Opinion, Copper bus or Aluminum bus

[Fred B]

If cost not issue would you prefer copper bus or aluminum bus for a load center?
Reason you would use one over the other?
Circumstance that would necessitate one over the other?
I know copper is more expensive by about $50 on a 200A 40/60 load center.

 

[infinity]

If cost is no issue copper every time.

 

[Rick 0920]

Copper if cost is no issue. It has a lower resistance than AL. A Lower coefficient of thermal expansion. Corrosion is not as much of an issue with copper. Copper does not react with water like AL does. Copper is less brittle.

 

[synchro]

Copper if cost is no issue. It has a lower resistance than AL. A Lower coefficient of thermal expansion. Corrosion is not as much of an issue with copper. Copper does not react with water like AL does. Copper is less brittle.

Copper also has almost twice the thermal conductivity as aluminum.

 

[petersonra]

They are equal in my opinion. AL might be a slight preference, but both will work just fine.

 

[jim dungar]

If the bussing is tin plated it makes little difference which material it is.
Resistance is not really a factor. Panels, switchboards, and transformers are rated and tested based on handling a specific amount of current. Dimensional difference is only a concern of the equipment designer.

In general, the enclosure material concerns me more than the bussing material.

Of course certain ambient environments, like corrosive atmospheres, must be considered.

 

[4-20mA]

Copper also has almost twice the thermal conductivity as aluminum.

Why isn't copper used for heatsinking more often? Or is it? Because of cost only? For twice the benefit, it seems like a good option regardless of a slight cost difference.

 

[synchro]

Why isn't copper used for heatsinking more often? Or is it? Because of cost only? For twice the benefit, it seems like a good option regardless of a slight cost difference.

I think cost is the main driver. Presently copper is about 3.6 times more expensive per pound that aluminum, and about 12 times for the same volume of material.
I have seen a copper slab used as a "heat spreader" between power transistors and a large heat sink made of aluminum or even Zamak ( a zinc alloy). In this case the heat is sourced by a relatively small semiconductor "die", and so the thermal resistance is most important near this source, but it becomes less important as the heat spreads out to a larger cross sectional area.

 

[GeorgeB]

Aluminum heat sinks are frequently extruded and sawed to length. I've (just me) never seen copper extruded, and cutting it is more difficult than with aluminum.

@synchro reasons are more important.

 

[kwired]

Both tend to be tin plated in most cases anymore.

Bolt on vs plug on breakers may be somewhat a bigger consideration.