I am designing a 12vdc system where I will have a row of fuse holders. I would like to connect the row using a bus bar type strip of solid aluminum. If I know the exact dimensions of the strip is there a formula for calculating the amperage it can handle?
The easiest way would be to convert the bar to the closest circular mils. This would give you a close enough value to use a standard lookup chart on AL wire. If you need more info, post the dimensions. Here is a site for a free calculator for 20 days. Near the bottom. You have to RUN the app from the site and it will install it.
The voltage is irrelevant to this problem. I don't know exact amperage's but I would approximate the bus bar thickness (at its narrowest point) and compare it to a similar gauge for a copper wire. Using a bus made for small glass fuses I would assume your bus is at least 5-7mm thick. That would be equivalent to a 2 gauge copper wire which is rated a 60 amps (conservatively) This will give you 12 x 60 720 watts total load.
Al resistance is 0.028 ohm*cm. For a current I flowing through it we have: I^2*R, this energy is converted into heat hence: I^2*Rk(Tc-Ta) where kthermal conductivity of Al, Tcconductor steady state temperature C, Ta ambient temp C, Rtotal resistance of conductor ohm, Icurrent in amps From these equations you can find I the ampacity at steady state.
