Does the + and - connection wires have to stay the same length?

[GimmyTree]

If I put fuses complete with fuse holders on the positive connection wires, that will make the positive wires 20cm longer (with the fuses attached) than the negative wires. 

Will this make much of a difference for anything?, or should I shorten the positive wires to compensate for the 20cm fuses?

[B and C]

They do not need to be the same length.

[GotSmart]

Close enough. 

[GimmyTree]

Alright, thanks guys.

[rvpopeye]

Only if it makes it look pretty(er) !

[Roadtripp]

My 2cents worth is the DC power wires do not “have” to be the same length but I make them the same length as a general good practice.  I sometimes shorten the wires that come with inline fuse holders so it’s almost the same length as the negative wire. Or leave the fuse wire long and use the extra length to secure the wire to something. So “relative placement” is a factor also in wiring.

[rvpopeye]

I used to work with a master on a lot of gigs for a couple of years and he used to ride me about how particular I was about wiring layouts...... It's really not just about making it pretty , but it does help in other ways.

[B and C]

Troubleshooting being the biggest.

[Ticklebelly]

Standard work practice in a Telecommunications company I worked for at one time, was to have flying leads at unequal lengths. Minimises the chance of the ends shorting to each other while connecting or disconnecting leads.

[Matlock]

Course those folks using the vehicle frame for the neutral may have some serious calculations I'd guess. And does girth play a factor in them numbers too?