Earth Cables Issues Fiat/Peugeot Vehicles

Look for Earth cable issues if you have a varying engine Idle speed or reduced habitation battery voltage.

In the photo below while the cable looks ok, corrosion usually takes place between the Copper Braid and where the Steel eyelet connector crimps onto the Copper. 

Over time Water gets into the joint, leading to electrolytic action, and the Copper/Crimp connection breaks down.



Any cable that is made up of Copper with Steel clamped on/Crimp connectors will have the same issues over time. 

If Road Salt water can get between the copper and the crimp connector there will be corrosion inside the connection where it is not visible. It won't be a question of 'if' it breaks down, but when.

Typically these Earth Straps have a 3 - 5 year life.


We suggest the solution is a braided cable that does not have Steel Crimp connectors, just holes where a washer and bolt clamp it to the body/Gearbox point. Something like : 

A good size is about 25mm wide and 4mm thick (continuous 205amp rating). The length will depend on where you plan on fitting it. 

To replace a Fiat X250 standard lead you will need a length about 150mm long. Probably about 700mm for a secondary earth strap?

This company sell Tinned Copper Braid in 1,000mm lengths at about £13,  www.copperbraid.co.uk

see : https://www.copperbraid.co.uk/product/copper-braids/?Type=CopperFlatTinned&CS=35

They also sell made to measure lengths.


If the braiding has no pre-manufactured holes, they can usually be parted easily enough with a screw driver to create a hole big enough to accept a 10mm bolt and washer. Try not to Drill/Cut it, but part the braids if you can as that will be stronger.

If you fold over the Braid ends to give about a 30mm double layer and put the bolt/washer through both layers it should be quite secure and resistant to fraying. Obviously soldering the end will be better still.

Suggest any hole is at least 15mm from the end of the Braid. 

Even better, double layer the whole cable, say 20mm x 3mm doubled, so you have twice the current rating and even stronger connection points. Allow plenty of play for engine movement which can be significant as the vehicle ages/higher mileages. 


Below is a cable made up in advance ready to fit. It is easier to build/assemble it off the vehicle. 




Bend over the end for strength and then push through the Chassis/Gearbox bolt with the washers either side and a 'dummy' nut to clamp/compress it all together. Preassemble it, like in the above photo, before fitting it to the vehicle.

Once preassembled remove the nut and it's washer and fit onto the vehicle. The Braid holds the Bolt tight in place so it is actually less fiddly to fit than the standard cable.

Don't overtighten the Bolts into the gearbox, 10mm bolts in Soft Aluminium will only need a few lbs of Torque.


Obviously important that the Braided cable is clamped with a washer (about 25mm across?)  to spread the mechanical and electrical load. 

There may still be corrosion at the contact points where the bolts go through because the cable sits where it catches all the road spray. However removing the bolts every few years and cleaning them should keep the current flowing. At least any corrosion will be visible and easily cleaned off. 

Most likely only the clamping Washers will be affected by corrosion, the Braided cable should last indefinitely. 


Better still, especially if you want a Garage to fit one, is to fit a completely new cable at the top of the engine out of the road spray. 

If the cable has corroded, then it's possible the fastenings have corroded as well. If you ask a Garage to replace an Earth strap and bolts/nuts become sheered or threads stripped, then a 5 minute job could turn into an expensive one. 

If the Garage leaves the original Earth Strap undisturbed and just fits a new strap on the top of the engine there shouldn't be any surprises on the bill. It is only a 10 minute job, literally.  



We replaced an Earth strap between Gearbox and Chassis in December 2015 and it took 10 minutes. With the 'joints' now being more open it should dry out more readily and the Tinned coating should also extend it's useful life. We would guess at least 8 year useful life. When the cable does begin to suffer, it all comes apart very easily for inspection, cleaning, refitting and another 8 years life.



Fiat X250 supplementry Earth Strap.

For an example of a secondary top engine bay Earth Strap, this is a suggested DIY approach that we helped the owner do as an example in February 2015 on a Fiat X250 Auto :


You will note that Earth point on top of the engine is to a Water tube mount with a pre-drilled hole that is usually free. This Water tube mounts to the engine at over four separate points so there should always be good contact. The other end is wired to the front crossmember, see it over on the right hand side of the photo.

While we do not suggest this is how a Garage should fit one of these upper earth straps, this is a suggested approach for easy DIY. It might not be the prettiest but is functional, quick and easy for someone with minimum skills. It is at the top of the engine so not only easy to work on, but out of the majority of the Salt Spray.

A second Strap from the new one to the battery Negative would also be a good idea, but it's not a short or easy cable run. 

Suggest it might be a idea to use grease on the bolt threads.



This company below sell a £7 ready made Tinned Copper Braid in varying lengths with M10 holes each end of the Tinned Braid to replace an X250 original lead. You may need washers under the Bolt head.

https://www.ebay.co.uk/itm/250mm-x-25mm-BRAIDED-EARTH-STRAP-LEAD-ALT-EC25-250/381677889589?hash=item58ddc66835:m:mJoNAQDi5WRTAWVUOUPNOeQ


You will note there are no 'Crimped' connectors to corrode. They also sell the same in "150mm (r), 250mm, 300mm (r), 375mm (r) & 500mm (f) lengths"..