How can the current carrying capacity of copper filled via through an alumina ceramic be measured?

Answer 1

This depends on whether the wire is copper or aluminum. In aluminum, you need to go UP one wire size to carry the same amount of electricity, because copper is a better conductor than aluminum. The normal ratings are as follows for the most common wire sizes in houses

Copper

14 gauge=15 amps

12 gauge=20 amps

10 gauge=30 amps

8 gauge= 40 amps

6 gauge= 50 amps

and so on. it goes all the way to a 2/0 which will carry 200amps

In aluminum you step up a size, as in

12 gauge= 15 amp

10 gauge=20 amps

and it would take a size 4/0 aluminum to rate at 200 amps, which is pretty much the standard household amperage requirement in most places in the US

Answer 2

There are two questions here. The current carrying capacity of copper wire is determined by a table in the electrical code book. This book is compiled by safety experts and research institutes to determine how much current can be carried by a wire before the insulation melts off. A safety factor is added in and then the size of the wire for a particular current is determined and published. Current flowing in a wire can be measured with an amp meter. The most used amp meter used by electricians is a called a clamp on amp meter. It is a type of transformer that clamps around the wire that is being tested. The current flowing through the wire induces a current into the meters receiving coil and gives a direct readout on the meter face. This readout is calibrated to correspond with the exact current flowing in the wire. The nice part of testing current this way is that the circuit does not have to be opened to insert a series type amp meter.

Answer 3

The same way any conductor's rating can be determined...

You pass current through it until the desired limit for voltage drop, and thus power and temperature, is exceeded. You then apply a safety factor so as to minimize the risk of fire and performance degradation.

If you want to know this a priori, consult a table, such as what is included in the National Electrical Code.

Answer 4

Current capacities of wires are normally not calculated. An electrician would normally refer to the allowable ampacities of wires in the (2011) NEC Table 310.15(B)(series) and 310.60(C)(series). Ampacity ratings are provided for a number of situations.

If you want to use that math used to derive the figures for the tables...

The current carrying capacity (in amps):

I = 106 x D2/700

(cross-sectional area is 700 mils per amp)