ECN Forum Forums General Topics of the Trade General Discussion Area 18-24AWG wire

Hey guys, I'm working on a low-voltage project, nd I forget how many amps 20-24AWG wire can carry. Can you fill me in here? Thank you.

I didn't want to jump in on this one, but now your post has been here for two weeks without a single response. I can just as well give and answer and hope for the more knowledgeable guys to correct me.

Without any warranty, no assumed liability and everything else you can think up for a disclaimer: Here is a formula I made up:

I =10^(3/50 x (35-AWG))

I could explain how I arrived at it, but I don't think anyone is interested nor do I have the time at the moment.

Never saw the post!

Anyway, it's not that simple. Much depends on the insulation and the cable construction just like the larger stuff. Unless you are running uninsulated wire in free air the correct source of information will be the manufacturer.

-Hal

Sorry, I missed this first time round as well.

There are variations in the allowable ampacity depending upon specific conditions, just as the NEC restricts currents for bundling, ambient temperature, etc.

The low-voltage cabling used in marine/automotive applications, for example, often has somewhat higher ratings than for house wiring. Compare the NEC with this table of marine use, for example:
http://www.cmsquick.com/Tech.html

Here's one table of ratings for general equipment use:
http://xtronics.com/reference/wire_gauge-ampacity.htm

20 AWG -> 3.3 Amps
22 AWG -> 2.1 Amps
24 AWG -> 1.3 Amps

Oh ya, almost forgot:

NOTE: This information is provided as is without any express or implied warranties. While effort has been taken to ensure the accuracy of the information contained in this text, the author assumes no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The ampacities listed might be totally inaccurate, inappropriate, or misguided. There is no guarantee as to the suitability of said circuits and information for any purpose.

Jim Sokaloff

Now we have at least four different answers, with a huge spread. There is a reason for this: It makes a difference if it is a network cable with 8 wires or a single wire inside a computer case. You need to derate for bundling, as you can see in Paul's first link. If you have one of those phone cables with dozens of pairs, it must be quite severe.

My little formula above simply approximates 310.16.

[This message has been edited by C-H (edited 11-11-2004).]

According to table 13.5.1 in NFPA79 Electrical Standard for Industrial Machinery.

#24 = 2A
#22 = 3A
#20 = 5A
#18 = 7A

These values apply to both 60 and 75C insulations in ambient 30C.

[This message has been edited by JBD (edited 11-11-2004).]

Thank you guys very much! I ws starting to get worried, but if you missed it, don't worry about it! Thanks again.


[This message has been edited by Theelectrikid (edited 04-23-2005).]