Wednesday, October 30, 2019

Cable size - AWG to mm2 / Crimping Tools / Cable Selection


In civilized Europe 😇 we (tend to) have more reasonable presidents / prime ministers / monarchs, and we use the metric system. Which makes us happy.

(Two reasons why the United Kingdom is neither civilized nor part of Europe 😅)

Conversion table

What makes us less happy is (smaller) crimping tools typically use AWG indications for cable thickness. One day we'll convince those barbarians metric is better, until then some conversion is required.

(I grabbed this table from the Internet, I hope it's correct. Use at your own risk.)

AWG - mm2

30 - 0.05
28 - 0.08
26 - 0.14
24 - 0.25
22 - 0.34
21 - 0.38
20 - 0.50
18 - 0.75
17 - 1.0
16 - 1.5
14 - 2.5
12 - 4.0
10 - 6.0
8 - 10
6 - 16
4 - 25
2 - 35
1 - 50
1/0 - 55
2/0 - 70
3/0 - 95
4/0 - 120
300MCM - 150
350MCM - 185
500MCM - 240
600MCM - 300
750MCM - 400
1000MCM - 500

Adjust crimping size

Although you should be able to rely on the listed dimensions, you cannot. Unless one spends hundreds / thousands of dollars on professional crimping gear we'll have to settle for cheaper knock-off tools and connectors. For hobby work that's fine.

Unfortunately there's... a. lots of cheap crappy crimping tools out there, and b. sometimes you have to adjust to reality.

For example, if the (clone) connectors are made of thicker material, or the cable is on the higher end of a connector range (for example a pin may be designed to handle 0.5 to 1.5 mm2 cabling, or have an even larger range) you sometimes have to go 'up' a step.

As a rule of thumb: ignore what it says on the tin. Start with the crimping slot which matches your connector, then go up or down if it doesn't crimp well.

It also depends on what you are crimping. What type of connector? What part of the connector? The copper part? The section with the insulation?

  • Different connectors need different kind of crimping tools / beaks
  • Fastin / Faston connector have the the second set of 'wings' forced 'into' the isolation
  • 'Dupont' style of pins have their second set of wings folded around the isolation
  • High current / high reliability connections require professional tools, keep it safe!


Check out these links:



Matt Millman's page which is very informative:

The YTH-202B Matt Millman refers to is also known as the Velleman VTECT2 (actually, there are some differences, but the main beaks are identical):

My knowledge is fairly limited, but that VTECT2 is one weird tool. I wonder if it would be possible to find the original purpose of each and every slot anywhere... Very weird.

Cable selection

Warning! When in doubt consult a professional!

Waarschuwing! In geval van twijfel altijd een professional raadplegen!

Use the following information, links and apps at your own risk! Be careful with electricity, cables which are too thin can and will overheat and can cause fire and other dangerous situations!


Electrical Calculations - Ettore Gallinaone

Electrical Calculations - Hassaan

Links - English

None yet

Links - Dutch


Maximale kabeldikte:

PowerReel verlengkabels:

Nexans EasyCalc:

Kabelberekening volgens NEN1010:


Artecta LED armaturen Tabel:


Every country has different rules, and these may change over the years.

The following notes are for my own use.

Draden per buis in NL

1.5 mm2 versus 2.5 mm2

  • 16A automaat -- 2.5 mm2 blauw / 2.5 mm2 bruin
  • 10A automaat -- 2.5 mm2 blauw / 2.5 mm2 bruin (anders dan in Belgie!)
  • Verlichtings schakelaar (enkelpolig) -- 1.5 mm2 zwart / 2.5 mm2 blauw

2.5 mm2 wordt gebruikt als 'verzameldraad', hierachter bevinden zich meerdere stroomverbruikers, stroomverbruikers achter stopcontacten, en verlichtings eenheden.

Draaddikte is afhankelijk van onder andere lengte, temperatuur, maximale spanningsval enzovoorts. Om de installatie te vereenvoudigen zijn de draad diktes voor reguliere huis installaties in de NEN1010 vastgelegd.

2.5 mm2 is inderdaad theoretisch overbemeten, 1.5 mm2 is voldoende voor 16A / 50 meter kabel lengte / 2% spanningsval. Voor de veiligheid is echter 2.5 mm2 voorgeschreven voor alles behalve verlichtingsbedrading.

Schakelmateriaal in NL is max 10A. Regulier schakelmateriaal mag NIET gebruikt worden om stopcontacten mee te schakelen.

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