Ampacities of platinum and stainless steel

[grandmarquis]

I am having difficulty finding ampacities of materials other than copper and aluminum. I have a special interest in using stainless steel or possibly platinum. In any event, I will be using 10 feet or less, probably only 4 feet. What AWG of platinum wire or diameter of stainless steel wire rope would I need in order to carry 20 amps.

 

[dpc]

Bare conductor or insulated? Insulated conductors are limited by the temperature of the insulation.

Is this something that has to meet National Electrical Code or some equivalent code?

A ratio of resistivity between copper and the the metal in question should get you pretty close.

I doubt if you will find ampacity tables in AWG for platinum or SS.

 

[grandmarquis]

It will be bare wire. I don't neet to meet any codes. I am experimenting with electrolysis.

 

[grandmarquis]

Sorry, let me claify my last. These wires will be used inside the water cell. There may be a few inches that are dry, the rest will be submerged in water. I'm trying to see how fast I can split out hydrogen and water. Using plates, foils and probes do not seem to yeild as fast of a reaction as do coils of wire.

I'm not concerned about codes. This is simply experimenting for my buddy and I for a weekend project.

 

[dpc]

So, 304 SS has about 40 times the resistance of copper and platinum has about 6.5 times. So as a first approximation, I'd increase the cross section by this factor when compared with copper.

 

[JJHorak]

You will not really reach the temp limits of the conductor if it is in close proximity to the water. Also, I suspect platinum and SS can get quite a bit hotter than copper and aluminum before being damaged by heat.

 

[itsmoked]

Time's correct. You don't want your water boiling. The most overlooked, to the point of ridiculous, aspect of HHO generation is the general race to how-much-how-fast at the complete exclusion of efficiency. Without efficiency the whole point is lost.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[edison123]

Platinum ??? Man, that must be a heavily funded project.

* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *

 

[grandmarquis]

Thank you everyone. It is refreshing to see intelligent responses.

Yes, this is going to be one of those “…to the point of ridiculous, aspect of HHO generation is the general race to how-much-how-fast at the complete exclusion of efficiency…” moments, as itsmoked put is so perfectly. This is just a fun experiment. As long as we don’t blow up a battery or melt a wire and hurt someone, it is just fun and games. People performing this for use of the HHO need to consider efficiency to be one of their topmost priorities. There are several aspects of efficiency, not just the electrochemical reactions. There is also the cost of manufacturing, availability of materials, weight, power source, overall size of system, etc. It never ends. But, for our weekend project, it is about screaming fast HHO generation. You know, even if it were for use in a generator, automobile, or other, this type of experiment would not be totally unjustified. It has been my experience that more knowledge equals more power and more ability. It certainly never hurts to have a greater understanding of a situation or a greater understanding of all operational limits and extremes. Just some food for thought.

 

[SteveFehr]

The heat-to-water dissipation is going to be much faster than heat-to-air-through-insulation. Honestly, I'd throw out the NEC tables and do calculations from scratch based on the resistance of the metal and heat dissipation. As already noted, you don't want your water boiling! Size them for what you feel is an acceptable amount of heat dissipation via I^2R.

Will you be switching to copper just outside the bath? If significant portions of these electrodes will be out of the bath, you might have to also consider heat transfer along the length of the electrodes, too.

A lot of this is difficult to calculate and may simply be experimental.

 

[dpc]

FWIW, Stainless steel is commonly used for making power resistors - it's not a great conductor.