I have attic storage, how does that affect solar?

All wiring has to be supported and protected.

A lot of your normal AC wiring is just thrown into the low parts of you roof space because anything under 600mm high is deemed inaccessible. It's quick and easy because otherwise you have to secure it out of harms way with a clip every 300mm.

However Solar DC wiring has special requirements, namely it must be in heavy duty conduit and labeled regularly for it's entire length and can't be run across the top of the ceiling. (unless it's within the 600mm inaccessible zone) It must otherwise be fixed up, away from foot traffic and out of access paths. 

I'd like to say the DC wiring in this roof space is exceptional but this is often how it ends up, the quickest and most efficient way from point A to point B is a straight line so this homeowner has to duck and weave through the white conduits you can see strung across the space.

I have myself found it challenging to put conduits really neatly into a roof space. Corrugated conduit is floppy and more difficult to thread cables through, rigid conduit is self supporting but hard to restrain if you're forcing it into a corner. Adding elbows and fittings is a complete waste of time and resources, plus it can be a challenge to reach the full height of the roof space with your screw gun.

There are exceptions to the rule of course, this customer was very technical and insisted neatness came before anything else. No joiners or flex, this is conduit hand formed with a heat gun and bending spring.

What I'm trying to say is that complex "neat" routing of the DC wiring in the roof is particularly time consuming. Most people simply aren't willing to pay for it and in the bulk of cases it's out of sight and simply doesn't matter, but that does of course open up the possibility of poor quality work so be aware and set expectations beforehand if you need to.

Things to bear in mind are :

• If your roof is already full of stuff, an electrician may need to climb over it

• If you're planning a storage space, especially if it's going to be lined, then please make sure to inform your electrician.

• Coming back to change DC wiring can be just as time consuming as the original install.