Shielded Signal Cable At Top Of Mast

[Jokani]

I am fitting a new wind transducer at the top of the mast - it uses a shielded cable, which I understand is important - to be able to route the cable inside a conduit, I need to cut the cable and rejoin it - I intend to do this inside a weather-resistant electrical box fitted on top of the mast head.

My question is - Do I need to add back some shielding around the connectors, or will not having shielding around the connectors make little/no difference? There will be other cables carrying 12v + and - inside the same box?

TIA

 

[Boathook]

Can't you get the joint inside the boat ? Not to sure why you need to cut the cable near the transducer.

 

[MontyMariner]

I intend to do this inside a weather-resistant electrical box fitted on top of the mast

Not a good idea. Measure length down to below deck (through deck gland) and cut there so the junction box can be mounted on a bulkhead.

 

[vyv_cox]

Not a good idea. Measure length down to below deck (through deck gland) and cut there so the junction box can be mounted on a bulkhead.

Exactly what I did. Junction box on the heads wall beneath the mast.

 

[Dockhead]

Not a good idea. Measure length down to below deck (through deck gland) and cut there so the junction box can be mounted on a bulkhead.

I agree, but that's not responsive to the OP's question.

He's not asking whether he should do it, but how.

 

[Dockhead]

I am fitting a new wind transducer at the top of the mast - it uses a shielded cable, which I understand is important - to be able to route the cable inside a conduit, I need to cut the cable and rejoin it - I intend to do this inside a weather-resistant electrical box fitted on top of the mast head.

My question is - Do I need to add back some shielding around the connectors, or will not having shielding around the connectors make little/no difference? There will be other cables carrying 12v + and - inside the same box?

TIA

Use a shielded/EMC waterproof junction box with EMC cable glands, and this question won't arise.

If you can't find one of those and have to use a normal junction box, this won't defeat the shielding. The shielding is intended to inhibit capacitive and inductive coupling operating over lengths of cable. A small bit of unshielded cable won't couple that much.

HOWEVER, in any case, make sure the shielding is properly terminated, and don't use long pigtails.

As others have written, you would really prefer not to have a junction box up the mast, if there is any way to avoid it. Why wouldn't you just pull the cable DOWN through the conduit? If the problem is a plug or other termination at the boat end of the cable, I would much rather cut that off at the lower end and either use a field connect plug or do the junction box below.

Is it an NMEA0183 cable, NMEA2000, or pulse/analogue? What kind of ducer?

 

[neil_s]

I cut my wind transducer cable at the top of the mast so that I could dismount the transducer for safe keeping over winter. I used a Bulgin Buccaneer water proof connector to re-make the joint. The cable screen was simply routed via one of the connector pins. There is a similar connector pair at the base of the mast. The wind instrument is one of NASA's older five wire analogue models and works reliably despite the two cable breaks!

 

[Jokani]

Thanks for all the helpful comments.

The cable is 0183 and the transducer is a LCJ Capteurs CV7 - I took a picture at the weekend, not very tidy but I'm confident it will be robust.:



I think I will leave the cable as it is, uncut, and just hide the excess in a piece of cable cover. This will not be as tidy, but does mean I will not have to cut the cable at this time.

If I need to remove it at any time in the future, then I can cut the cable and use the above advice to reconnect.