Rewiring the mast

[zoidberg]

I have that job to do.

On another forum, there's the suggestion of running 4 or 5 Positive cables ( as needed ) up the mast, with but ONE Negative return.... instead of 'twinned' cabling. All tinned, of course.
Thoughts?

 

[LittleSister]

The downside is a fault on the one negative wire leaves you with no lights at all.

Otherwise, provided the negative wire is sized to handle the current of all lights you might have on at the same time without excessive voltage drop, I don't see why not.

 

[john_morris_uk]

Just how many cables are we looking at and where do they exit? Most masts I’ve played with have three core to the top for the Tri-White and two core going to the steaming light and two core to the spreader lights. (Or three core if it’s a combined deck/steaming light)
Although you could common all those grounds or negatives, how are you going to effect the joins inside the mast to ‘T’ off at each height the various fittings are. It’s more effort than it’s worth and joins/connections are the source of most problems so I’m not convinced of any benefit.
The problem with having a fault in this one common line killing all your mast electrics has already been mentioned.

 

[sarabande]

While you have the mast on trestles, Zoidberg, what about running a thick copper welding cable down from the top, and rigging up a lightning conductor and dispersion system exiting from the base of the mast ?

 

[geem]

A single negative is not a great idea. You need multiple connections to it. How do you do this? Connections inside the mast? Far simpler to run tinned pairs to each device. Not connections other than at the device. independence of each fitting as well.
Installing a conductor is fine but to do lightning protection properly the biggest issue is how the current escapes to the surface of the sea. Copper busbar installed around the hull 300mm below the waterline then wired to the vertical conductor seems to be the best way. Making all that work is fine in a new boat. A nightmare in an existing boat

 

[PaulRainbow]

Just how many cables are we looking at and where do they exit? Most masts I’ve played with have three core to the top for the Tri-White and two core going to the steaming light and two core to the spreader lights. (Or three core if it’s a combined deck/steaming light)
Although you could common all those grounds or negatives, how are you going to effect the joins inside the mast to ‘T’ off at each height the various fittings are. It’s more effort than it’s worth and joins/connections are the source of most problems so I’m not convinced of any benefit.
The problem with having a fault in this one common line killing all your mast electrics has already been mentioned.

I could not have put it better

 

[davidmh]

Agree will all that has been said, another negative for the single core is that it usually has just one sheathing but with twin and 3 core you get the extra protection of the outer sheathing.
David MH

 

[gus]

If you have your mast off, make up pipe insulation sleeve to run all your cables in. That way they won't slap about inside the mast.

 

[zoidberg]

That all sounds good.
I have my answer.... thanks.

 

[Hallberg-Rassy]

If you have your mast off, make up pipe insulation sleeve to run all your cables in. That way they won't slap about inside the mast.

I was thinking similar, like pulling some used 6 pack, plastic rings up there to hold them in place.

 

[zoidberg]

......That way they won't slap about inside the mast.

I'm also looking to use 1/4" plastic cable ties, paired, where the protruding long ends will help prevent 'slap'.

 

[rogerthebodger]

When I rewired my 15 meter aluminium mast I made up brackets to hold (pop riveted from the outside) plastic trunking up the inside of the mast extrusion at the front and back of the mast. The fromt was used for the steaming , deck and spreader lights and the aft was to all the fittings at the top of the mast. tri colour, anchor, wind sensor and coax cable

 

[garvellachs]

Changing to LEDs means the cables can be thinner.

 

[William_H]

While you have the mast on trestles, Zoidberg, what about running a thick copper welding cable down from the top, and rigging up a lightning conductor and dispersion system exiting from the base of the mast ?

Assuming you are serious.... An ali mast will have much lower resistance than a welding cable so no point in fitting the cable in the mast. From the base of the mast to water yes but not in the mast. ol'will

 

[Jokani]

When I rewired my 15 meter aluminium mast I made up brackets to hold (pop riveted from the outside) plastic trunking up the inside of the mast extrusion at the front and back of the mast. The front was used for the steaming , deck and spreader lights and the aft was to all the fittings at the top of the mast. tri colour, anchor, wind sensor and coax cable

Hi Roger, sorry to drag this post 2020 post back up, can you give a little more detail on the type of trunking, the brackets, and how you managed to rivet all the way along the mast?

 

[pandos]

Already said elsewhere