Backup heat source for a soldering iron - Page 1
Forum section: electronics / general

author: 5U4GB
author_rank: Super Contributor
timestamp: April 06, 2025, 08:36:27 am
content: It's actually a heat-setting iron for brass inserts, but really just a modded soldering iron. Anyway, who would have thought you can get mains flex in 28AWG?And since it's CCS to boot, if the iron ever fails you can use the wire as your heat source.

author: tooki
author_rank: Super Contributor
timestamp: April 06, 2025, 10:31:57 am
content: I don’t actually see a problem from an electrical standpoint. Well, consider that traditional miniature Christmas lights also used hair-thin wire perfectly safely. The thickness needed for the conductor of a wire is determined by the current (and current-related effects like voltage drop and self-heating), while the insulation is determined by the voltage (and thermal/mechanical requirements). So if you’re only drawing a tiny current, there’s no need for thick mains cable. Your fire stick there is what, 30-40W? So you’re looking at under 200mA at 230V. You couldalmostrun that current through a singlestrandof that CCS wire. (I mean… for pure copper, a single strand of 34AWG/0.02mm2wire can do the needed 180mA while staying within the 60C of normal cable. So 7 strands of CCS of some sort are more than enough. If it actually is 28AWG, then that’s 7x36AWG. 28AWG copper is rated for 0.8A at 60C, FYI.)The only thing that is advisable when using wire too thin to carry a short-circuit current sufficient to trip the breaker is to add a fuse (as Christmas lights do).

author: golden_labels
author_rank: Super Contributor
timestamp: April 14, 2025, 01:58:52 am
content: Thinner wire, stranded or not, is also more flexible and less vulnerable to breaking. So by itself it’s not a sign of poor quality. Check wires on hairdryers and you’ll discover they’re often a bit undersized, despite carrying up to 2 kW. For something running for a few minutes, overheating isn’t an issue.It’s also cheaper, and there is no need to associate “cheaper” with “worse.” There is no virtue in wasting resources, when they buy nothing. If things are overoptimized to save fractions of a penny in every possible place, to the point of leaving no safety margins, then it’s a bad design. But otherwise it’s reasonable engineering.BTW, how are your abacus skills?

author: Kean
author_rank: Unknown
timestamp: April 14, 2025, 02:42:53 am
content: Quote from: 5U4GB on April 06, 2025, 08:36:27 amIf it is permanently attached to the equipment and meet the current rating, then it seems OK. I do wonder what fuse they would include when they are made with a UK fused plug.A bigger concern is that I've seen a few IEC C13 power cable with similar fine stranded CCS and quite thick insulation. These power cables get swapped between equipment frequently. Even if the cable is labelled for a lower current, almost no one would ever read that - especially the tiny molded markings on the C13.

author: 5U4GB
author_rank: Super Contributor
timestamp: April 14, 2025, 03:36:39 am
content: Quote from: golden_labels on April 14, 2025, 01:58:52 amIt was a subtle way of indicating the source of the item in question, in case it wasn't immediately obvious anyway :-). Abacus skills are so-so, mostly caused by the use of literal word-for-word translation in the book, leading to instructions like "cancel the six, forward two" and "two by three is six plus two", so you need to reverse-engineer the rules from the worked text examples (there are no illustrations).