Negative grounding my tower - bad mojo or?

So I am building a custom light bar for my tower because I can't find one that has everything I want the way I want it. I am thinking about running a ground wire to the mounting bolts of the tower within the hull so the whole tower will have a negative ground. Then rather than running an additional wire down the tube and into the cabin I can just ground the lights directly to the tower itself up above, maybe within the mounting bolts or brackets or at least close by.

However I'm no electrician or expert so I'm wondering if that can cause any problems... Such as buzzing in my tower speakers, generating excessive heat, battery draw, etc. Right now the only wiring running through my tower is double shielded stereo speaker wires to the cans above.

And yes, I tend to come up with these brilliant ideas that don't always turn out that way in the end... Hence the post here.

Thanks.

Ground everything at the battery. Stereo, other mods are best grounded at a common point and the ground block under the dash is not always the best place. Grounding a tower IMO at the mounting bolts isn't going to do anything because the tower isn't grounded to anything eighter.

Im no electrician eighter but if the tower was a good ground then the Nav light on the tower would be grounded there also.

Right - everything is grounded at the batteries. However I'd run a dedicated line from the negative on the battery to the mounting bolts on the tower. Then the whole tower would be grounded negative and I'd just tie directly into it for the negative on the lights. I've avoided adding anything else to my negative block under the dash besides a single line for LEDs - don't want to overload it.

I have no lights on my tower at the moment. I'll be running 2 forward spotlights, 2 rear spot lights, my anchor light and a downfiring LED bar. The spotlights will probably not get a heck of a lot of use but the LED bar and anchor light (most likely LED) will, hopefully anyway!

Part of my reasoning for this is to get away with a simple 4-wire loom going through the tube to the light bar: 1- fwd spots, 1- rear spots, 1- anchor light, 1- leds. If they are all grounded to the tower itself up high then I can avoid needing a 5th grounding wire.

I am running massive 0/1 wire both +/- for my amps to Kicker distribution blocks - not going to mess with that. This would be independent of everything else.

Best i can tell ya on this is try it out before fishing all those wires threw and see what happens. Make sure you hook up your fake a lake and run the engine to see what happens that way you can check for noise.

I would say you can use the tower as the ground baring any ground loops that would affect the stereo. The resistivity isn't that much different for aluminum versus a copper wire.

http://hypertextbook.com/facts/2004/ValPolyakov.shtml

one reason a commin ground point is nice is for diagnosis, if you get a weird light problem, or corrosion, tracing wires and connections down can be fun. a common ground in any system is a good thing, usually if there is a bad ground everything on that ground is acting weird not just one piece. I understand wanting to make the tower a negative ground, i would at least ground all of the lights at one point on the tower.

Let's say your use the tower for ground provided you verify its high conductivity. Okay, so lets say a speaker wire or connection inside the tower gets a little chafed and exposed. That amplifier channel is possibly lost now. Otherwise its a forgiving situation. I'd consider this a bad practice.

David
Earmark Marine