Aluminium fuel tank earth

 Hi everyone ,

im hoping that some of you guys who are way more experienced than myself can clear up a doubt that I am having with my boat? 

In a glass boat - should an aluminium fuel tank be grounded to a negative battery terminal ? 

Not sure if it matters but the fuel tank does have a sender hooked up to digital gauges ?

Thanks in advance 



scano's picture

Posts: 998

Date Joined: 31/05/07

My thoughts would be yes

Mon, 2018-04-16 12:06

 Mainly because how else do you get a completed circuit for the gauge to read correctly? You obviously have the power wire going into the fuel tank sender unit, but you need an earth wire to complete the circuit. 




Posts: 107

Date Joined: 08/05/09

That gauge

Mon, 2018-04-16 12:27

 the gauge is connected via two wires and works spot on - what I am more curious about is whether the tank should be grounded to reduce the risk of ignition ?


ranmar850's picture

Posts: 1774

Date Joined: 12/08/12

tanks can be grounded

Mon, 2018-04-16 14:15

 The wire will go to the filler neck to reduce the risk of static spark, or am i wrong? I have to investigate this myself, the new boat has a sender unit installed, but no gauge fitted, probably won't bother.

squidvicious1's picture

Posts: 573

Date Joined: 22/07/10

 I’ve got a fibreglass boat

Mon, 2018-04-16 16:28

 I’ve got a fibreglass boat with a metal tank and only have the 2 wires coming out of the floor going to the gauge.

just dhu it's picture

Posts: 1058

Date Joined: 14/05/09

No earth

Tue, 2018-04-17 06:38

 the boat is glass and no potential between tank and glass body , as ramnar said the only earth would be for static prevent but in most cases now they use anti static plastic as the filler and tank are only connected via a rubber hose,  the sender unit is a resistor and only requires two wires , where as your gauge will have the positive and negative connected , ie the sender acts like a switch in the circuit



ranmar850's picture

Posts: 1774

Date Joined: 12/08/12

That would probably explain

Tue, 2018-04-17 07:54

 The black and white wires protrudng from the wiring harness down the back; power connections to sender? I may fit a gauge, as a backup and crosscheck to the electronic monitoring. I still have a TINY bit of room on the dash.

just dhu it's picture

Posts: 1058

Date Joined: 14/05/09


Tue, 2018-04-17 17:41

 Depending on your motor choice. Most motor gauges now have the dual level indicator as one of their views that you can scroll through so seperate fuel gauge won't be required

Stevo81's picture

Posts: 1009

Date Joined: 16/04/12

Once networked, your Axiom

Tue, 2018-04-17 18:59

Once networked, your Axiom will be able to show you fuel remaining in Litres. Tell it your tank size and when you have filled it and it will calculate back from the engines ECU fuel burn. Mine is near on perfect. 


                                   ••••••••  Electrical Contractor NOR  ••••••••

Posts: 107

Date Joined: 08/05/09

Thanks everyone

Wed, 2018-04-18 08:52

 thanks for your input guys !