Diameter vs current rate of a copper wire

In summary, if you are doing any electrical work in a dwelling, you will need to get the applicable permits and inspections. If you are caught doing work without the permits or inspections, you may be liable for any damages or injuries that may occur.
  • #1
pixel01
688
1
Hi all,

I am planning some electrical installation in my home and I am not sure about the norminal current that the wire can tolerate. can any give me the ref table or some link of that, I mean for certain diameter (mm), the wire can bear a current (amp).

Thanks
 
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  • #2
This table agrees with what I've read elsewhere, and I believe it's for continuous current with air-cooling (though it uses AWG--American Wire Gauge--which is good, since it's how the wiring is sold at the Hardware store!):
http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity#House_Wiring

If you go down to your local hardware store, you can probably pick up a book that covers this and offers tips on planning your project, and how to install / renovate / replace various things (e.g. Black and Decker Guide to Home Wiring).

If you're doing a fair bit of stuff, I would also strongly recommend you find out what electrical regulations apply in your jurisdiction (i.e. what you can do, and what has to be left to an electrician), and pick up a copy of the abridged code book, which often comes in pretty handy for standard wiring tasks. Far too many people just go cowboy on this stuff, and end up paying for it later.
 
  • #3
pixel01 said:
Hi all,

I am planning some electrical installation in my home and I am not sure about the norminal current that the wire can tolerate. can any give me the ref table or some link of that, I mean for certain diameter (mm), the wire can bear a current (amp).

Thanks

MATLAB beat me to most of this, but I still need to point out -- modifying these things in a dwelling generally requires permits and inspections by your city code enforcement department:

Plumbing, Electrical, Structural.

They are usually pretty helpful linking you up with the applicable local codes (and the NEC in this case). You should not be thinking of taking advice from a web forum and doing this work yourself without getting the applicable permits, and having your work inspected and signed off by the city.

Beyond the common-sense aspects involved, when you go to sell the dwelling, you will be asked if you did any of the above kinds of work to the home, and if you had the applicable permits. If you lie, and you are found out (pretty easy), that can do all kinds of bad things to the sales process. Also, if there is a fire in the dwelling after you do work without permits and inspections, guess who is liable for the damage and any injuries?

Even using licensed contractors, I've caught a couple trying to do work without getting the permits, and I've caught them doing things that would have been dangerous because they weren't obeying the local codes and the NEC. Like overloading circuits, and running too-small gauge wire too far...
 
  • #4
Thank you both for the help. I will look for the regulations as well.
 

1. What is the relationship between the diameter of a copper wire and its current rate?

The diameter of a copper wire has a direct relationship with its current rate. This means that as the diameter of the wire increases, the current rate also increases.

2. How does the current rate of a copper wire change as its diameter increases?

The current rate of a copper wire increases as its diameter increases. This is because a larger diameter allows more space for electrons to flow through, resulting in a higher current rate.

3. Is there a limit to how much the current rate can increase with the diameter of a copper wire?

Yes, there is a limit to how much the current rate can increase with the diameter of a copper wire. This is because as the diameter increases, the resistance of the wire decreases, allowing more current to flow. However, at a certain point, the resistance will be so low that increasing the diameter will not have a significant impact on the current rate.

4. How does the material of the wire affect the relationship between diameter and current rate?

The material of the wire does not significantly affect the relationship between diameter and current rate. However, different materials may have slightly different resistance values, which can impact the current rate at a given diameter.

5. Does the length of the copper wire also affect the current rate?

Yes, the length of the copper wire also affects the current rate. The longer the wire, the higher the resistance, which in turn affects the current rate. This is why thicker wires are often used for longer distances to maintain a higher current rate.

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