44

Why do banana plugs need these holes?

enter image description here

JRE
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Arseniy
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    You can connect another banana plug in one of those holes. – Andrew Morton Sep 07 '20 at 10:25
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    They don't need it, it is a (nice and useful) feature of these particular plugs. – Bimpelrekkie Sep 07 '20 at 10:28
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    They are often called "stackable banana plugs" – andre314 Sep 07 '20 at 10:35
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    @andre314 I think "stackable" specifically refers to the type with a jack that's collinear with the plug; at least that's how I use the term. – Hearth Sep 07 '20 at 11:03
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    I much prefer the 'end stackable' to the 'side stackable' plug that you've illustrated. Once you have several stacked plugs going into the 19 mm (3/4") standard spacing of a meter input, the plug tips sticking through can short to each other, or to other things. With an end stackable plug, the plug tips stay insulated. – Neil_UK Sep 07 '20 at 11:07
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    Yo, dawg. They heard people liked banana plugs, so they put holes in your bana plugs so you can plug a banana plug while you plug a banana plug. – dim Sep 07 '20 at 11:28
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    That choice of wire colours is making me twitch... –  Sep 07 '20 at 12:41
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    @BrianDrummond What's the matter with it? Standard Euro brown for hot, blue for neutral... I'm not helping, am I... – Harper - Reinstate Monica Sep 07 '20 at 18:58
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    @BrianDrummond I have literally had that last week in my motorhome, fitting some USB/lighter sockets. Opened up the cupboard panel on one side, checked the wires with a meter. Brown hot, blue cold, fine. Opened up the cupboard panel on the other side, brown and blue cables again. Cut the cables. Then thankfully I checked with a meter just before I wired them up, instead of making an assumption. Brown cold, blue hot. WTAF?! The same guy wiring a van apparently couldn't even be consistent one day to the next. – Graham Sep 07 '20 at 20:10
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    It's called a bananana plug. – A. I. Breveleri Sep 08 '20 at 04:32
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    @Harper-ReinstateMonica Right, but then why not "red for positive, black for ground" as well? Red on brown and black on blue would make perfect sense. – TooTea Sep 08 '20 at 07:16
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    hence the "I'm not helping, am I" comment @TooTea – JCRM Sep 08 '20 at 10:46
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    Brown phase wire to the black Neutral plug. | Blue Neutral wire to the Red (old code) phase plug. | Go on throttle up! :-( – Russell McMahon Sep 09 '20 at 03:22

2 Answers2

96

Does this banana plug picture help you understand why: -

enter image description here

You can get different variants too: -

enter image description here

And end-stacking types: -

enter image description here

Andy aka
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    With 4 of them and a little skill you can (probably) get a mechanically almost locked 4 wire connection :-). – Russell McMahon Sep 09 '20 at 03:24
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    @RussellMcMahon it is not that difficult actually, it is not actually locked as it might seem. You just make two couples and then mate those. – Vladimir Cravero Sep 09 '20 at 06:33
  • @VladimirCravero Yes - I visualised how to put it together. Past experience (not with banana plugs) suggetss it MAY require "wriggling it all together" . Not hard but sometimes 3 hands needed. I'll try it some time :-) – Russell McMahon Sep 09 '20 at 08:52
  • If you have banana banana cables long enough, you can build yourself a nice pendant. – Vladimir Cravero Sep 09 '20 at 13:01
  • Banana #1 is also known as an insulated banana. The barely visible plastic around the pin helps against accidental short-circuits, particularly useful when working with mains voltage. This particular one probably has a retractable sheet, there are also plugs with fixed sheets. Those are less-stackable but even more safe. – Mast Sep 09 '20 at 13:12
  • I prefer the last position being banana #2 – Sinan Samet Sep 10 '20 at 07:42
  • Nicely explained in picture :) – Liakat Hossain Sep 10 '20 at 11:50
60

Your banana plugs have holes so that the plugs can act as banana jacks.

You plug one banana plug into the plug panel of, say, a power supply. You can then plug another banana plug into the first plug.

It's a helpful feature for making multiple connections with banana plugs.

JRE
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