Rewire question - Fuel Ground

[Reel Hattitude]

I seen many discussions on this but not directly to my questions. Gas tank was replaced recently so I wanted to confirm proper configuration. I have a green ground running duel connected (two wires split) to tank ground bar and fuel sender running to negative bus in console. Likewise have green ground running from fuel fill to same negative bus. Is this correct or 1. Does it need to connect directly to battery for some reason 2. Do both runs need to be connected in-line (same bus terminal) 3. Perhaps silly but does this wire need to have a fuse? Thanks.

 

[seasick]

It's fine and appropriate since the negative bus at the fuse panel is directly connected to the battery ground. When it comes to grounds, you really don't want multiple grounds paths for the same ground point. Multiple paths create what are called ground loops and those can cause currents to flow in conductors and create small voltage differences where you don't want them.
Note that the grounds you mentioned deal with two different electrical needs: One is a DC return path for signals like the fuel sender and everything else that runs on battery. The the second purpose is to help eliminate the buildup of static electricity. When equipped with shore power, things get more complicated but the theories are the same.

 

[DennisG01]

And... no, you don't need a fuse on a ground/negative wire.

 

[SkunkBoat]

And... no, you don't need a fuse on a ground/negative wire.

and should not put one there....

 

[seasick]

Wow, I missed that question!
Agreed, never fuse a ground run (or a neutral for that matter).

 

[Fishtales]

Agree with all for a marine application.
The only condition where fusing both phase and neutral conductors yields non-redundant protection against both faults is where polarity reversal is possible. That is, where the phase and neutral conductors could be interchanged on the supply side of the fuse. If polarity reversal is possible, then double-fusing guarantees that the phase conductor will always be provided with a fuse.

 

[seasick]

That's interesting but I am not what exactly it means to say "where polarity reversal is possible" Is the possibility due to wiring errors or something else?
It's been a while since I 'studied' the electric code but I do know that if a neutral is fused and blows, it is possible and likely that devices will have line voltage but you don't know that since there will not be any current draw. In other words, nothing lights up so he power must be off
Are there applications where polarity reversal is unavoidable ( and not due to ignorance)?.

 

[DennisG01]

Are there applications where polarity reversal is unavoidable ( and not due to ignorance)?.

Ignorance, for sure. Not sure about other reasons. But coming from a bunch of expereince with cruisers - or any boat with shore power for that matter - the main electrical board on the boat will often have a "reversed polarity" light. So if you hook up to dock power and you see that red light lit up, you know to unhook. In all the docks I've been to, I've never personally see it light up - but I have read about others where it has. Must happen enough to warrant the boat manufacturers installing the reversed polarity light.

 

[Reel Hattitude]

It's fine and appropriate since the negative bus at the fuse panel is directly connected to the battery ground. When it comes to grounds, you really don't want multiple grounds paths for the same ground point. Multiple paths create what are called ground loops and those can cause currents to flow in conductors and create small voltage differences where you don't want them.
Note that the grounds you mentioned deal with two different electrical needs: One is a DC return path for signals like the fuel sender and everything else that runs on battery. The the second purpose is to help eliminate the buildup of static electricity. When equipped with shore power, things get more complicated but the theories are the same.

Thank you