Mast wiring

[packman]

I'm getting ready to wire my new mast and wondering if I can use the mast as a common ground. I'd planned to put in wiring for a masthead tricolor, steaming light, windex light, VHF antenna, and spreader lights. The mast has bars running through to support the spreaders in compression, it also has 4 halyard slots. Gettin' pretty crowded in there. I'd guess that there might be issues with corrosion or a lightning hazard from using the mast as a conductor but I dunno. Is this acceptable practice?

 

[Lee Thompson]

Dont us the mast as a conductor it will cause electrolysis between the aluminum and stainless steel. And on my h27 the mast step is grounded to the lead keel so then you would have trouble thare with the anodes. Lee

 

[Dan Johnson]

Packman...

break down and get yourself two spools of Ancor marine grade wire, one 12 AWG and one 14 AWG, for your project. Each wire run on a boat should be made with Pos and Neg running to and from the same points (panel and item). Due to corrosion and other issues, you can't use metalwork as a ground as you would in a car.

You probably will need 12 AWG wire for the wire run to the spreader lights and 14 AWG may be sufficient for the other low watts/amp draw of the others. Distance and current draw will determine what you should buy.

Whatever's left over from each spool will eventually get used as other projects and improvements are surely on the horizon.

 

[kloudie1]

I have heard of folks saving weight and space by using only one large common ground wire in the mast.. but, as Lee and Dan noted, it is not OK to use the mast itself as a ground.. I know that on my boat, all the mast mounted electrics have individual ground wires, as installed by Hunter originally.

 

[Maine Sail]

In a DC system the negative side carry's current just as the positive side does from the battery and then back to the batt. Simply insert a DC ammeter or DC clamp ammeter in the negative wire and you'll see the current flowing. If you do this the mast becomes energized which can be dangerous. As others have said it will also cause increased corrosion.

The ground system or bonding system is not supposed to be carrying current. A mast, very often a lightning ground, and bonding of seacocks and the ground wires that run to the engine from the ground buss or ground plate should be at earth potential not energized.

All current carrying conductors need to be insulated and should ideally meet UL1426 standards.

 

[packman]

Thanks folks

Thanks for the advice, I was afraid that was the case, nifty solutions rarely are it seems.

 

[kenn]

With planning you can minimize the number of separate wires. I would group your mast fixtures as follows:

(VHF antenna is of course on its own coax)

1-masthead tricolor, windex light
2-steaming light
3-spreader lights

So that's 3 wires, plus a common return. The 3 wires need to be sized for their load, and the common return must be sized for the sum of the 3 load currents.

If you can use LED bulbs or fixtures for any of these, the wire sizes can be reduced, obviously.