Coax cable for DC power - Page 1
Forum section: electronics / beginners

author: Strand17
author_rank: Contributor
timestamp: March 31, 2021, 08:15:31 pm
content: Hello,I need help identifying a type of cable.Some laptop power supplies use a coax cable with large conductor cross-section on the DC side. What is the proper designation for this kind of cable? I have tried searching at both Mouser and DigiKey, but without luck. I must be missing the right search terms...Are there triaxial cables of this kind available too?Any help would be very appreciated!Jonas

author: mvs
author_rank: Frequent Contributor
timestamp: March 31, 2021, 09:11:30 pm
content: UL style 10846 cables are used in laptop power supplieshttps://www.digikey.com/products/en/cables-wires/single-conductor-cables-hook-up-wire/474?k=UL+10846

author: bob91343
author_rank: Super Contributor
timestamp: March 31, 2021, 10:51:32 pm
content: Confusion reigns. First, power supplies seldom use coaxial cable. They might use shielded cable for rejection of radiated interference. Second, the link above goes to hookup wire, not coaxial or shielded.The only concerns are that the wire is of sufficent gauge to carry the current, and sufficient insulation to stand off the voltage. Plus, environment is important as well.

author: mvs
author_rank: Frequent Contributor
timestamp: April 01, 2021, 12:39:13 pm
content: Quote from: bob91343 on March 31, 2021, 10:51:32 pmLink is correct, UL 10846 is shielded hookup wire.Quote from: bob91343 on March 31, 2021, 10:51:32 pmNo, it is not the main reason. This coaxial construction allows to build compact cable with good flexibility in any direction.

author: fordem
author_rank: Regular Contributor
timestamp: April 01, 2021, 01:28:43 pm
content: Quote from: bob91343 on March 31, 2021, 10:51:32 pmQuote from: WikipediaCoaxial or co-axial is simply a description of the cable construction, and most laptop power adapters do in fact use a co-axial cable, which may not be the same as a shielded cable, that might be dependent on the nature of the shielding conductor, as with a laptop power adapter, the "shield" is required to handle the current drawn by the laptop, which can range from 2~3 amps to as much as 12~15 amps.Cables with a third conductor do exist, Dell AC adapters in particular have a "data circuit" in addition to the two power carrying conductors - the laptops can determine the "wattage" of the adapter and will disable the battery charger if the AC adapter is a lower than required wattage, or it cannot identify the adapter.Also - possibly worth a mention - all new residential AC utility power installations where I live are being run over co-axial cableby the utility company. Older installations are being retrofitted with the same co-axial drops.

author: bob91343
author_rank: Super Contributor
timestamp: April 01, 2021, 06:39:27 pm
content: To be precise, coaxial means sharing the same axis. In other words, some effort is made to make the center conductor actually in the center. Otherwise its high frequency integrity is compromised and it's just shielded cable.It's a bit more expensive than hookup wire and so only gets used when necessary for noise rejection or compactness of cable.

author: Terry Bites
author_rank: Super Contributor
timestamp: April 02, 2021, 03:42:25 pm
content: I think you mean a shielded cable rather than COAX. Coaxial cables are for RF not power. The shield is to keep the PSU noise from leaking out. Poorly in most cases! You can buy triax but you'd be wasting your hard-earned cash. It's a very esoteric cable used in studio digital video and nano volt measurements.There are a plethora of shielded multicore multi pair cables you can buy.https://www.google.co.uk/search?q=shielded+multicore&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiCqImV8d_vAhXa8LsIHT1fDzEQ_AUoAnoECAEQBA&biw=1825&bih=1010

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 02, 2021, 04:15:18 pm
content: Quote from: Terry Bites on April 02, 2021, 03:42:25 pm

author: TimNJ
author_rank: Super Contributor
timestamp: April 02, 2021, 08:08:08 pm
content: UL1185? If you have the cable in question, did you check the text on the cable to see if there was some UL style number?More of a spiral wrap than coaxial. I think the main point of this style of cable is to maximize conductor cross section for a given outer diameter. The spiral-wrap may also have some EMI advantage compared to parallel pair.

author: Terry Bites
author_rank: Super Contributor
timestamp: April 03, 2021, 01:44:37 pm
content: You are ripple on my rail son.