how to find wire amp rating

Discussion in 'The Projects Forum' started by samjesse, Mar 20, 2018.

  1. samjesse

    Thread Starter Senior Member

    Sep 14, 2008
    I have a cable which has 3 wires, each wire is 7 strands of SWG 22.

    I need to find the transmission amp rating for this cable. How do I go about it?

  2. shortbus


    Sep 30, 2009
    Look at the printing on the wire jacket. Any good brand of wire will have the wire gauge either printed or molded into the jacket. The 7 strands of SWG 22, is kind of meaningless, since stranded wire is given in total wire gauge not usually broken down like your saying. Different makers use different numbers of strands to make up their wire gauges.
  3. ebp

    Well-Known Member

    Feb 8, 2018
    7 strands of 22 g is equivalent to about 14 g in cross-sectional area.

    I often say you can put 100 amps through a 30 gauge wire - you just can't do it for very long.

    Current rating for wire depends on how it is to be used and the allowable temperature rise. For example, in North America 14 AWG as an extension cord ("portable cordage") would be rated for up to about 14 amperes, but if the cord were long the recommended maximum current would be lower because of excessive voltage drop. The same conductor size, if run inside a conduit with other similar conductors, would typically be rated for lower current because of higher temperature. If you were to use it for low voltage, either AC or DC, the allowable current would most likely depend on how much voltage drop you could tolerate and be well below the safety rating.
  4. JWHassler

    Active Member

    Sep 25, 2013
  5. DbLoud120

    Active Member

    May 26, 2014