Bus bar specs calculation

[tonyg]

Hi!
I've found various info on Google searches but wondering what would be the right way to size my busbar.

For wires, I can look in the table of the providers for the wires I buy. They have an amp specification in accordance to their size.

But with a bare copper tape / bar this information is not easily found and often contradictory numbers are found on different websites.

Should I simply do width X thickness and then look at the ampacity of same sized wires?

Cheers,
Tony

 

[DougfromdaUP]

Here's some good information on capacity.

 

[rhino]

And you have to remember when dealing with ampacity of wires they have to take into account the insulation rating whereas a busbar does not (unless you add your own insulation to it).

 

[rhino]

@DougfromdaUP has right site but want the DC busbar table: https://www.copper.org/applications/electrical/busbar/busbar_ampacities.html
and note it does show ampacities based on expected temperature rise for that ampacity. So the reason why you get conflicting info is because of a lot of tables don't tell you how much they expect the busbar to rise in temperature given the amps that it is "rated" for. This is also why you see some busbars on Amazon that look way too small to handle a certain amount of amps but technically it can handle it but it would get a lot hotter then you would want and may start melting something.

 

[rhino]

Here's example of one on Amazon that does actually match what the table shows:

https://www.amazon.com/dp/B08JKY2BYD

it is 1/4" x 1" tinned copper rated for 400A and if you look at the table the table shows it handling 403A in a horizontal position. If you were pulling 400A through that busbar it would rise 30°C above a 40°C ambient temp. So the bar would be at 70°C/158°F. It is mounted on ABS plastic which as a limit of 221°F.

 

[tonyg]

Thank you, everyone!
Regarding solar and anything around it, there's no better place to get info. I'm glad I asked, it spares me extra expenses, as I already have the 1/4" x 1" pure copper bar. There won't be more than 300A traveling through it, so that's safe to use.

Thanks again!