Current carrying capacity of copper

A. The answer is complicated by the fact that there is some thermodynamics involved in the solution, and unless you can specify wire resistivity, ambient conditions including insulation, humidity, etc. for heat loss, an expert mechanical engineer will not be able to do the simulation job for you, and you may still have a theoretical answer of no use. So I would simplify things this way:

1) According to wire gauge, each wire/strand is rated for a certain current limitation. Just look at the table. Somebody has done this work for us a century ago. You may extrapolate information you need from this table.

) For your specific ambient and insulation conditions, do an experiment. Get a variable current power supply and pass increasing current through the wire of interest. Attach a thermocouple to the wire and measure the temperature. An engineering college lab could help you in the case you do not have the set up.

3) A typical 0.25" (6.35 mm) dia. pure copper rod can handle up to 150 amp current without getting hot at 75 °F ambient and no insulation. See if this helps extrapolate.

Hard chrome plating rectifier bus bar sizing

How do you size the bus bars (from rectifier to tank).?

The end-user is using 100 x 10 x 3 Aluminium bus bars for 3000 A and 16 V.

Another rectifier is 100 x 4 x 3. 1500 A and 10 V.

Can you please advise on any selection table for sizing of bus bar and also the losses with Al bus bar and Cu bus bar?

How do you measure the current in these bus bars? Which portable meter will provide reasonably accurate values?

Kumar

Full name please, Kumar -- this is a place of camaraderie not anonymity :-)

The quick way to size bus is (in english units) 1000 A / sq. in for copper and 600 A/ sq. in for aluminum. Bus sizing is irrespective of voltage within the common range for plating.

Charts and more detailed calculations comprise the "Anode and Cathode Rod and Bus Systems" chapter of the Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] .

A. As far as I know, (I heard it from someone working in my company):
First you should know the current density of the conductor; let's take, for example, copper has 4.02 Amp/sq. mm. as current density. So you want to pass a 2A current thru a copper conductor then you need a conductor of area:
area = current in Amps/current density.
area = 2/4.02
area = 0.5 sq.mm
They use this formula for calculating the thickness of the busbar that they use in big electrical panels.

A. Copper current density allowable is 1.6 A/mm2

A. Hi folks. The allowable current carrying capacity is actually defined as the amount of current that can be carried without melting the conductor or the insulation. Googling "current capacity of copper conductors" will immediately produce a dozen sites with the same definition and same charts.

But in many cases we don't want to put nearly that much current through the conductors. In the electroplating industry we have always used an allowable current of 1000 A / square inch for bare DC busbar, which equates to 1.55 A/mm2 -- essentially the same as Swamulu's number. This is empirical, based on the recognition that we don't want a large voltage drop across the conductors because it would interfere with the plating process, and waste a lot of energy, and a hot bare bus bar introduces the real possibility of operators getting burned or starting a fire.

I think Mandar's & Rajiv's numbers may be valid for some applications but are much too high for low voltage DC bus bars. Please see thread 50556, "Copper Bus Bar Sizing for DC low-voltage high-amperage" for further discussion of low voltage bus bar runs.

Regards,

A. Hi Mayank. You are welcome to post your question and anyone is welcome to answer it, but this is a metal finishing site and may not attract electrical engineers experienced in the rather specialized field of air circuit breaker design.

Regards,