ndinsmore

Waterproof connector for B&G 20/20

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We recently had to cut a B&G 20/20 CD display at the mast, and now need to find a connector that we can use to reconnect the cable.   

It is a shielded 6 wired cable that will need to be waterproof since the only protection it will have is the mast mounting frame which is open on all sides.

In the following thread :  

Moonduster had recommended some connectors from Pheonix.

It looks like they have an 8 wire line that may work.  Phoenix Connector 8-wire

Does anyone have a better recommendation?   does the cable really need to be shielded here or is that just for close confines like in the mast?

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The NMEA 2000 network is sensitive to loads and noise. If your signal level is attenuated to where noise is significant it will have a poor throughput.

Controlling the loads, distance and terminations gives best signal 

Shielding and a proper Star ground help reduce noise. 

Your network will vary.  

Isolating high data rate (AIS) senders (eg on dedicated NMEA0183) can help. 

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 that display had about a 6' cable lead on it to connect to the network - what happened to that connection point? 

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This is a mid-season repair so the mast is already up.    We tried everything we could to get the other end back through the mast, but the cable just didn't want to budge.  

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As a get you sailing quick fix you can try just using any old crimp terminals just to connect the wires together. This includes the shield, pull the strands out and twist it into one strand so you can connect it as well. 

Its a complete bodge, but it worked to keep me going for a couple of days but I've got a pretty small network with short runs.  

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Your 2020 is either a fastnet or nmea2000 device. Either way, it's a five wire bus. Power, return, data+, data-and a shield (red, black, white, green or blue) that's not really required. The connectors mentioned in the other thread are the right connectors.

I'm not familiar with any 2020 that had more cores, although some ffds do. What is the exact label on the device?

 

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best to keep the shield, though it probably won't matter for the short run between connector and display (the shield will not be connected at the display anyway).

 

I would suggest some deutsch automotive-style connectors. Readily available.  You might need to find someone with an appropriate crimper, your local autoelec may have one.

 

https://www.digikey.com/en/product-highlight/t/te-connectivity-deutsch-ict/dtm-series-connectors

 

8-pin..

https://www.digikey.com/product-detail/en/te-connectivity-deutsch-connectors/DTM06-08SB/1734-1065-ND/6566629

https://www.digikey.com/product-detail/en/te-connectivity-deutsch-connectors/DTM04-08PB/1734-1075-ND/6566639

 

If you want something even more rugged: https://www.digikey.com/en/product-highlight/t/te-connectivity-deutsch/hdp20-connectors

 

I'd be wary of using anything like those Phoenix connectors -- the die-cast housings will gunge up in a salt environment.

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The Deutsch connectors you mention won't be water proof at all with the 24AWG cores from the Fastnet or CAN cables - they are only good to 22AWG and they have no cable strain relief. They're entirely the wrong solution in this application.

The phoenix connectors are entirely plastic, require no tools and incorporate cable strain relief. They are a better solution for this application by every measure.

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So I am into the instrument display now and there are a few interesting findings.   First which the cable has 6 conductors really on 5 are used + a shield, the extra relative to the NMEA of fastnet basic wiring is for a remote button to change the display.  

The other interesting thing is that the shielding is attached to the metal housing, also it is connected to the board with a decoupling capacitor to the ground. 

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Ahh, of course, the remote button. Do you use that?

There's not much interesting about connecting the shield to the housing - it's just extending the noise containment provided by the shield. Similarly, connecting the shield to Vss via a cap is a fine treatment. What's important is that there's not a DC connection of the shield at both ends of the cable - when in doubt, no connection to ground is usually a better choice than one at each end.

I wouldn't hesitate to abandon the shield and use those Phoenix M12-5 connectors for the Fastnet + Remote Button signal. However, if you don't use the button, then continuing the shield through the connector makes sense.

There are many other choices of connectors. If you're looking to preserve both the shield and the button we can find some alternatives.

 

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7 hours ago, Moonduster said:

The Deutsch connectors you mention won't be water proof at all with the 24AWG cores from the Fastnet or CAN cables - they are only good to 22AWG and they have no cable strain relief. They're entirely the wrong solution in this application.

The phoenix connectors are entirely plastic, require no tools and incorporate cable strain relief. They are a better solution for this application by every measure.

Moonduster - learn to use the quote button, please.

Ok - 24AWG is a problem for waterproofness.

Strain relief is not an issue. Surely the OP can operate a cable tie, and both the display and lead-in are fixed.

 

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