How to size a "post" to amperage 1

[RyanMcCauley]

Hello,

I am an ME and have virtually no experience in the electrical world. However, I have been tasked to determine the required cross-sectional area for a "post". (I'll attach an image to clarify).

I have 15 VDC & 225 amps incoming to this "post". This will be made out of Titanium. Is there a way to determine a safe cross-sectional area for the post with this load?

Thanks in advance!

 

[DRWeig]

How hot is it allowed to get? Titanium is about 12X the resistance of copper for equal cross sectional area and length.

It will be interesting to see what the group comes up with.

Good on ya,

Goober Dave

 

[DRWeig]

Oh, I forgot to stick in my guess (please wait to hear from others, I did NO thorough analysis):

I'm going to say a 1/0 AWG copper (bare in air) is good for a little over 250A, and 1/0 is about 0.33" in diameter. You need 12X the cross-sectional area to equal it with titanium, so something around 0.57" titanium.

Again, don't rely on my answer... There are others in this forum with more experience in such matters. And whatever you decide, you'll need to test it thoroughly.

Good on ya,

Goober Dave

 

[DRWeig]

Oops, should have been 1.14 inch diameter. Bad math...

 

[potteryshard]

The usual rule-of-thumb allotment for copper is 1 square inch of cross-section per 1000 Amps. That is a bit on the conservative side, but is good for things like terminals where one can't rely on the favorable surface area to cross-section ratio exhibited by wires for air cooling. That would suggest 3 square inches. Thermal conductivity may enter this as well as electrical.

 

[wareagle]

Ryan
Why does the post have to be made of Titanium"?

 

[PHovnanian]

I'm wondering about how the hardness of titanium will affect contact resistance between titanium to titanium as well as dissimilar metal current carrying junctions.

 

[RyanMcCauley]

Thanks for all the replies!

wareagle, we chose Ti for corrosion purposes...seawater will be flowing through one side of this connection.

Approximately 30 gpm, which will also aid in cooling. We plan on using a conductive paste to help with contact area. All of the material will be Ti, so no dissimilar metals.

I also forgot to mention, the length of the post will be approximately 1-1/8". I'm not sure if that will factor into the equation or not.

Thanks again for all the input!

 

[NAZ55]

circular mils wise it's approximately 7 times and diameter wise approx 3 times the size of copper. 1" diameter is plenty in my opinion.