Cheap outdoor speaker cable

[Mark M]

I have some cheap rock speakers to put into my garden that run off an old hifi amp I had spare and need to run about 50m's of cable in total for the 4 of them.

I'm going to run it underground to the fence and them along the underneath of the fence supports. I previously used some cat5 that I had lying around but I dont have enough left so will need to buy something. I wasnt sure if I could used some cheap eletrical cable perhaps to keep the cost down? Its only for background music at parties etc. Thanks

 

[lucid]

Watch out for rodents eating through speaker wire / electrical cables / Cat cable. Don't ask me why they do it; they just do.

If you live somewhere where rabbits, moles etc make an appearance then make sure whatever you buy is laid in to conduit before burying it, otherwise you'll be digging it back up again in 18 months time.

Yes, you can use electrical cable. It's pure copper through and through rather than copper coated -aluminium (CCA) or -steel (CCS) which is what you'll find with cheap cables from wholesalers/online/Ebay.

The thicker the cable then the smaller the power loss over distance. 0.75mm twin electrical flex will lose roughly 20% of your amp power over 20m. The losses through 1.5mm twin flex will be less than 10% for the same distance. These are all 100% copper, as per electrical regs. 2.5mm pure copper is only a couple of percent better at 20m. The smaller loss isn't worth the extra cost for short distances. Stick with 1.5mm cross sectional area.

CCA cable is roughly 60% as conductive as pure copper. Aluminium is a poor conductor compared to copper at the sort of low voltages used for audio. So for every 100Watts through copper a CCA cable of the same thickness will give you just 60W. You lose 40% of the power with the cheap cable. That's big losses for the small amount you save. Cheap (crappy) cable is a false economy.

The other thing with aluminium is that it is brittle. I went to commission a data network in a house that a Spark had prewired. He'd used CCA Cat cable not realising the issues. There were broken tails and lines down all over. He had to pull it all out and install the pure copper stuff which is what was on the original quote. That's an expensive mistake.