# ­xkcd thread **URL:** \ **Category:** Cafe Society\ **Tags:** comic-strips\ **Created:** [May 28, 2020, 12:57am UTC](https://boards.straightdope.com/t/xkcd-thread/854574 "2020-05-28T00:57:03Z")\ **Posts on this page:** 20\ **Page:** 284
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [March 10, 2026, 7:20pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5663 "2026-03-10T19:20:20Z")
> [@Lumpy](#): > > A search on 500 Amp cables reveals that they’re commonly sold as jumper cables for starting heavy trucks. We had several 400-amp three-phase cables for shore power on my submarine. As I recall, each cable weighed about 10 pounds per foot. It took a working party to move them. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 10, 2026, 9:03pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5664 "2026-03-10T21:03:46Z")
> [@robby](#): > > We had several 400-amp three-phase cables for shore power on my submarine. At first, I read that as “for short power”. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [March 11, 2026, 1:06am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5665 "2026-03-11T01:06:48Z")
> [@robby](#): > > As I recall, each cable weighed about 10 pounds per foot. Sounds about right. 400A requires 600 kcmil copper (1" diameter) which is about 3 pounds per foot - so 9 pounds just for the main conductors. Add is a safety ground, insulation (what voltage was that at?), and protective cladding and you’re likely over 10 pounds. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [March 11, 2026, 4:02am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5666 "2026-03-11T04:02:50Z")
> [@Marvin\_the\_Martian](#): > > > [@robby](#): > > > > As I recall, each cable weighed about 10 pounds per foot. > > Sounds about right. 400A requires 600 kcmil copper (1" diameter) which is about 3 pounds per foot - so 9 pounds just for the main conductors. Add is a safety ground, insulation (what voltage was that at?), and protective cladding and you’re likely over 10 pounds. Glad my memory checks out! It was 450 VAC. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 11, 2026, 3:54pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5667 "2026-03-11T15:54:37Z")
Well I don’t know what to tell you; a search on 400 amp jumper cables returns plenty of examples that are nowhere near being foot-thick. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [March 11, 2026, 4:01pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5668 "2026-03-11T16:01:03Z")
The double tick " is inches (or seconds if you are talking lat/lon) So 1 inch diameter cable. Brian ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [March 11, 2026, 4:07pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5669 "2026-03-11T16:07:01Z")
> [@Lumpy](#): > > Well I don’t know what to tell you; a search on 400 amp jumper cables returns plenty of examples that are nowhere near being foot-thick. The shore power cables being discussed each contained _three (3)_ 400-amp conductors to carry three-phase AC current. Each conductor was about 1” (one inch) in diameter. The whole cable weighed about 10 pounds per linear foot of cable length (so 10 feet of cable weighed about 100 pounds). Nobody said the cables were a foot thick. With the insulation and protective cladding, the whole cable was actually about 3-4 inches in diameter. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 11, 2026, 4:12pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5670 "2026-03-11T16:12:29Z")
Sorry; my vision is getting THAT bad. ---
**Author:** ![abcdefghij](https://avatars.discourse-cdn.com/v4/letter/a/43a26b/32.png) [@abcdefghij](https://boards.straightdope.com/u/abcdefghij)\ **Post date:** [March 11, 2026, 4:50pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5671 "2026-03-11T16:50:26Z")
> [@N9IWP](#): > > The double tick " is inches “Forget this! Fuck the napkin!” [![](https://i.ytimg.com/vi/zg5Ovdu6bOE/hqdefault.jpg "Spinal Tap - Stonehenge, funniest clip ever.") ](https://www.youtube.com/watch?v=zg5Ovdu6bOE) ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 12, 2026, 3:10am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5672 "2026-03-12T03:10:40Z")
> **[Subduction Retrieval](https://xkcd.com/3218/)** [![](https://imgs.xkcd.com/comics/subduction_retrieval.png) ](https://imgs.xkcd.com/comics/subduction_retrieval.png) “Aww, the oceanic crust and the continental crust are getting married!” ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 12, 2026, 2:33pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5673 "2026-03-12T14:33:43Z")
I’m thinking about the tsunami it’ll trigger if their lifting tackle parts and the crust retreats to its resting state almost instantly. Gonna be epic. Epic fail. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [March 12, 2026, 3:06pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5674 "2026-03-12T15:06:24Z")
And so it was that the one ring came back to the surface once more, and the cycle began anew. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [March 12, 2026, 3:16pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5675 "2026-03-12T15:16:09Z")
Who says geology is not a practical science? ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [March 12, 2026, 4:03pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5676 "2026-03-12T16:03:59Z")
**Data:** I know of no one who said that, Professor. ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [March 12, 2026, 4:53pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5677 "2026-03-12T16:53:17Z")
Fuck ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 12, 2026, 5:18pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5678 "2026-03-12T17:18:12Z")
> [@Frodo](#): > > Fuck. You up for another trip to Mt Doom? ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [March 12, 2026, 5:20pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5679 "2026-03-12T17:20:11Z")
This time I’ll take the bus. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [March 12, 2026, 6:13pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5680 "2026-03-12T18:13:19Z")
Maybe take an eagle… ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 12, 2026, 7:38pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5681 "2026-03-12T19:38:07Z")
> [@Marvin\_the\_Martian](#): > > an eagle Also known as the Deus ex Machina Airlines. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 12, 2026, 7:48pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5682 "2026-03-12T19:48:42Z")
> [@Pardel-Lux](#): > > And so it was that the one ring came back to the surface once more, and the cycle began anew. Yeah, definitely shades of LotR. [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=283) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=285)