'Bundling' of 12V cables

[zoidberg]

I have a qwessie on the effects of 'bundling' groups of 6 x 12V 21Amp wiring within spiralwrap. I don't expect any one wire, each ~1metre long, to carry >15amps ( bilge pump ) and asked the cablewrap makers' tech support. They pointed to 'BS 7671 (18th Edition) wiring regulations. For detailed calculations refer to Appendix 4, which provides tables for cable grouping.'

Can anyone here give more helpful guidance?

 

[PaulRainbow]

Spiral wrap is horrible, nasty looking crap. Either cable tie every 150mm-200mm and secure with cable tie saddles or put it in some trunking.

 

[wonkywinch]

Better still, learn to lace, it's ropework only smaller

Cable Lacing | Lacing Cord | RS

 

[oilybilge]

Better still, learn to lace, it's ropework only smaller

Cable Lacing | Lacing Cord | RS

I just googled this and ended up at r/cableporn

I'll be in my bunk

 

[PaulRainbow]

Better still, learn to lace, it's ropework only smaller

Cable Lacing | Lacing Cord | RS

As long as you'll never need to add or remove a wire

 

[The Q]

Better still, learn to lace, it's ropework only smaller

Cable Lacing | Lacing Cord | RS

I did.. 50 years ago being taught by Derek Shaw, the workshop practices instructor at RAF Locking.

However the question posed is not about how to bundle cables. But about the effects of cable heating when tieing bundles together. Like you should always unwind an extension cable before applying power, you should be cautious bundling power cables together to prevent melt down.

Sadly as I'm busy packing and this is a coffee break, I don't have time to do the required sums..

 

[Boater Sam]

18th edition does not relate to 12v.
Heating is not a problem providing the volt drop calculation for the current in each cable has been correct.

 

[PCUK]

Split conduit. All sizes available. Easy to use and looks professional.

 

[jamie N]

I like spiral wrap as it prevents chafe, and is great on a 'new' system, but as a cable bundling thing for an engineer to have to work on, @PaulRainbow is absolutely right.

 

[Chiara’s slave]

Correctly sized and fused, bundle all you want. The size might be different when you bundle, be aware. The size for open air cables is smaller than those that are confined.

 

[PaulRainbow]

I have a qwessie on the effects of 'bundling' groups of 6 x 12V 21Amp wiring within spiralwrap. I don't expect any one wire, each ~1metre long, to carry >15amps ( bilge pump )

All 1m long ? Even the bilge pump ?

Even at 1m long, with 15A loads, 1.5mm cable is too small, should be 2.5mm.