Wiring diameter

[obmij]

I'm starting a rewire and am commencing with the engine. The existing wiring is of different sizes and the wiring diagram in the workshop manual specifies those sizes.

Do I need to stick to this or can I overspec? Would there be any disadvantage in using 6mm2 insted of 1.5mm2 for example.

Any recommendations for suppliers of tinned wire would also be appreciated as well as any general hints.

Cheers

 

[pvb]

Why might you want to use wire 4 times heavier than the manufacturer specifies?

 

[maby]

Electrically, there's no particular downside to using heavier wire - mechanically might be a different thing...

 

[Vara]

Why might you want to use wire 4 times heavier than the manufacturer specifies?

Because it's cheaper to buy cable in large rolls than it is to buy lots of smaller lengths, I have the same query. Thinking that if correctly fused it shouldn't be a problem, but prepared to be put right.

 

[David2452]

Seems a bit pointless, unless you already have the cable and don't want to buy any more. Fuses need to be correct obviously.

 

[obmij]

Yes it's cost and convenience. There are 7 different wire sizes specified for the engine alone. That's before I start faffing around with the rest of the instruments / lights etc.

If I could get that down to 2 or 3 then great.

If not I'll replace like for like. This will probably mean several online orders as I can't find a local supplier of tinned copper wire.

 

[nigelmercier]

I would be happy to double the size of an existing wire, but not much more. Stick with the original fuses.
If it were me I'd buy the right cables and sell the remainder on eBay, or here. Note also that some wires really don't need to be tinned.

 

[maby]

Yes it's cost and convenience. There are 7 different wire sizes specified for the engine alone. That's before I start faffing around with the rest of the instruments / lights etc.

If I could get that down to 2 or 3 then great.

If not I'll replace like for like. This will probably mean several online orders as I can't find a local supplier of tinned copper wire.

Provided the thicker stuff will fit through conduits/wiring harnesses/holes in bulkheads and will fit into the required screw terminals etc. then there is no reason why you should not use it.

 

[savageseadog]

Wiring with larger size can be a sound idea as long as the wire fits the connectors and spaces it needs to go through.
Larger wiring will be better protected given the same fuse size, it will survive a short circuit better for a given fuse size.

 

[jac]

The other positive is minimising resistance and voltage drop. The downside (assuming it fits) is weight and cost.

One factor though is that if the existing set up has different sized wires it makes tracing them easier than if every single wire is physically identical.

 

[prv]

The other positive is minimising resistance and voltage drop.

Plus physical robustness, where the original wiring was really small.

For what it's worth, during my last rewire and in preparation for another this winter, I keep a large reel of 1.5mm^2 on hand plus a smaller reel of 2.5mm^2. Larger sizes for fridge compressor, battery to panel, etc and actual battery wiring, I order specifically by the metre (but generously oversized so there's usually a bit of surplus lying about as well).

Pete

 

[nigelmercier]

^ I had a clear-out last month, threw away any bits of red or black wire less than 2m, except those > 16mm²

Two days later I needed a few short lengths of wire ...