wire diameter for specific loads

[rmetzger]

I'm designing a link for a power supply (fail-safe system) and am looking for some information on the cross sectional area of conductors needed to carry the load.

The scenarios I have to design for are as follows:
500VAC at both 60Hz and 400Hz, with 4 different current loads (10A, 20A, 50A, and 100A).

The conductor will be silver plates copper solid wire/bar. Any help to find a equation/calculator to determine the appropriate cross sectional area would be greatly appreciated

 

[RawDog]

Hey all you need to evaluate the wire gauge for is Amps...the freq. is not relavent unless doing some communication signal design. So go to:

http://www.bnoack.com/index.html?http&&&

http://www.bnoack.com/data/wire-resistance.html

Click (CABLING) on left scroll menu
Click (POWER CABLE AMPERAGE) and read on....It has a list of gauge to amps for power design.....hope this helps!

 

[rmetzger]

The voltage does not have any bearing on size?

thanks for the link BTW.

 

[RawDog]

Voltage has no bearing on size cause wires/cables are rated in Amps/cm^2. Like a stun gun that has 1,000,000Volts and 30something gauge wires...this is because the amperage is like .000001 amps. Some really high power lines are rated in Power/cm^2 but this is only for appilcations the govt. can use...like power generators and whatnot...hope that helps..Anyone who says freq. is important is relying on their sig. com. classes from school, in which characteristic impedence plays a major factor in the signal integrity and degridation...Hope this helps!

 

[rmetzger]

Yup - that helps a ton. Thanks for all the info.

 

[jraef]

I want to add however that voltage does no make a difference in conductor size, it is important as to the the insulation and spacing. Since you mention 500VAC, the spacing between live components is critical, as compared to 300V and under.

"Venditori de oleum-vipera non vigere excordis populi"

 

[VEBill]

Although it does not matter in this case where the voltage is already decided, but in the case of power lines - voltage matters (in relation to conductor size) twice as much as you might think.

For a given power, higher voltage means less current and thus less I*R voltage drop. This is the obvious advantage.

But higher voltage also means that any given I*R voltage drop matters less in proportion to a higher voltage. In other words, a 1kV voltage drop is serious for a 6kV line but it is a non-issue for a 500kV line.

The advantage (in terms of reduced voltage drop) goes up as the square of the voltage (for a given power).

None of this matters in this case.

 

[rmetzger]

Can you pass any pertinent info regarding conductor spacing or links to information?

thanks

 

[jon1]

There is a standard for the European Union, but it is in the medium voltage standards, which I am not acquianted with. The requirements would of course depend on any coating or wire insulation, humdity, condensation, contamination, finger guarding, earthing, labeling, etcetera.

 

[jraef]

Spacing considerations are usually specified in whatever testing or regulating authority has jurisdiction at the point of use. For instance in the US, the National Electric Code delineates spacing for the installation of equipment, while UL and ANSI dictate it for the manufacture of equipment. You should be using all of those references in your design if your equipment is going to end up here. Canada has their own codes and authorities, but are for the most part the same. Elsewhere in the world you would need to look at IEC as a starting place, but realize that many countries have their own specific requirements as well.

"Venditori de oleum-vipera non vigere excordis populi"