Wire sizing chart

[Jeremy]

Came across this on a boating site and thought I'd be worth posting here as questions about correct wire sizes are asked quite frequently:



Here's the full article: http://www.sailmagazine.com/cruising/cruising-tips/handy-wire-selection-chart/

Jeremy

[Brassman]

Probably best to stay with the NEC for wire. There are some ifs, and buts, in selecting the right wire. Like kind of service, installation, and environment (temp, moisture, sun, etc.).

[DoubleEagle]

Compared to household wiring sizes, that chart seems to be very conservative. You don't have to run very far before the wire size gets upped considerably. Marine standards are different.

[Oonrahnjay]

Probably best to stay with the NEC for wire. There are some ifs, and buts, in selecting the right wire. Like kind of service, installation, and environment (temp, moisture, sun, etc.). 

       Yes, that sounds right to me, and there's the issue of harnessing and the bundling effects that we have - particularly heat from individual wiring wrapped together. 

[Jeremy]

What is NEC? This whole subject is something I don't know much about, but knowing that marine things are tend to be a gold-standard generally my instinct was that using similar specs in a bus conversion would be excellent practice.

Jeremy

[bevans6]

British equivalent of NEC is BS7671.  NEC is the National Electrical Code for buildings in the USA.  Your chart is based on voltage drop and ignores insulation type, core conductor type, in conduit or open air, and a whole bunch of other things, but seems pretty OK to me.  Probably there is fine print about that stuff in the resource material you got it from.  There are many many standards to choose from and they all gravitate towards the same result.  ABYC is the American standard for marine wiring, and there is an equivalent BSI code.

Brian

[Jeremy]

Ok, thanks

Jeremy

[bevans6]

People tend to forget that you and I, and some others, aren't in the USA...   We have to learn to translate sometimes...