Choosing a right High Guage Wire

It depends on the physical use of the wire? If this is to be a flexible lead wire then you need something like rubber cord or single lead of polyurethane with a high strain count, something in the neighborhood of 19 strains or more.

If this to be in side a cabinet (enclosure and not meant to move around), then use MTW type wire (Machine Tool Wire). If you are passing this wire in race ways or maybe in some situation where oil, grease or something may come in contact with it, use THHN type wire..

These wires I just quoted are good for 600V except for the rubber cord or polyurethane, those you need to make sure you have the spec'd voltage when ordering. They normally come in 300,600 and up in voltages.

For 20 AMPs on medium runs, 12 AWG is good. You didn't specify the length of the run, which is important. In your case, if you are over 150 feet or more, I would drop down to 10 AWG. The idea it to not have no more than ~ 5% voltage drop on the load side. Getting the ohms per unit can help you with this calculation. Remember that many unit measurements are in 1K foot unit. But you do need to check the unit they are using when using the table data.

P.S.

If you are in need for a series of wires that may be in some sort of constant articulation movement device, then use FESTOON wire, which is a ribbon type of wire designed to roll for movement.

Also remember, this MTW and THHN is intended to be inside a cabinet or race way, like EMT pipe, greed field, Liquid tight flex, armor (MC) etc.

Jamie

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How long does the run have to be?

The maximum current a wire can carry depends on its environment. In some cases the Electrical Code or other rules may specify limits. For normal house wiring, #14 can be used for up to 15 amps, #20 to 20 amps, and #10 to 30 amps when used in the usual two-wire cables. If multiple wires are run in a bundle or conduit, the allowable current (ampacity) is reduced. For long cable runs, a larger wire may be required to reduce voltage drop.

The voltage rating of a wire depends on insulation type and thickness, and is independent of current handling capability.

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Peter Bennett, VE7CEI  
peterbb (at) telus.net
GPS and NMEA info: http://vancouver-webpages.com/peter
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You mean #12, not #20.

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You can't have a sense of humor, if you have no sense.

Hookup wire is usually made in 300 V and 600 V ratings.

What are you going to use the wire for? The current rating varies for single conductor, bundled conductors, sheathed or open, and if used to wind a transformer.

Find a copy of the ARRL handbook for a lot of useful, basic information. They are worth the price, if you can't borrow a copy. :)

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You can't have a sense of humor, if you have no sense.

The word is 'strand or strands', Maynard. You claim to work for a wire manufacturer, and can't even use the right word. So much for you working for 'The original Brand Rex'. :(

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You can't have a sense of humor, if you have no sense.

Please do not take offense but if you are asking these questions for "hookup wire ... between 20A and 400 volts" then you are unlikely to be able to properly implement or even evaluate the answers. This isn't like rewiring a table lamp. Hire a qualified electrician.

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Rich Webb     Norfolk, VA

Rich Webb submitted this idea :

That would be my answer too. There are too too many variables in this question to rely on an answer that may well be right out of context.

20 amps at 400 volts is a lot of power for "hookup" wire and being used by someone who does not understand the simple math involved.

It is no discrace to not know and ask but the problem is way beyond the limits of simple usenet answers.

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John G

Wire rating is based on temperature rise typically for a bundle. Any gauge wire will handle 20 amperes of a while and then melt or glow red or feel warm or be appropriate. Google for wire gauges at wire manufacturers' and get a table of reasonable gauges for you application.

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So where are we?
  Not the street address.
  Not the city.
  Not the country.
  Not the Earth.
  Not the Solar System.
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So where is the Brane?
Where are we?

Life is but a dream!

Yes, but if the OP said what he was actually trying to do, instead of posing what he (mistakenly) thought was a valid technical question we could give him better guidance (and it might actually be a simple, low risk problem).