Ampacity Table


  • This table is for boat cable with an insulation rating of 105 deg C.  If you have different cable then you need a different table.  If your wire has a higher insulation rating it can carry more current, if the rating is lower it can carry less current.
  • The current carrying capacity of a wire is reduced if it is in the engine room (because it is assumed that the ambient temperature will be higher) and it is also reduced if the wire is part of a large bundle of wires (because it is affected by the heat from adjacent wires)  
  • The concept behind all this is we want to stop the insulation from melting or going on fire, so the ambient temperature matters as does the rating of the insulation.
  • In DC circuits voltage drop becomes an issue and will normally determine the size of wire used. Consult the Voltage Drop Tables for more details
  • Check out our Boat Cable at PKYS using the link below, all the Boat Cable we sell has a 105 deg C insulation rating:


Mike Velys

Date 8/26/2023

Peter Kennedy

Date 8/28/2023

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