Is it ok to earth onto bolts onto ali panels rivitted to the chassis, ie does ali provide as good an earth as the steel chassis?

This is what we have done with our fuel pump and continuity seems to be fine. Fuel pump bolted to ali mount, earthed to same mount via a rivet. Ali mount then riveted to chassis. Checked continuity to one of the wheel rims and seemed to be a good circuit. Not sure on the relative conductivity of ali versus steel, but I'm pretty sure that all metal conducts so would have thought it would be fine.

Of course I might be talking out of my ear, in which case someone correct me and we will have to redo our fuel pump!

Ali is a far better conductor than steel, not quite as good as copper.

Earth returns through the ali will be fine, with one reservation: aluminium oxide is an excellent insulator, so keeping a good connection may be a problem. However, it's not a major issue - just take care to keep water out of the joint.

David

Cheers chaps

I guess a blob of silicon sealant over the top of the rivet might be in order then

i,d put an earth lead on just in case

just cos something is in vague contact - ie a rivet against an alu sheet - does not mena its a good consistent long term earth.

If its drawing several amps, or important, I would earth bong the panel by more positive means.

atb

steve

It is true that alloy will provide a suitable earth path, however it is also a fact that dissimilar metals in contact and in the presence of an electrolyte, (water) will set up galvanic action, (they act like a battery). This induces corrosion, the products of which will not conduct. Wherever possible alloy should be insulated from steel using sealant. IMHO the best method would be to bond the components electrically to a steel chassis member.

Mick

a good fix might be to scuff arounf the rivet and put a spot of solder on it. also anywhere you have a screw for a ground make sure to put on silicon dielectric grease on it. (good old petroleum jelly works too)

nick