Running NAC A5 under the house

I used to work for a large Buildeers Merchant and we sold cable ducting of various diameters with different bends fitting etc.

This was for external or underground usage so is very durable might be worth a look.

Agree cable ducting or trunking.    I would caution against using round section conduit tubing,  NACA5 is very stiff - & although not impossible - its very difficult to get around bends.  PVC trunking with clip on top sections is ideal;  but thinking bends,  be sure the duct size can take the NACA5 in both H & W as the NACA5 will need to be turned "on end" to go round a bend.

Look up Polypipe cable ducting on the internet that will give you an idea of what is avalible.

I find plastic plumbing pipe to be good for cable ducting. You can bend it into position and fix it with pipe clips if required. Much easier than trying to force NACA5 round a sharp 90 degree bend. The smooth internal surface makes feeding cables very easy. 

I'd try MDPE water pipe as they go up to 60mm diameter and are indestructible. I often use this as added protection to runs of underground amourcoure cabling. You can't have any right angle bends though, which you probably don't want as NAC5 would never go round them anyway.

Look up Polypipe cable ducting on the internet that will give you an idea of what is avalible.

If you look they have bends that allow cable to be drawn through using a simple draw cord to pll cables through this is the same as the cable companies use.

The OP is from New Zealand,  no Polypipe,   he needs to take a trip to the local Bunnings Warehouse

I just ran my 8m pair loose under the floor.   It is not like we have any traffic under there, and the cables don't see much current.  I don't know how it affects the sound and I don't want to know.   Net of any detriments, it sounds great at my house.

No reason to assume pipe/conduit is by any means required.

I have 8.5-m lengths of NACA5 that run naked through my crawl space. Been there for over four years with no issues. I made certain my crawl space was absolutely rodent proof before installing the NACA5. The only interlopers I find in are spiders and they've been no detriment. Why make things more difficult or expensive than necessary?

Just in case I will use a pipe. Perhaps a PVC pipe simmilar to those used for water drain will be perfect. No moisture and no external effects. They are also a wide rande of diameters.

Just in case of what?

Joerand,

You are going to run the cable outside. I think that you must think in a permanent installation. Can years of exposing to external moisture affects the copper in the cable? Can any animal reach the cable? What about rain effect during years? Can wide changes in temperature affects cable insulation?... I have no answer to any of these questions... so just in case.

...Javi

Javi,

Aha. Your OP stated you'd be running the cable "under the house", so I understood that to mean crawlspace. As you're actually running it next to the house and outside the foundation, then yes, by all means a conduit seems in order.

Ducting under the floor could be an idea if you ever think of ungrading the speaker cable - could make the swap a little easier....

Mice would be my main concern. Thread the naca5 into blue water pipe (very easy) and seal up at the ends. A rat would get through it, but you'd be unlucky. 

Are we burying the cable or just running it under the floorboards? I can't see the need for piping for the latter.

If the floors are to be carpeted then you can just carve out a NACA5 sized canal in the underlay and won't need to go under the boards. 

Thor uses Mjolnir to chase a trench in the palace HiFi room.

Hi Ade

I simply used hanging loops from my floor joists as I was uncertain of the effect of cable-duct contact. I'd previously used floor lifters to noticeable benefit. I wanted to avoid any microphony effects.

I'd caution running two cables close together in a common duct.  With 52/135s increasing the distance between NACA5 runs to > 8 cm was more musical and transparent.  Naim have gone to a lot of trouble to reduce noise floor and any degree of cross coupling will have an impact.

Aeroflex is superb for protecting cable and isolating it from vibration. I even use Aeroflex lagging on speaker cables in the lounge because of the dampening effect and it also provides excellent separation from other parallel running cables. Most pipe lagging is not really very good for putting cables in because it actually offers almost no microphonic isolation. Aeroflex is low cost. I can't recommend it enough.