On image KTA electrical trunking (aluminum) Canalis 1250A to 3200A – Schneider Electric
Later years with copper being the material of choice for high power trunking in the UK, but aluminum reigns supreme in the rest of the world, Schneider Electric looks at the aluminum case on copper trunking at a time when material cost has a significant impact on specification choices
The company tackles industry misperceptions and sheds light on some of the common arguments against its widespread use, including performance, weight, expansion, and cost.
When it comes to performance and strength, many designers consider copper to provide higher performance than aluminum for the same bar rating. However, the differences are marginal, as Lee Jones of Schneider Electric explains:
“Tests reveal that under a 1400A load over 30 of 1600 meters of Canalis busbar trunking, the voltage drop for aluminum was only 0.32%, equated to 0.30% for copper. This equates to a difference of only 5 mV.
On longer runs, we analyzed a run of Canalis 3200A aluminum raceways at 2700A and at that level we discovered that the system had a volt drop percentage of 3.2%. According to wiring regulations, the maximum voltage drop on the power circuits of a private power supply is 8%. As an indication, 40% of this 8% is lost in the sub-distribution and the balance in the final wiring of the circuit. With a copper wire system, it is common practice among designers to increase the cable size to overcome voltage drop issues. However, with busbar trunking it seems preferable to use a copper conductor. In the calculations,
Tests have shown that over a length of 250 meters where the load is 2700 A, the voltage drop on a 4000 A aluminum trunking is 2.70%, which is minimal compared to a voltage drop of 2.53% on a 3200 A copper line – equivalent to a difference of only 675 mV or 0.17%.
Lee adds, these instances at 250 meters carried the product to the highest volt drop of the sub-distribution. These were extremely long runs, but they indicated the length of runs where volt drop could become an issue.
Lee continues: Installing aluminum busbar trunking with equivalent implementation means that their capacity is normally 16% to 25% larger than copper busbar trunking. However, it is 40% lighter, giving contractors a trade-off, as it is easier to handle, more maneuverable, requires fewer people to install, offers faster installation, and could eliminate the need for lifting equipment. specials – saving time and money for the contractor and the customer. Additionally, the use of aluminum over copper trunking means that the building’s electrical support structures can be lighter.
In response to the view that aluminum expands more than copper, Schneider Electric points out that it is necessary to allow for expansion and contraction at the point of manufacture to ensure a reliable connection. For example, with the Canalis range from Schneider Electric, the joints between each length have an “elastic connection joint” which automatically compensates for expansion.
In addition, the seals in fittings from Schneider Electric’s busbar trunking range are silver plated and not tinned as is commonly used by other manufacturers. This metal provides the best electrical conduction and abrasion resistance as the bar moves along the joint, ensuring the longevity of the installation. In fact, ASEFA tests show that silver plating performs 12 times better than pewter. Additionally, copper and aluminum trunking are both tested to BS EN 60439-2, so there is no difference between the standards used.
What about the cost?
The last argument concerns the cost
Even using higher rated aluminum trunking than copper, it still offers financial savings. In cost comparisons between 3200A copper and 4000A aluminum, a saving of 23% was achieved.
This increases to 35% when comparing a 3200 A rating on an equal area.
Lee Jones comments: “Choosing an aluminum bus trunking has many advantages which means designers and contractors should not be deterred from using it. The difference in performance between the two materials is marginal at shorter lengths, and at longer runs where voltage drop may be an issue, designers can choose a higher quality aluminum bar. Additionally, no special stampings are required on our range due to the use of silver on the seals.
Thus, bar trunking can be used as an alternative to traditional Pakistan cables and increasingly popular in the construction market, contractors can take advantage of faster installation times, while providing their customers with a system that can be upgraded and reused as building usage changes over time.