Thread: Max Wiring Amps
View Single Post
Unread 10-03-2004, 10:19 PM   #1
ISoar
Cooling Neophyte
 
ISoar's Avatar
 
Join Date: Oct 2004
Location: Canada
Posts: 7
Max Wiring Amps

In summary: standard power supply wiring sucks for Peltier use, so using multiple wires, or replacing them with larger wire and better connectors is the best solution.

I keep reading about Peltier users with hot wiring. This is a waste of vital cooling power! It isn't safe either. There are some things that shouldn't be overclocked!

How many Amps can wiring handle?

I did some digging. The ATX specification is available from:
http://www.formfactors.org/
It specifies Molex connectors, which info on can be found on the Molex site:
http://www.molex.com/

Our power supplies use:
Molex 8981P - Female 4 position housing
Molex 8980P - Female crimp terminal
Molex 8981 - Male 4 position housing
Molex 8980 - Male crimp terminal

The Molex Product Design Specification states:

Current Rating:
14 AWG - 10 Amps (120 Watts at 12 Volts)
16 AWG - 10 Amps (120 Watts at 12 Volts)
18 AWG - 8 Amps (96 Watts at 12 Volts)
22 AWG - 6 Amps (72 Watts at 12 Volts)

Operating Temperature: -10 C to 85 C

A wiring-only rating of a 30 C rise yields 450 Amps/sq cm, which is about 4 Amps on 18 AWG. This is inline with the oft repeated max value of "about 5 Amps" for power supply wiring.

On a typical supply, an Enermax EG651P-VE, the wiring is 18 AWG and rated for 90 C.

Good 50 Amp continuous connectors for 13 AWG can be gotten from Radio Control hobby suppliers under the name of: Astro Flight Zero Loss 2-Pin Connectors. There are other brands too (Deans = 12 AWG, etc.). You'll also find high temperature (>150 C) silicone wire with high strand counts (more flexible and durable).

I'm shopping for a Peltier supply, and will be using thick welding cable (more strands than battery cable, so again it's more flexible) to avoid voltage drop and wasted cooling power!
ISoar is offline   Reply With Quote