# how much current can AWG wire handle

• posted

Hello,

Does anyone know where I can find out how much current specific gauges of wire can handle? I've looked up web pages on it, but can't figure out what they mean... for example at

There's a column that says: Current Carrying, and another that says Fusing Current

I'm interested in figuring out if 20 AWG wire can handle steady DC of

7.25 Amps, for 20 AWG is says Current Carrying: 1.46 Fusing Current: 58.4

? I don't get what they're saying.... other websites have been similarly confusing..

Much Thanks

• posted

then Jim's Engineering Page, then Wire Table.

# 20 wire can carry any current you like, up to the fusing current. It is all a matter of how hot you are willing to let the wire get. The referenced table above will let you calculate the temperature rise of a wire over ambient for any arbitrary current and gauge.

The Current Carrying is how much current the wire can handle for a given rise in temperature over ambient. There should also be a note that the temperature rise will be more than calculated if the wires are in a bundle together. An unbundled #20 wire at 7.5 amps will rise about 30F (15C) over ambient, which is pretty warm. Your call.

Fusing current is the current at which the wire will melt.

Jim

• posted

The current carrying capacity in the listed table is based on 700 circular mills per amp, a very conservative number for wire wound inside a transformer where heating is an issue.

The National electric code specifies current carrying capacity for open wires or house wiring for example about twice that or 300 to 350 circular mills per amp. This gives 20 AWG wire about a 3 Amp rating.

What is your application? What is the duty cycle? What is the thermal environment, how hot can it get? Is it in a transformer or in open air and how insulated? How much voltage drop can you tolerate?

• posted

Back in the day, the usual rule of thumb for low-frequency power transformers in continuous use was 1000 circular mils per amp, where a 'circular mil' is the square of the diameter in mils (thousandths of an inch), i.e. 1 circular mil = (pi/4) square mil. The 1000 circular mils per amp rule comes out to 5.07e-6 square metres per amp.

Cheers,

Phil Hobbs

• posted

But before the wire gets too hot, there will probably be so much voltage drop that the voltage at the load is too low, so that might be the more important criterion.

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"panfilero"

** This page say 20AWG is good for 11 amps when used for "chassis wiring" or wires mounted in mid air.

Tallies with my experience.

1 metre of 20AWG will dissipate about 6 watts at 11 amps when used this way.

..... Phil

• posted

In theory 20 AWG can handle 11 amps DC. However, there are other factors to consider, such as insulation, distance, load, voltage drop, etc. This page explains it in fairly simple terms, has the wire gauge chart for DC (Maximum amps for chassis wiring) and has a voltage drop calculator at the bottom.

• posted

AC 43.13-1B shows AWG 20 okay for about 16.5A if you don't mind 80°C rise (eg. very high temperature rated insulation in moderate ambient).

That's for *one wire in free air*, deratings for bundles (two wires are a bundle), and altitude, of course, and the detailed calculations are shown for various situations. May be available on the FAA dot GOV website.

Mostly you'll not want to get anywhere near those current levels or voltage drop will kill you.

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How can a voltage drop kill someone? The lower the voltage at the outlet, the safer it is!

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safer it is!

Idiot.

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the safer it is!

[to group] Could someone buy Michael a sense of humour?
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I have sense of humor, and a deep disdain for the brain dead who continue posting on USENET.

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What you meant to say is you're a pompous ass and don't like what anyone else has to say.

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has to say.

OK, if that thought is what it takes to make you feel like a man. You constantly post misinformation that can cause problems, or cost someone their life. In my book, you are a pathetic fool.

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has to say.

Quote some of this alledged "misinformation".

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else has to say.

That would be almost everything you've ever posted.

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As soon as somebody buys you a clue. Your Siglines speak volumes - someone not sure enough about the relevance of his posts that he has to post a joke-de-jour as a sigline by way of an apology for his lack of wit... If you have a relevant response to make, then make it - otherwise leave this newsgroup to those who seriously want to discuss electronics!

Regards, Pete.

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else has to say.

Thought so, you have nothing.

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If you don't like the sigs, ignore them. That's what the delimiter is for.

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Mil is confusing. A lot of folk in metric countries say "mil" short for millimetre. A metre is considerably different to an inch.

P.S., what's a click?

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