conductor	1.00 KM	0.75 KM

Tolerance Of Quantities

The total permissible variation for the entire quantity ordered shall be subjected to a limit of ±1% (one percent) for orders upto 500 KM and ±½% (half percent) for orders above 500 KM. 

However, the permissible variation in case of individual consignee may be ±5%.

Applications

Used in 33 kV, 11 kV and LT overhead distribution lines, substations and power distribution networks.

Conclusion

AAAC (AL-59) equivalent to ACSR Dog conductor provides reliable performance for power distribution systems.