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Earth
rdodger - 7/12/12 at 08:03 PM

Earths?

I am about to start stripping out the unnecessary parts of my donor MX5 loom and route it around my chassis.

There are lots of different earth points for lights etc all over the loom. Do I try and keep them all or reduce/group them to a couple of points?

Cheers?

r1_pete - 7/12/12 at 08:11 PM

Keep the ones for which you are using the component, don't group them, remember they handle the same current as the positive side of the load.

rdodger - 7/12/12 at 08:16 PM

Ah yes, good point!

Would it be good practice to use a steel rivnut in the chassis and bolt them to that?

steve m - 7/12/12 at 08:17 PM

I learnt from having a lotus elan (fiberglass body) that having every single item individualy earthed was the way to go

it is wastfull, of connectors, and wire, but seemed to of worked ok on my 7

Steve

designer - 7/12/12 at 08:35 PM

You can more than a single earth to the same point, the rules are:

- Never connect more than 4
- Always use the same size earth wire as the component feed

snowy2 - 7/12/12 at 09:24 PM

I wouldn't worry about how many earths you put on one connectorbut then i would never advise you to reuse a donors wiring loom. make your own it will work better.

Jimfin - 7/12/12 at 11:09 PM

These seem to work well - essentially a spade connector which you can position conveniently for a couple of earth points adjacent to the components as you need. (assuming the link works!)

5 x Pop rivet earth terminals cars vans Land Rovers

designer - 8/12/12 at 10:12 AM

NEVER more than four earth connections.

Rivet a couple of these, forming a square, to frame at convenient places:


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RichardK - 8/12/12 at 11:47 AM

I welded m6 bolts by the hex head to the chassis at various points, each corner and a couple in other areas so then you can put eyelets on wires and a nuts a tighten them down. This was to service each light cluster really.

Cheers

Rich

[Edited on 8/12/12 by RichardK]

RichardK - 8/12/12 at 11:50 AM

quote:
Originally posted by designer
NEVER more than four earth connections.


Why is that,on these cars that are hardly pulling any current? Probably me but I don't understand the logic behind that.

Cheers

Rich

[Edited on 8/12/12 by RichardK]

coyoteboy - 8/12/12 at 04:43 PM

quote:

NEVER more than four earth connections.


Where do you get that from? There's absolutely no logical reasoning behind that. There's a damn good reason to ground points to certain points together, and to keep others away from each other, but numerically limiting it is a farce.

snowy2 - 9/12/12 at 09:03 AM

I really do not see why a limit of 4 connections should be necessary there is no sound electrical reason for it. But several why it should not be the case (fault finding for one) bear in mind that the chassis is one large conductor in this earth circuit and the electricity dont care where it goes and most certainly not if it has to share an earth point. Scania (Saab) and VW use earth spade terminals that are circular in design and have 8 spade terminals on them, these often have multiple earth wires into each spade connection so literally dozens of wires all earth through one self tapper.

big_wasa - 9/12/12 at 11:28 AM

I wouldn't use rivets or rivnuts for earths. They can work loose and play up.

The Black Flash - 17/12/12 at 01:53 PM

quote:
Originally posted by RichardK
I welded m6 bolts by the hex head to the chassis at various points, each corner and a couple in other areas so then you can put eyelets on wires and a nuts a tighten them down. This was to service each light cluster really.

Cheers

Rich

[Edited on 8/12/12 by RichardK]


This is the best way I think. I did the opposite and welded threaded bosses on, but a bolt would have been simpler. Nice to avoid bare holes in the chassis if you can.