{"id":4434,"date":"2026-09-27T19:22:18","date_gmt":"2026-09-27T19:22:18","guid":{"rendered":"https:\/\/huyuglobal.com\/?p=4434"},"modified":"2026-09-27T19:22:20","modified_gmt":"2026-09-27T19:22:20","slug":"for-electric-power-transmission-copper-or-aluminium-wire-is-used","status":"publish","type":"post","link":"https:\/\/huyuglobal.com\/ru\/blog\/for-electric-power-transmission-copper-or-aluminium-wire-is-used\/","title":{"rendered":"\u0414\u043b\u044f \u043f\u0435\u0440\u0435\u0434\u0430\u0447\u0438 \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u044d\u043d\u0435\u0440\u0433\u0438\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u0442\u0441\u044f \u043c\u0435\u0434\u043d\u044b\u0439 \u0438\u043b\u0438 \u0430\u043b\u044e\u043c\u0438\u043d\u0438\u0435\u0432\u044b\u0439 \u043f\u0440\u043e\u0432\u043e\u0434?"},"content":{"rendered":"

When you glance at a power line, most probably it is made of aluminum, although in laboratory copper is a better conductor. The determining factor for the use of aluminum is not electricity but the weight, the extent of the spans and the price. This article outlines the uses of each material, explains why aluminium has already prevailed over copper in the case of overhead transmission lines but still competes with it in underground transmission and switchgears and describes what it leads to at the termination points of the line.<\/p>\n

Short answer: The greatest amount of overhead electrical power transmission is conducted through aluminium wires, as it accounts for over 90% of imported power transmission wires. Aluminium wires used for electrical power transmission are commonly known as ACSR, which refers to steel cored aluminium wire. Copper wires are used in cases where space and reliability of connections must be preferred to wire weight, such as cable installation, buses, motors and transformers. Aluminium transmits only 61% as much electricity as copper and its cost is about 25-30% of the copper cost, yet it weighs 70% less than copper and means that an aluminium wire with the same resistivity as copper weighs approximately twice less because it has the same electric resistance with copper wire and is somewhat larger in diameter.<\/p><\/blockquote>\n

The numbers that settle the argument<\/h2>\n

The two metals excel at conducting electricity, but the difference is much less than most people think when we are not comparing wires of the same size but wires of equal capacity. Copper is a winner because it is more volumetric; copper can carry more electricity for a wire of same area. Aluminium is a winner thanks to its specific weight; it is significantly lighter and much cheaper for the same conductance.<\/p>\n\n\n\n\n\n\n\n\n\n
Property at 20 \u00b0C<\/th>\nHard-drawn copper<\/th>\nHard-drawn aluminium<\/th>\nGalvanised steel<\/th>\n<\/tr>\n
Resistivity (\u00d710-8<\/sup> \u03a9\u00b7m)<\/td>\n1.72<\/td>\n2.83<\/td>\napprox. 14<\/td>\n<\/tr>\n
Conductivity (% IACS)<\/td>\n97 (annealed copper 100)<\/td>\n61<\/td>\napprox. 12<\/td>\n<\/tr>\n
Density (kg\/m\u00b3)<\/td>\n8,890<\/td>\n2,703<\/td>\n7,800<\/td>\n<\/tr>\n
Ultimate tensile strength (MPa)<\/td>\n380-420<\/td>\n160-200<\/td>\n1,300-1,500<\/td>\n<\/tr>\n
Temperature coefficient (\u00d710-3<\/sup>\/\u00b0C)<\/td>\n3.93<\/td>\n4.03<\/td>\n4.5<\/td>\n<\/tr>\n
Relative material cost (2026 indicative)<\/td>\nUSD 8,800-11,000 per tonne<\/td>\nUSD 2,400-3,200 per tonne<\/td>\nApplication-dependent<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

In terms of engineering, the implications become clear. When it comes to electrical resistance, aluminium has approximately 1.6 times more surface area than copper, which is approximately 1.28 times wider than copper. However, despite the size of this conductor, it has only about half as much weight. In addition, since prices of raw materials for production of aluminium are significantly lower than copper, an aluminium conductor of the same size costs approximately 35-50% of its copper counterpart and is also 52% lighter by itself.<\/p>\n

Whereas aluminium has a major downside in mechanical terms. Its strength in tensile terms is almost half lower than that of copper. In addition, it has disadvantages when under long-term load when it suffers from elongation.<\/p>\n

\"The<\/p>\n

Why aluminium won the overhead line<\/h2>\n

By splitting the two responsibilities, the problem disappears completely. ACSR (Aluminium Conductor Steel Reinforced) consists of aluminium wires outside and a steel and galvanized steel core inside. The steel core maintains the tension while aluminium is responsible for carrying the current. The steel plays almost no role from the electrical point of view since it is located at the core of the conductor, with its current density being the lowest in this type of conductor. The conductor is designated as 54\/7, which means that there are 54 aluminium wires around the 7 strands of the steel core.<\/p>\n

When the conductor is made light, the construction of the entire transmission system is made cheaper. Lighter wires allow for longer spans between the pylons, which means fewer pylons, smaller foundations, and less land being cleared. According to various industry estimates, the savings for infrastructure when all-copper systems are used can be as high as 20-40%. In longer lines, this advantage surpasses all calculations of efficiency of conductivity.<\/p>\n

There is another bonus to be taken into consideration. Since the design of equal-resistance AC conductors is about 28% wider in the diameter, the electric charge is distributed on the surface more evenly and the effect of corona discharge is lessened. What seems to be an excess in size at the construction site makes a good bonus at the voltage level of 400 kV.<\/p>\n\n\n\n\n\n\n\n\n
\u041f\u0440\u043e\u0432\u043e\u0434\u043d\u0438\u043a<\/th>\n\u041a\u043e\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044f<\/th>\nStrength source<\/th>\n\u0413\u0434\u0435 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u0442\u0441\u044f<\/th>\n<\/tr>\n
AAC<\/td>\nAll-aluminium strands<\/td>\nAluminium only<\/td>\nShort spans, substation bus, urban distribution<\/td>\n<\/tr>\n
AAAC<\/td>\nAluminium-magnesium-silicon alloy strands<\/td>\nAlloy<\/td>\nCoastal and industrial atmospheres; no bimetallic corrosion<\/td>\n<\/tr>\n
ACSR<\/td>\nAluminium over galvanised steel core<\/td>\nSteel core<\/td>\nThe default for overhead transmission worldwide<\/td>\n<\/tr>\n
ACAR<\/td>\nAluminium over aluminium alloy strands<\/td>\nAlloy core<\/td>\nCorrosion-sensitive routes needing more strength than AAC<\/td>\n<\/tr>\n
ACSS<\/td>\nAnnealed aluminium over high-strength core<\/td>\nCore, essentially all of it<\/td>\nUp-rating an existing right of way; high operating temperature<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Where copper still wins, and why<\/h2>\n

The underground cable is the last bastion of copper in the cable industry, and the reason for that is the issue of space. A trench, duct, or cable tray has a predetermined space, and any extra square millimeter of the conductor needs to be justified by digging, ducting, and pulling efforts. Wherever there is a need for a large cross-section, copper conductivity wins the competition. Underwater use creates one more rationale for copper use: strong construction for long supportless runs and at the entry points where cable is pulled.<\/p>\n

In electrical devices the picture is even clearer. Busbars, motor and transformer windings, contactor coils, control wires are all made of copper, since the housing has a fixed size, and connection quality manifests itself more than price of metal. 3,200 A of electrical busbar made out of copper should have about 1.6 times smaller section made of aluminum which normally does not fit. DC traction (metro third rail and overhead systems, arc furnaces, electrolytic plants) remains with copper for the same purpose.<\/p>\n

Then there is the conversion argument: any current system constructed from copper cannot be transitioned into aluminum without changing all the assumptions regarding ampacity, fault ratings and protection settings at the same time.<\/p>\n

The failure modes that gave aluminium a bad name<\/h2>\n

Aluminium has gained a bad reputation that it has largely earned \u2014 but it is not the material’s fault. During a time of unprecedented copper costs, it was then assumed that the same technologies, devices, and torque values being used on copper would also work when using aluminium in homes in North America. Three properties then played into the situation.<\/p>\n

First, aluminium reacts with oxygen and forms an oxide coating, which is an insulating material that has a melting point of around 2,072 \u00b0C; thus, it is good for corrosion-resistance and not good for screw terminals. Secondly, aluminium expands significantly more than copper during thermal cycles; therefore, the connection made is going to be loose after a great number of thermal cycling. Thirdly, since aluminium is anodic to copper, the presence of moisture causes galvanic corrosion of the contact whenever there is a direct contact of the two metals.<\/p>\n

All these problems lead to one classic failure: a receptacle getting warm enough to develop arcs. The solutions for making modern aluminium wiring safe are oxide inhibiting compound applied directly at connections, CO\/ALR-rated devices used especially for aluminium conductors, bimetallic transition connections between copper and aluminium, as well as torque values calculated and considered in respect of expanding properties of aluminium.<\/p>\n

For anyone working on existing aluminium branch circuits, the diagnostic is heat rather than appearance. A termination that has begun to fail will usually show discoloured insulation, a scorched device or nuisance tripping long before it fails outright, and the same fingerprint \u2014 warmth under light load, then trips that make no sense \u2014 is how you catch a breaker that has gone bad<\/a> at the other end of the circuit.<\/p>\n

Matching the conductor to the voltage class<\/h2>\n

The way power is transmitted changes as the transmission voltage changes, and the change is caused by geometry and not economics.Above roughly 220 kV, lines carry more than one conductor per phase, and the same logic that governs the difference between high voltage and low voltage<\/a> design decides how many. A 400 kV line commonly runs two or four sub-conductors per phase in a bundle rather than one very large conductor.<\/p>\n

The change in power transmission has to do with inductance and corona effects. Inductance of a power line is determined only by the physical radius of the wire, and the increase of the radius of a single wire does not have much influence on inductance. To make it effective, wires are bundled into a number of smaller wires, therefore, the effective radius increases with the number of wires, while maintaining the electric field at the surface low enough to avoid corona. Hence, the aluminum content in the wires grows with voltage, and the design of the wires is done beforehand, thus it does not depend on the manufacturer.<\/p>\n\n\n\n\n\n\n\n
ACSR code name<\/th>\nStranding Al \/ steel<\/th>\nOverall diameter<\/th>\nDC resistance at 20 \u00b0C<\/th>\n\u0422\u0438\u043f\u0438\u0447\u043d\u043e\u0435 \u043f\u0440\u0438\u043c\u0435\u043d\u0435\u043d\u0438\u0435<\/th>\n<\/tr>\n
Dog<\/td>\n6\/4.72 + 7\/1.57<\/td>\n14.15 mm<\/td>\n0.2745 \u03a9\/km<\/td>\n33-66 kV lines<\/td>\n<\/tr>\n
Panther<\/td>\n30\/3.00 + 7\/3.00<\/td>\n21.00 mm<\/td>\n0.1390 \u03a9\/km<\/td>\n132 kV lines<\/td>\n<\/tr>\n
Zebra<\/td>\n54\/3.18 + 7\/3.18<\/td>\n28.62 mm<\/td>\n0.0688 \u03a9\/km<\/td>\n220 kV and 400 kV, bundled<\/td>\n<\/tr>\n
Moose<\/td>\n54\/3.53 + 7\/3.53<\/td>\n31.77 mm<\/td>\n0.0561 \u03a9\/km<\/td>\n400 kV, twin or quad bundle<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

These names are derived from national conductor catalogs, while the figures that follow \u2014 including diameter, stranding, resistance, and geometric mean radius \u2014 are key considerations in designing a line. The first aspect concerning the substance of the conductor is resolved far in advance of reviewing the conductor table.<\/p>\n

\"Matching<\/p>\n

Ampacity, temperature and terminal ratings<\/h2>\n

The lower conductivity of aluminium extends to the ampacity tables as well. With the same conductor size, aluminium is able to conduct around 78-80% of the ampacity of copper at the same temperature rating for insulation. For example, a 1\/0 conductor rated at 75 \u00b0C presents an ampacity of 150 A in copper and an ampacity of 120 A in aluminium. In order to achieve the same ampacity level, it is necessary to use a larger conductor \u2014 the general rule is to use a conductor that is two AWG sizes larger than in copper.In the end, this brings the issue of the space \u2014the aluminium conductor that conducts the required current requires different raceway sizes, different lugs and more space at the panel.<\/p>\n

Two details in the code create most cases of errors in the field. The first one is the fact that ampacity depends on the temperature ratings of wiring and terminations. A 90 \u00b0C insulated conductor connected to a 75 \u00b0C rated terminal can only be used at the lower figure unless the assembly is listed otherwise, and that listing is exactly what a UL 489 molded case circuit breaker<\/a> declares in its terminal temperature rating rather than in its marketing literature. The second detail is that aluminium connections must be made using connectors that are listed as suitable for aluminium wiring, using the aforementioned torque and the oxide inhibitor according to the specifications of the connector manufacturer.<\/p>\n

What this means for switchgear and terminations<\/h2>\n

At this stage, the decision made by the conductor is no longer a decision regarding the wire, but one concerning the switchgear. The use of aluminium feeders requires that every piece of equipment connected to the wires is rated for both aluminium and copper; the termination equipment has to be bimetallic involving an aluminium and copper connection wherever aluminium is used with copper.<\/p>\n

HUYU’s manufacturing line makes components such as MCBs, MCCBs, air circuit breakers, contactors, relays, current transformers, surge protection devices, automatic transfer switches and PV combiner boxes. We do not produce wire, thus we do not view it to be up to us to make the choice between aluminium and copper.What we do is supply equipment whose terminals are rated for both, with the torque and conductor-range data published \u2014 a DIN-rail \u043c\u0438\u043d\u0438\u0430\u0442\u044e\u0440\u043d\u044b\u0439 \u0430\u0432\u0442\u043e\u043c\u0430\u0442<\/a> is only a 63 A device to the extent its terminals accept the conductor you bring to it.<\/p>\n

As we have learnt from our experience with failures in the field, it is important to remember that whenever a feeder changes material during a run, the junction of that change must be at a designated terminal or at a bimetallic connector \u2014 never half-way along a run with a split bolt and a piece of tape.<\/p>\n

How to decide on a real project<\/h2>\n\n\n\n\n\n\n\n\n\n
\u041f\u0440\u0438\u043c\u0435\u043d\u0435\u043d\u0438\u0435<\/th>\n\u041c\u0430\u0442\u0435\u0440\u0438\u0430\u043b<\/th>\n\u041f\u0440\u0438\u0447\u0438\u043d\u0430<\/th>\n<\/tr>\n
Overhead transmission and distribution<\/td>\nAluminium (ACSR \/ AAAC)<\/td>\nWeight, span length, tower cost, diameter and corona<\/td>\n<\/tr>\n
Underground and submarine cable<\/td>\nCopper, sometimes aluminium for large LV<\/td>\nCross-section is expensive; robustness at landing points<\/td>\n<\/tr>\n
Switchgear busbars and control wiring<\/td>\n\u041c\u0435\u0434\u044c<\/td>\nFixed enclosure volume; connection reliability<\/td>\n<\/tr>\n
Motor and transformer windings<\/td>\nCopper; aluminium in cost-driven distribution units<\/td>\nWinding space, losses, heat dissipation<\/td>\n<\/tr>\n
Building feeders, larger circuits<\/td>\nAluminium for size and cost; copper for tight routes<\/td>\nTrade-off between metal cost and raceway space<\/td>\n<\/tr>\n
Existing installations<\/td>\nMatch what is already there<\/td>\nAvoid re-rating studies and mixed-metal terminations<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

System-level decisions often push the answer one step further. On a large industrial site, the conductor material interacts with the distribution architecture \u2014 how many transformers, how long the MV runs, how much MV switchgear \u2014 which is why enterprise-scale distribution systems<\/a> are designed as a whole rather than conductor by conductor, and why optimising the architecture usually saves more than the metal swap does.<\/p>\n

\u0427\u0430\u0441\u0442\u043e \u0437\u0430\u0434\u0430\u0432\u0430\u0435\u043c\u044b\u0435 \u0432\u043e\u043f\u0440\u043e\u0441\u044b<\/h2>\n

Is aluminium or copper better for power transmission?<\/h3>\n

Aluminium is preferred for overhead lines by an enormous factor, with more than 90% of the global network employed in its use. Copper is better suited for underground lines, equipment, or situations where the cross-section is predetermined. They both have their strengths; the question then is which constraint applies to the situation in question.<\/p>\n

Why is aluminium used instead of copper in overhead lines?<\/h3>\n

This is because an aluminium conductor with the same resistance weighs only approximately half as much and costs about 35-50% of the price of the copper equivalent. The fact that the weight is half makes the spans longer and more towers and smaller foundations are needed to properly support the structure.<\/p>\n

Can copper and aluminium wires be connected directly?<\/h3>\n

Avoid using it in any damp or exterior area. Aluminium is electropositive to copper, which can cause galvanic action in the presence of moisture within the connection. Therefore, make sure to use special bimetal connectors designed specifically for the two metals.<\/p>\n

Does aluminium wire carry less current than copper of the same size?<\/h3>\n

Indeed, typically the Copper rating is around 78 to 80 percent for the same insulation temperature of the insulation. If you want the same amount of current and voltage, you’ll use about two AWG sizes up which would require bigger conductors and therefore bigger sizes of both raceways and lugs as well.<\/p>\n

What is ACSR and why is the steel core there?<\/h3>\n

The Aluminium Conductor Steel Reinforced (ACSR) is formed by placing a steel wire core at the centre of several layers of aluminum wires. The role of steel is to take the tensile stress that the hard drawn aluminum cannot manage on long spans, while the aluminum is responsible for carrying electrical current. Since steel is located in the central part of the conductor where the place for the electrical current is minimum, almost no electrical loss occurs.<\/p>\n

Is aluminium wiring in a house dangerous?<\/h3>\n

Not per se, but it does require proper device installation. The mistakes that happened in the 1960s and 1970s can be attributed to the use of aluminum wire connectors with devices that were not rated for such conductors, but were utilized without the appropriate installation or proper torque. Nowadays, with the use of the oxide-inhibiting compound, the devices rated for CO\/ALR rating, as well as bimetallic gadgets the process works correctly and efficiently under the condition that those requirements are fulfilled.<\/p>\n

\u0421\u0441\u044b\u043b\u043a\u0438<\/h2>\n