Consumer-level electrical portable cords come in a variety of types (and gauge, but that's not the subject here) and each must have its rationale, considering the cost constraint (performance/price sweet spot) and environmental use cases (exposure to water/oil/others liquids, abrasion, visibility, temperature...).

I have a hard time finding out a good reference (the most appropriate wikipedia page is poor on pointers) on how these standard cord types came to be, and how a product designer would choose a particular cable type over another.

Typical examples:

  • SVT/SJT cables are used for computer power cords;
  • HPN cables are used in North America on kettles and toasters;
  • I've seen electric irons with cotton-braided cables, I'd expect them to have constraints as kettle cables, plus mobility;
  • lawn mower cords are typically SJTW with flashy colors (not green...);
  • extreme temperature car block heater cables are STOW, it seems that rubber starts to go hard at -40°C
  • household vacuum cleaner cords are often SV (and often at the gauge limit but are pretty long and tend to be used for a few minutes only...) while garage vacuums are using SJTW (also with bigger gauge in my experience);
  • SJOOW seem to be used in construction

1 Answer 1


The choice of cable is down to the environment that the cable is working in.

Designers will be looking at mechanical abuse - by accident or not, temperature, chemical hazards etc.

So, taking your some of your examples: Computer power -assuming you mean desktop little movement ambient temperature low chemical hazard.

Kettles / toasters - temperature risk, kitchen environment so liquid etc

Electric irons the cotton braid was used against temperature risk due to possibility of cable coming into contact with the hot surface.

Lawn mowers cords - visibility is an extra one here many people run over the cable with a mower (how to design for stupidity...)

There is no one design document that I am aware of, the usual process is the designer has to evaluate and mitigate the risks inherent in the situation and also comply with any laws / regulations / codes which is the minimum - also fire departments may have applicable codes and so may insurance companies.

  • $\begingroup$ Allow me to wait and see if someone else has some information, or starts to write that book ;) $\endgroup$ Commented Jun 29, 2017 at 20:27
  • $\begingroup$ "How to design for stupidity" you can never make anything stupid proof, the best you can hope for is stupid-resistant $\endgroup$
    – Diesel
    Commented Dec 14, 2017 at 18:22
  • $\begingroup$ @Diesel "stupid resistant" like it :) The other phrase that works is "you can't make something foolproof as fools are so ingenious"... :) $\endgroup$
    – Solar Mike
    Commented Dec 14, 2017 at 18:38
  • $\begingroup$ @cJZougloub Are you going to accept my answer then? $\endgroup$
    – Solar Mike
    Commented Dec 14, 2017 at 18:38

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