Wire Ampacities

[Gillbot]

I'm drawing a blank on how to correlate wire ampacities. I have two ~15v circuits with a 25ft one way run. One needs to carry about 100 amps, the other about 2 amps. What gauge wire is needed for these? I don't need to go overkill since this isn't a quality needed circuit and voltage drop isn't much of a concern, I just wanna be sure I don't need a fire extinguisher.

 

[KingNothing]

That can't be a real word.

 

[95SS]

100 amps = 2ga
2 amps = 18ga

edited for distance

 

[KLin]

Text

 

[Gillbot]

Originally posted by: 95SS
100 amps = 4ga
2 amps = 24ga

Thanks! I thought the 4AWG would be ok but wasn't sure about the 2amp circuit. Been too long, might have to go dig out my electrical handbook.

 

[Gillbot]

Originally posted by: KLin
Text

I have the tables here in front of me, but I can't recall the derating factors for distance.

 

[PowerMacG5]

Originally posted by: KingNothing
That can't be a real word.

How can that not be real world? My school district has spools of wire rated for 240 V at 75 Amps.

 

[Batti]

He said "word" as in Ampacity is not a word (but it is).

Look here for voltage drops, etc. Are you really running only 15 volts? If so, these tables won't help as much.
Electrician.com

 

[Gillbot]

Yep, it's 15v open circuit voltage.

http://cofba.org/users/gillbot/Welder/smP1010319.JPG

Home-made welder using a 3.5hp briggs motor and a 97 amp GM alternator.