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Best connectors for joining multicores


Stuart91

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I've been asked to help tidy up some wiring in an installation, which was put in many years ago by a volunteer. Most of it is fairly straightforward but there is one piece that's causing a bit of a headache. Basically, someone has run two 16 pair multicore cables from behind wallplates up to a point in the attic space, where they are joined onto a 32 pair cable for the main run to the mix position at the back of the room.

 

This is currently done with chocky block, which looks ratty and is vulnerable to knocks. They'd like it replaced with something tidier and more durable. I know there are various solutions available but not 100% sure what's going to be the best for this kind of application. The cable itself is Canford FSJ series which is certainly decent enough quality. Someone involved with the project seems very keen on some crimped connectors that sound similar to the ScotchLock ones used in the automotive trade. I'm dubious about the idea but can't get any details from him about them, I suspect the main attraction is that he has managed to get a bunch from his day job.

 

We are only needing a permanent connection, there is not going to be any patching or changing of connections, it is literally just a case of joining the cables neatly and cleanly in a way that won't compromise the signal path. I'm open to any ideas that will do the job well, and I wouldn't mind having to spend a little bit of money on, say, a specialised crimp tool, because I imagine it's the kind of thing that could come in handy in future.

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Can't help but feel a telecoms style IDC panel would be the tidiest solution but not sure how well the IDC terminals will connect to the drain wire - what with that being uninsulated.

 

http://m.comms-express.com/products/251a-boxcon-50-pairs-connection-box/

 

Another alternative is jelly crimps, but again not sure how well they will terminate on the drain wire and it will probably be just as much of a mess as chocblock, just smaller.

 

https://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Jelly_Crimp/index.html

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Big adaptable box, three cables entering through suitable glands.

 

Fix either choc block or solder tag strips to the base and connect everything up. Solder strip with Hellerman sleeves would be my preference.

 

You might want to put in some lacing bars out of 5mm studding to keep things really neat.

 

The box will stop the junctions being knocked especially if they are in an out of the way place like an attic.

 

Just make sure the box is big enough to work in neatly and tidily. Label everything so if none of the current team are around, future engineers can work out what has been done.

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krone blocks with sleeving on the drain?

 

 

The thing with Krone blocks is that they are only really meant to be used with solid conductors.

 

Although having said that I've used 1000s at a time in installs with no problems.

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I've done plenty of Krone blocks with FST but the drains were commoned behind the block with Hellerman sleeves and a bit of green wire to a separate "earth Krone"

 

I can't help thinking that this particular installation needs a pair of EDAC connectors and a lot a patience!

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I can't help thinking that this particular installation needs a pair of EDAC connectors and a lot a patience!

 

Not sure how that would work with the 2 x 16 -> 32 configuration, though, unless you're thinking of both 16s running into a single EDAC connector on one side?

 

Regardless of the connectors used, the thing I'd want to achieve most of all is getting this lot into a box with glands on the cables. That'd protect it all much better from knocks and stop it getting covered with "loft crud".

 

Once boxed up, I'd be rather agnostic about connectors. Even choc-bloc wouldn't look so bad if fixed inside the box in an organised manner - though I agree that there are "better" (and more costly) solutions available.

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Not sure how that would work with the 2 x 16 -> 32 configuration, though, unless you're thinking of both 16s running into a single EDAC connector on one side?

 

Either that or two pairs of connectors with the 32 pair split into bundles of 16 with an overall heatshrink. FSJ stands for Foil Screened Jacketed so the pairs are fairly robust.

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Thanks for all the replies.

 

I agree that the most important thing will be getting it all inside a decent sized box, out of sight and away from knocks. I suspect that the biggest problem at the moment is people seeing the rats nest of cabling and chocky block and getting concerned. It's clearly been rankling them for a while.

 

I think I prefer the idea of having connection blocks fixed down onto the enclosure - like the DIN-mounted Wago style, or Krone punch downs fixed in properly. Certainly the Wagos look like an easy solution, although it'll take up quite a bit of space.

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Certainly the Wagos look like an easy solution, although it'll take up quite a bit of space.

 

2000 series aren`t too bad , only 3.5mm wide narrower than choc bloc, similar density to Krone ,shorting bars available to common up multiple terminals. Not cost prohibitive

 

http://uk.farnell.com/wago/2000-1201/terminal-block-din-rail-2pos-10awg/dp/1869247#ProductAccessories

 

Mention of attic space made me think of Wago, massive advantage to no grub screws or hot iron in roof space.

 

Hang on is this Glasgow.... listed building accident with hot appliannce in roof space...loss to fire of listed building leaving cleared block for redevelopment...could be a specialisation there ;-)

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I've got a Farnell account so that's certainly a convenient option.

 

The attic space itself isn't too horrible - it's a modern building and there's a reasonable amount of space. It doesn't look like there are any major fire hazards but it's still better to not be guddling around with a soldering iron.

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+1 for the Wago spring terminals. No screws to work loose, no maintenance required unless there is visually apparent damage. I'm not familiar with the current range of terminals available, but you should be able to get 'double decker' terminals for use where space is tight. If you have not used them before, make sure to practice with some scrap wire on a bench just to get used to using them before heading off to a poorly lit cramped glory hole.... They are a bit different to use compared to choc-blocks or 'normal' din-rail terminals.
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I have seen a product used before where there are 'pegs' (for want of a better phrase) that allow you to solder the wire onto each end. These are then stacked with a spacer, typically three pegs high/deep, with each layer being one of the three cores. It's a nice system, and I thought they were last bought by a colleague from Kelsey, but I can't seem to find them on there, or anywhere else...
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