Two round pin 12v socket

[Stuart_]

Hi,

 

I've just purchased a 2007 narrowboat that has 2 round pin 2v sockets. Has anyone come across these before and can point me to corresponding plugs. Also, what type of 12v socket is now standard?

 

Thanks

 

Stu

[Guest]

19 minutes ago, Stuart_ said:

Hi,

 

I've just purchased a 2007 narrowboat that has 2 round pin 2v sockets. Has anyone come across these before and can point me to corresponding plugs. Also, what type of 12v socket is now standard?

 

Thanks

 

Stu

 

Very common on caravans at one time. I've fitted them in the past. That one is obviously to supply a 12v TV.

 

You may still be able to get the correct plug from a caravan accessory place or eBay.

 

Oh and welcome to the forum.

[Jen-in-Wellies]

32 minutes ago, Stuart_ said:

what type of 12v socket is now standard?

There is no standard. The car accessory style plug/socket is common, though they are limited in current carrying capacity without melting. Various two and three pin mains styles are repurposed by some. Important that a 12V plug cannot fit in any mains socket on the boat and visa versa.

Welcome to the forum by the way.

[David Mack]

You could use a flat pin plug in that socket. This may fit.

https://camperselect.co.uk/product/w4-clipsal-type-2-pin-12v-plug/

[Nightwatch]

That’s the system we have on Nightwatch. We get on alright with it and sockets and plugs readily available.

[Tracy D'arth]

That socket will accept a 2 pin BS546 plug, a european Schuko plug or an American style 2 pin flat blade plug.

[truckcab79]

Sorry for the slight hijack but similar question been on my mind while planning mine.  Does stuff like Tv / fridge / laptop charger / other 12v stuff come with a standard plug or are they generally sold bare-wired or with  a car-accessory type plug which people then cut off and replace with something better.  

[jonathanA]

depends @truckcab79 most 'boat stuff' like fridges  or pumps come with bare wires or connectors for your bare ended wires. most 'Car accessory' stuff like laptop chargers will most times have 'cigarette lighter' type plugs which you can either use (not very reliable) or cut off and fit your own.  of course a lot of stuff comes with USB charging these days so having some USB charging points is probably increasingly worthwhile. 

 

if i was starting from scratch i would use round pin mains plugs and sockets (2A/5A) for anything 'portable' (and 12V) as they are readily available, properly designed and economically priced. 

[Guest]

44 minutes ago, Tracy D'arth said:

2 pin BS546 plug

 

Are they not only three not two pin though??

 

 

Edited December 5, 2023 by M_JG

[magnetman]

Another one worth considering if building from scratch is Hella plugs and sockets. They are quite good, very low profile and impossible to mistake for something else. 

 

I once had a narrow boat where the 12v cabin accessory sockets were Square pin 13a domestic type. On the 12v circuit! Nuts ! 

 

5A looks quite nice in boats. 2A is a bit fiddly. 

Don't forget USB sockets as well. So many things these days either need or can be run on USB. Including my christmas lights. 

 

 

[alan_fincher]

Unless I'm missing something a plug to fit that socket can go in either of 2 ways around.

If you are connecting something where polarity is important it looks like you could easily end up with positive connected to negative, and negative connected to positive.

 

If polarity is the wrong way around then you could end up destroying the equipment involved, unless it has circuitry to guard against wrong polarity.

[Guest]

16 minutes ago, alan_fincher said:

Unless I'm missing something a plug to fit that socket can go in either of 2 ways around.

If you are connecting something where polarity is important it looks like you could easily end up with positive connected to negative, and negative connected to positive.

 

If polarity is the wrong way around then you could end up destroying the equipment involved, unless it has circuitry to guard against wrong polarity.

 

True. But still very common in older 12v systems in caravans which looks like where that originates. I can't recall us ever having an issue as we used them a lot 'back in the day' for our telly's.

 

You don't see them any longer as modern caravans tend to use the cigarette lighter type sockets for 12v, unless an owner has carried out a mod to fit or add one.

 

 

Edited December 5, 2023 by M_JG

[Tracy D'arth]

1 hour ago, M_JG said:

 

Are they not only three not two pin though??

 

 

The pin spacing is different between the 3 and the 2 pin BS546 plugs, the 2 pins are slightly closer together.

I have a technique for using 13A plugs for low voltage that works and is fail save, I picked it up from a serious old boater, perhaps he built your boat?

[GUMPY]

3 hours ago, Tracy D'arth said:

That socket will accept a 2 pin BS546 plug, a european Schuko plug or an American style 2 pin flat blade plug.

The blades are not the same size on the caravan sockets so USA plugs may not fit properly.

 

 

1 hour ago, alan_fincher said:

Unless I'm missing something a plug to fit that socket can go in either of 2 ways around.

You are🤔 The flat blades on the caravan plug are different widths so cannot be reversed

 

Edited December 5, 2023 by GUMPY
Add pic

[magnetman]

Clever ! 

 

 

 

Of course if one did want to use square pin 13A plugs and sockets you could just use the earth pin for the negative. 

 

 

 

Bang? 

[GUMPY]

 I took all the 12v sockets out of my boat and replaced them with 18watt USB sockets as most stuff needs USB to charge rather than 12v.

I have a couple of 12v 2.1mm trailing cables in the caravan to run the TV/Soundbar that are 12v, other than that it's the same usb sockets.

[magnetman]

I've used the surface mount type. They are actually pretty good. Better than I expected. 

 

 

 

 

I am sure they were more like £5 than £10 though .. 

The light bar is a bit bright. 

[Guest]

22 minutes ago, GUMPY said:

The blades are not the same size on the caravan sockets so USA plugs may not fit properly.

 

 

You are🤔 The flat blades on the caravan plug are different widths so cannot be reversed

 

 

Ah yes. That takes me back 40 years!

[GUMPY]

27 minutes ago, M_JG said:

 

Ah yes. That takes me back 40 years!

Not that long, my 2001 Sterling Europa had Clipsal sockets as standard fitment.

[Guest]

1 minute ago, GUMPY said:

Not that long, my 2001 Sterling Europa had Clipsal sockets as standard fitment.

 

I recall fitting them to my 1984 Sprite Alpine.

 

 

[Stuart_]

Many thanks for the feedback, and the help :)

 

Stu

[Ronaldo47]

I understand that the present US recommendation is for one pin to be larger than the other to provide their 2 pin plugs with  polarisation, but all of the ones I have come across fitted to imported equipment manufactured in the Far East,  have had two identical pins. 

[wakey_wake]

Yes, there's no standard and most of the options have problems.

Mine came with a couple of cigarette lighter sockets and a fair fitout of W4 sockets.

 

The cig lighter is IMO a horrible plug. It has minimal wiggle-out protection and so it's prone to come loose, then it can just switch off or worse overheat at the slack contact. We don't use the hot element (actual cig lighter) part any more, so why use the rest of the form factor?

Thanks for the links to better quality ones - another thread - I'm just happier without them.

 

The W4 isn't bad, and can carry more current. Mine claim to be rated for 10A, and when new they're probably good for that. The springs can get loose over time and then maybe they'll overheat at 10A also? I would rather not find out because nothing in the design prevents an overheat running away to fire. Also I didn't want to set out out with a whole new kit of four-ways and extension cables in a new standard.

 

Anyway is it practical to draw more than 5A on a 12V socket. a) I have very few devices that would try, and b) unless the cable was chosen with that in mind then voltage drop stop a heavy-current device working properly.

 

Therefore I concluded that the assortment of lower power 12V devices I have can run off 2.1mm barrel connectors, for which the CCTV industry provides cheap connectors. Be sure to have a insulated tip on the inner positive, and if buying pigtail connectors check the cable size - some are really thin cheap junk.

 

On 05/12/2023 at 17:58, GUMPY said:

 I took all the 12v sockets out of my boat and replaced them with 18watt USB sockets as most stuff needs USB to charge rather than 12v.

I have a couple of 12v 2.1mm trailing cables in the caravan to run the TV/Soundbar that are 12v, other than that it's the same usb sockets.

The USB PD standard is quite flexible in this respect, and I considered something similar. You can also get "USB PD spoof" boards which will request that the USB PD socket provide 5V, 9V, 12V or various levels between. These could be useful for other kit, but you would need to ensure it remembers the correct setting.

 

However each socket will have an idle current draw, which might be insignificant in your power budget but it bugs me; and you can't (in some cases shouldn't) put a splitter after the USB PD output, because the devices may want different voltages, so it makes sense to over-supply with USB sockets.

 

[GUMPY]

8 hours ago, wakey_wake said:

 

However each socket will have an idle current draw, which might be insignificant in your power budget but it bugs me; and you can't (in some cases shouldn't) put a splitter after the USB PD output, because the devices may want different voltages, so it makes sense to over-supply with USB sockets.

There is no current draw on any of my USB sockets when they are not in use. Each one has a revolutionary device in line called an on/off switch so they are switched off when not in use.

[Puffling]

9 hours ago, wakey_wake said:

Yes, there's no standard and most of the options have problems.

Mine came with a couple of cigarette lighter sockets and a fair fitout of W4 sockets.

 

The cig lighter is IMO a horrible plug. It has minimal wiggle-out protection and so it's prone to come loose, then it can just switch off or worse overheat at the slack contact. We don't use the hot element (actual cig lighter) part any more, so why use the rest of the form factor?

Thanks for the links to better quality ones - another thread - I'm just happier without them.

 

The W4 isn't bad, and can carry more current. Mine claim to be rated for 10A, and when new they're probably good for that. The springs can get loose over time and then maybe they'll overheat at 10A also? I would rather not find out because nothing in the design prevents an overheat running away to fire. Also I didn't want to set out out with a whole new kit of four-ways and extension cables in a new standard.

 

Anyway is it practical to draw more than 5A on a 12V socket. a) I have very few devices that would try, and b) unless the cable was chosen with that in mind then voltage drop stop a heavy-current device working properly.

 

Therefore I concluded that the assortment of lower power 12V devices I have can run off 2.1mm barrel connectors, for which the CCTV industry provides cheap connectors. Be sure to have a insulated tip on the inner positive, and if buying pigtail connectors check the cable size - some are really thin cheap junk.

 

The USB PD standard is quite flexible in this respect, and I considered something similar. You can also get "USB PD spoof" boards which will request that the USB PD socket provide 5V, 9V, 12V or various levels between. These could be useful for other kit, but you would need to ensure it remembers the correct setting.

 

However each socket will have an idle current draw, which might be insignificant in your power budget but it bugs me; and you can't (in some cases shouldn't) put a splitter after the USB PD output, because the devices may want different voltages, so it makes sense to over-supply with USB sockets.

 

The cigar lighter socket design is indeed vile, and plugs have such variable quality in manufacture that the crucial contact pieces are an unknown.

 

I've drawn 25A over a few minutes from my 12v sockets, slightly above their rating. I regularly use them with a portable inverter drawing 15A without them appearing to warm. But I installed better ones.

 

Edited December 15, 2023 by Puffling