Sick of cheap power cords and extension cables for test/power equipment! - Page 1
Forum section: electronics / testgear

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 04:24:43 pm
content: Warning: This is a rant...As I was constructing a new power cord for myAgilent 6675A 120V/18A power supply, I came to the horrid realization that the pre-made cables you can buy on eBay and Amazon are pure crap. I wanted to have a 12/3 portable cord (SJTOOW or STOOW) with a quality NEMA 6-15P or NEMA 6-20P plug on it (e.g., Leviton or Hubbell). I couldn't find anything of the sort, just cheap Chinese made crap with molded on connectors catering to the "buy at the lowest possible price" crowd.Then I started to shop around for 6-15/6-20 extension cords. Once again I ran across the same crap with 14/3 (or 12/3 if you got lucky) crap cables connected to even crappier male/female molded-on connectors. Quality was nowhere to be found, no matter where I looked. Everything was made to the cheapest price point and then sold for ridiculous prices, leading me to the following conclusion:If you want a quality cable with quality connectors, you have no choice but to construct one yourself.Am I crazy in this desire for a quality cable with quality connectors or do others share my opinion?

author: HighVoltage
author_rank: Super Contributor
timestamp: December 18, 2014, 04:35:41 pm
content: Quote from: SharpEars on December 18, 2014, 04:24:43 pmIt is a little better in Germany and most equipment that we buy here, has good quality connectors on both sides and a good quality cable.But from time to time I get a cable that just sucks. Our wall plug here in Germany is much better quality than the US cable connector, so we usually have no problem with that side. But the connector that plugs in to the instruments and the cable itself just suck sometimes.Always test the fitting and internal resistance.

author: mjkuwp
author_rank: Unknown
timestamp: December 18, 2014, 05:05:07 pm
content: Manufacturers are just providing what we (consumers) tend to buy and I'd guess most consumers sort by price.I highly suggest looking at Monoprice.comgranted, the products are not high-end but they are decent quality and you are unlikely to overpay. I buy A/V cables from them and other small gear but I see they also have power cables.I have also connected my own ends onto power cables and for that I go to Menard's or Home Depot

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 05:35:49 pm
content: Quote from: mjkuwp on December 18, 2014, 05:05:07 pmI just checked out Monoprice and they have mostly 16 and 18 AWG with a couple 14 AWG cables. So in other words, exactly the cheap Chinese crap I was ranting about in my original post.Also, I love the disingenuous portrayal of a more conductive better cable by adding more plastic insulation to it thereby increasing its diameter, while still hiding thin copper wires inside.

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2014, 05:40:08 pm
content: Because thinner copper suitable to most applications makes it cheap chinese crap, yes..14AWG is already huge for anything with a C13 on the end.

author: wraper
author_rank: Unknown
timestamp: December 18, 2014, 05:50:38 pm
content: But what do you expect. There is no big reason to use wire thicker than 14 AWG for 15A and 20A current capability of NEMA 6-15P and NEMA 6-20P.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 05:51:14 pm
content: Quote from: Monkeh on December 18, 2014, 05:40:08 pmThat may be true for power cords. But add very long extension cords into the mix. These are very often 16/18 AWG crap also...

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2014, 05:57:06 pm
content: Quote from: SharpEars on December 18, 2014, 05:51:14 pmTheir 100ft extensions are 12AWG. They offer 14AWG and 12AWG for 50ft.Worst case 4% drop for the 100ft, excluding inrush (which I admit is a giant pain with some tools, but that's why we have proper voltages. Large motor loads on 120V are a joke and everyone knows it.).

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 06:04:03 pm
content: Quote from: Monkeh on December 18, 2014, 05:57:06 pmFound that, yep 12 AWG with some seriously crappy connectors...

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2014, 06:05:41 pm
content: Quote from: SharpEars on December 18, 2014, 06:04:03 pmWell they're NEMA, what did you expect?Traditional shots aside, I wouldn't judge them until I got one.

author: SeanB
author_rank: Super Contributor
timestamp: December 18, 2014, 06:14:41 pm
content: It is a pain trying to find a plugtop that will properly fit a 2.5mm cable, most seem to be cut to fit a 1mm cable, and struggle to fit a 1.5mm cable. Luckily I found some used old rubber industrial plugs that still had a cable grip with screws, and these fitted the cable. I do not like having a cord grip holding the inner wires only, though most electricians seem happy with cables that are only fit for cutting into scrap, and the plugs as well are often close to unusable. They are also fond of using lawn mower extension cord and putting a 3 pin earthed socket on the end, but the cord is only a 2 pin one.At least they are better than the builders, who will happily push bare wires into a socket after using a nail to open the shutter, and hold them in with a wet stick jammed into each hole. That is if they do not break the socket and connect to the bare wires direct and leave them dangling, and then use the extension cord with the missing sections of insulation exposing green oxidised copper wire.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 06:16:37 pm
content: Quote from: Monkeh on December 18, 2014, 06:05:41 pmWhat I expect for my minimal value 5-15 terminated crap cable (i.e., extension cord):Plug end:Connector end:In between, decent 12/3 cable, e.g.:What Idon'twant is 16/18 AWG crap with molded connectors in black, orange, yellow, blue or green. Made in China by the hundreds of millions (billions?) for under $1 USD each, then sold on Amazon in 6-10 ft length for $11-$19, I kid you not:

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 06:33:30 pm
content: The SharpEars checklist for "quality power cable."Allof the following must be true for it to be regarded as a good cable:You cut at least one finger trying to strip the jacket off of the cable with a razor blade or a box cutter due to the toughness of the insulation. Bonus points if the cut required stitches and a visit to the ER.Your Irwin VISE-GRIP Self-Adjusting wire stripper can't get the insulation off of even one of the three (12 AWG or larger) wires inside, no matter how many times or at what angles you try. It can't even score the insulation - all it does is stretch it.When you finally resort to using large diagonal cutters to get that darn insulation off of the individual wires, at least one of them loses a copper strand due to you cutting too deep with the cutters into and through its insulation. All is well though, because its just one strand out of the thirty or more in the wire.

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2014, 06:43:08 pm
content: So what you want is expensive rubber cable with expensive connectors which can't be fitted by automated tooling.Yes, you will have to make that yourself.

author: rx8pilot
author_rank: Super Contributor
timestamp: December 18, 2014, 06:46:58 pm
content: For more than 20 years I have been in the entertainment business - mainly specialty camera systems. I have owned sound and lighting trucks and worked in various technical capacities from design, mixing, to "guy who lifts heavy things". In this world 12/3 SO type cable and Hubbell are king of the hill. They are chosen partly becuase they last a very long time in very rough conditions. Also, type SO cable is a requirement in certain locations for safety. That type of cable is designed for brutal duty, mud, foot traffic, etc. I have owned, used, terminated thousands of these things in my early years.I love the 'awesomeness' factor for sure, but could never be convinced that building my bench or any other indoor static setup is worth caring much about. I have been involved in some fixed installations where we used manually terminated SO and SJO types primarily to get exact length cables. Aside from pride and awesomness, do the 6 foot PVC jacketed 16/3 or 14/3 cables cause a real problem? I guess for your 2000+ watt PSU, maybe a 12/3 option is called for, but that is not a normal piece of gear. Crown (the amplifier company) uses 20A IEC connectors and provides 12/3 cables with them - but that is specialty stuff as well.

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 06:47:54 pm
content: Of course you're not going to find an industrial cord from consumer suppliers! What did you think? And of course you're going to build one - just like everyone else has to build one for that ampacity rating. It only takes a few minutes, so I don't see what the big deal is. Just go to your local electrical supply house, buy it, and be done with it. I'm even able to find decent connectors at Home Depot these days. The new connectors are so easy to terminate, a rhesus monkey could do it.And if you're having that much trouble stripping the jacket off, you're not doing it right. Bend the cable where you want to cut, then just touch it lightly with the blade. The jacket will split nicely without harming the wire insulation underneath. Do that around the circumference, then peel off the jacket. You may need to do a length-ways slice if you're stripping off a long piece.Your wire stripper is dull. Throw that one out and get a proper one from Ideal. I think you can get them up to 10 ga or 8 ga. If you're stripping with dikes, you're almost certainly breaking the strands in the process.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 06:50:14 pm
content: Quote from: rx8pilot on December 18, 2014, 06:46:58 pmI was saying, "Amen brother!" all through your first paragraph. Then I started the second one and. I guess I've become a cable snob...

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 06:51:47 pm
content: Quote from: Monkeh on December 18, 2014, 06:43:08 pmBuy am I alone in my little OCD voltnut world or do others share this opinion?

author: free_electron
author_rank: Super Contributor
timestamp: December 18, 2014, 06:53:05 pm
content: http://www.l-com.com/power-products-power-cordshttp://www.stayonline.com/15-amp-power-cords.aspx

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 06:53:24 pm
content: This is what I use for nearly everything save for Romex:http://www.idealind.com/prodDetail.do?prodId=stripmaster_wire_stripper&div=3&l1=wire_strippersTwo sizes will cover nearly every type of wire you will run into, save for 1/0, coax, etc.... They're $45 each on Amazon and worth it.

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2014, 06:55:41 pm
content: Quote from: SharpEars on December 18, 2014, 06:51:47 pmI appreciate quality cables where needed.Fixed equipment sat on a bench need not apply.

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 06:56:02 pm
content: Quote from: SharpEars on December 18, 2014, 06:51:47 pmYou're alone. Save for ampacity requirements like your 20A situation, I hack the $3 pre-molded IEC cables all the time and have had I think one bad cable over many years. The cables may be from China, but are largely safe and reliable.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 07:11:32 pm
content: Quote from: LabSpokane on December 18, 2014, 06:53:24 pmThanks for that! I just bought the #8-#12 wire version from Amazon. Let's see how it works out on the 12/3 and 10/3 I need to strip.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 07:12:47 pm
content: Quote from: LabSpokane on December 18, 2014, 06:56:02 pmBuy how do they go with your expensive suit?I suppose I am just being silly - form over function...

author: rx8pilot
author_rank: Super Contributor
timestamp: December 18, 2014, 07:18:19 pm
content: Quote from: SharpEars on December 18, 2014, 06:51:47 pmI simply have to choose my battles wisely. I made/used awesome cables because there was no other option in the portable entertainment world.Now, I design mechanical and electrical products from concept to sales. Solidworks to 5 axis CNC, schematics to software. My only chance of survival is to not worry about things that do not directly contribute to a finished product. If the crappy AC cables were causing problems in my lab, I would replace them in a second. They annoy me when I am trying to neatly arrange things with strangly little cables, but they are at least dong the job. Apple notebook supplies use good supple cable that I appreciate, then again - they charge for it.

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 07:38:11 pm
content: Quote from: SharpEars on December 18, 2014, 07:12:47 pmFor the power draw of that supply, don't skimp on the cable. By the same token, make sure you're not plugging that sucker in some some crappy 16ga Romex or worse, knob and tube wiring.The industrial grade cords are gold ... in industrial situations where they will see lots of flex, liquids, solvents, abrasion and general abuse. For something that just sits static on a bench, I just don't worry too much. The prefab China cables really are up to the task.I hope I didn't come off too harsh. I have had the opportunity to "apprentice" next to electricians that knew a thing or two over the years. What we know as EE's is very good and valuable, but the tradespeople have skills worth knowing as well. If you get the chance to shadow a journeyman electrician, do it.And once you get used to the Ideal wire stripper, you'll never go back. The trick is to actuate the handles fully in order to release the wire gripper after the insulation is removed. You just have to trust its automagicness.

author: mstevens
author_rank: Regular Contributor
timestamp: December 18, 2014, 08:26:47 pm
content: I am really amazed by some of the things people say. Can anyone making a claim that $X dollars which is greater than, IMHO opinion, say $1.00 justify this empirically, using some math and science?I don't remember the name of the place but there was a A/V Tech Store in Chicago that use to do a talk show on a A.M. station that use to convince people that they needed a $100 to $200 power cable to get the highest fidelity from their A/V equipment. I think they went out of business... well at least I listened as they were saying the would no longer be doing the show; they my still be in business.I know a little bit about power. I know an understand the computations behind sizing cables. As I am always eager to learn, can someone explain to me via math, and say material sciences, exactly why you have to pay anything more than $1.00 for a power cable?I have worked in extremely large computer labs, data centers, and networking environments. And the power cables that say Network Vendor A, B, C, and Computer Vendor A, B, C, all seem to run the equipment just fine; all generic power cables.Can anyone do the math for me? I would like to know what I am missing. I think to be convincing the empirical proof should include stuff like stranded versus single conductor, resistivity of the conducting material, diameter of the conductors used, spacing between the conductors, number of conductors used, skin effect, etc. l would love to see that empirical proof; as it would completely disprove what I know and have learned.To the OP. Go tell someone who is selling those $100 power cables that you would like to take one home and try it, comparing it to other cables, in your environment. Get then to stipulate that if you don't like it for any reason you can return it, after all it is a power cable, there is no wear and tear on it <laugh> right?... See if they'll go for that. Charlatans!!!

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 08:53:54 pm
content: Quote from: mstevens on December 18, 2014, 08:26:47 pmDear mstevens, I realize that I am teetering on the edge of audiophoolia here, but bear with me if you will. I am not promoting $100 cables with really cool woven insulation, hospital grade connectors (and little else). Oh wait, I forgot cryogenic freezing.Before I start on the empirical proof part of your comment, I just wanted to emote a tiny snicker at the fact that a bunch of audiophools/snake oil salesmen were advertising super duper audiophool power cables on AM radio, no less! I mean the people who listen to AM radio most likely are not using the most expensive audio gear and it would be pretty hard to convince them to add a $100 power cable to their ancient worthless AM radio.Now with regard to the empirical stuff, you will agree that powering 120 V / 1875 W stuff through an 18 AWG power cable, especially of great length, is a bad idea, yes? Also, if you are running your cable connectors on the floor in a basement, would you agree that some level of moisture resistance (e.g., in case there's a flood, etc...) may be a good idea? Finally, if we were to use say a decent length 10/3 or 12/3 copper (and not CCA) cable with a decent plug, would you agree that the copper alone would cost more than a $1 and therefore the cable cannot be sold for the same price as 18/3 Wun Hung Lo crap? This is not to say that it should cost $100, more like say $20-$25 for a ten foot 12/3 cable with quality plug/receptacle termination, assuming very inexpensive labor costs, since the plug/receptacle needs to be attached by a person and that takes time.Having said all of that, I am not making any sort of audiophool electrical claims with regard to noise, skin effect, yada yada. I am only trying to reduce losses and decrease heat by suggesting lower gauge conductors for high power circuits such as my power supply which has a maximal power requirement of 2,600 W. I am also a fan of 12/3 and 10/3 for long extension cord length and by long I mean 50-100 ft or more. That and perhaps a bit in the cosmetic department of the whole setup looking nice is all I am saying.

author: aroby
author_rank: Regular Contributor
timestamp: December 18, 2014, 09:05:05 pm
content: The consumer cables aren't great, but you can buy decent cables without having to spend a fortune. I bought 4 fairly short custom cables for my server rack fromhttp://www.stayonline.com/.The quality, in my opinion, is excellent.Anthony

author: rx8pilot
author_rank: Super Contributor
timestamp: December 18, 2014, 09:06:27 pm
content: I still have some super fine "stingers" as we call them. 12/3 SO cable with Hubbell for use as extension cords. I am the first to say.... They make me feel better. I throw them out and they flop nice and flat on the ground. I dont care so much about electrical superiority, but they are nice to have. Would I choose to build them today for use in my lab or house? Probably not, but only because I don't have the time.

author: electr_peter
author_rank: Unknown
timestamp: December 18, 2014, 09:14:52 pm
content: If you are at least a bit serious and care about quality and safety, you should check mains cables you use and buy proper cables. Or make them yourself from quality parts.For low power devices I have not had any issues with 2 pin cables, but 3 pin cables for more powerful devices can be of dubious quality. Usually I buy quality plug with cable or plug and cable from electronics shop and make final connection myself. By buying incomplete cable you can at least see quality of the wiring and insulation.Some general tips for checking mains cabling:Outer insulation should have a stamped/printed marking matching internals. If not marked, buy only from marked reels at serious dealer.Check cable bending and insulation physical properties. Check that it is stiff enough for cable diameter.Get a strong magnet and check cable plug, cable socket and cable itself for magnetic attraction. Any attraction -> some ferrous (steel) parts -> crapIf possible, check metal diameter in cable. It should be big enough. Check continuity and resistance with mili-Ohm meter. Too high resistance -> cables are too small.Check outer and inner metal wiring composition. Outer should have silver(aluminium or plated copper) or copper color. Inner should be copper or aluminium metal. Some cables are from steel -> crapI found some videos about cheap extension lead (UK lead, but applies to all countries). That POS broke Guinness world record for the crappiest quality possible, especially concerning mains cable. I was amazed how cheap and dangerous fake mains cable can be.

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 09:19:28 pm
content: Quote from: rx8pilot on December 18, 2014, 09:06:27 pmAnd you can run them over with a vacuum many many times and not even consider the possibility that you ate through the insulation. As a bonus when Spot gets hungry for some plastic with his Kibbles and Bits, he won't get electrocuted.

author: kingofkya
author_rank: Regular Contributor
timestamp: December 18, 2014, 09:33:00 pm
content: Quote from: free_electron on December 18, 2014, 06:53:05 pmI second that one and mono price for cheapness, i work in a data center and have yet to have power cables from ether company break.Also as a side note if you have pdu with IEC320 C13 one em aka 204-220v ones theses are the best investment you can make to stop power cords from disconnecting from poor connector tolerances. and vibration.http://www.stayonline.com/searchresult.aspx?categoryid=3593

author: free_electron
author_rank: Super Contributor
timestamp: December 18, 2014, 09:42:27 pm
content: Quote from: SharpEars on December 18, 2014, 08:53:54 pmbah humbug. keep the signal in digital bitstream format all the way just prior to the speaker and then use a class T amplifier to drive that. no need for shielded cables. a coathanger will work just as well ( as has been demonstrated )

author: SharpEars
author_rank: Unknown
timestamp: December 18, 2014, 09:52:45 pm
content: Quote from: free_electron on December 18, 2014, 09:42:27 pmBut what about the skin effect attenuating all those high frequency 1 bits to 0.999. And the jitter, it's all about the jitter! I see you have at least a femtosecond of it there even if I can't measure it and that's definitely audible, just listen with your (golden) ears. Btw, is your coathanger made from multiple thin strands of pure 6-nines silver individually insulated with teflon foam and woven into a symmetrical hyperlitz arrangement then terminated with rhodium plated OFC 6-nines copper connectors with the entire thing then cryogenically frozen for a week and finally broken in for at least 100 hours using a proper Stereophile break-in disc? Otherwise, it's obviously audibly worse and there's no point in even listening to music through it, especially the supreme 192kHz/24-bit sampled music I play straight from WAV files not to hear the lossless compression artifacts that APE, wavepack and FLAC definitely add from the extra CPU load of on the fly decompression during playback.If only I made this upand it wasn't the actual real world state of audiophoolia...

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 10:33:53 pm
content: Quote from: free_electron on December 18, 2014, 06:53:05 pmOh and the l-com link that free_electron provided is where I bought my last batch of IEC cords on closeout. I think they were a whopping $1 or $2 each. They have the same ones I bought, but in brown for $100/100. What I received was a quality mains cord for a great price. No complaints.As a side note, I really cringe at all the "Wun Hung Low" swipes that are made on this board. It's really turned into a racial slur. I've bought quite a bit of bits and pieces from Shenzen lately, and everything has been good quality with good service. It's really unfair to rail on the Chinese like what I see on here. I've actually had more problems "buying American" lately when it comes to electrical stuff than I have direct from China. Same goes for the power cords. What I've received is quality product. Wun's doing just fine if you ask me.

author: Macbeth
author_rank: Super Contributor
timestamp: December 18, 2014, 11:44:07 pm
content: SharpEars - thank you, this is an issue close to my heart. It is unbelievable how shoddy IEC cable has gotten. I have an account with a company in Cheshire, and every time I go and pick up some consumer tat from Argos, Tesco or ASDA, I throw those disgusting mains cables in the trash.I highly recommend the Nordost Valhallahttp://www.cheshireaudio.co.uk/acatalog/copy_of_Nordost.htmlas the ultimate mains lead.Now you maybe a cheap arse and only pay £2199.99 for the 1 metre lead, but I have found my tea tastes better since I upgraded to the £3999.99 lead that lets me position my kettle 5 metres away from the dangerous radiation of the plug sockets. There's lots of cable to wrap in plenty of tin foil too.

author: -jeffB
author_rank: Regular Contributor
timestamp: December 18, 2014, 11:54:46 pm
content: Quote from: aroby on December 18, 2014, 09:05:05 pmOMG!10-15 years ago, Stay Online was a local parts store that sold odds and ends -- connectors, cables, adapters -- that you'd otherwise have to mail-order. Prices were very steep, but they were a godsend for local tech startups that found themselves with just the wrong kind of SCSI cable.I noticed some time ago that they'd disappeared. I had no idea that they'd found a second life as a cable manufacturer.

author: macboy
author_rank: Super Contributor
timestamp: December 19, 2014, 12:31:53 am
content: Quote from: SharpEars on December 18, 2014, 05:35:49 pmYou already have ~100 feet of 14 AWG cable in your walls between your panel and the outlet; is another 6 feet of 14 AWG cable between the outlet and the device really so bad? Will 6 ft of 10 AWG make a positive difference?

author: SharpEars
author_rank: Unknown
timestamp: December 19, 2014, 02:33:35 am
content: Quote from: macboy on December 19, 2014, 12:31:53 amI thought that 12 gauge was used all throughout the house because the runs from the mains are in excess of 50 feet.

author: Someone
author_rank: Super Contributor
timestamp: December 19, 2014, 03:47:42 am
content: Quote from: HighVoltage on December 18, 2014, 04:35:41 pmIt has been a while since I read the standards for Australia but as I recall you could ship a product with a mains plug to C13 cable and it only had to match the current rating of the equipment it was shipped with, we weeded out all the odd rated cables from stock and left only 10A rated ones to avoid confusion from users (who were so stupid they couldn't avoid electrical fires).

author: Corporate666
author_rank: Unknown
timestamp: December 19, 2014, 05:22:12 am
content: Quote from: SharpEars on December 19, 2014, 02:33:35 amShould be 12ga wire for 20A outlets in a residential building.But I don't really understand the original criticism of power cables. eBay is always going to be pretty much the worst place to buy anything specialized and high quality. People don't need 12/3 power cables with hand assembled clamp-together NEMA connectors for their LCD monitor and their XBOX, so you're not going to find those specialized wires at mass-market outlets anymore than you will find QFN microcontrollers sold individually at Radio Shack. The market just isn't there.I actually prefer overmolded cables of sufficient gauge because they seem much more durable. But if you want a cable that is not mass producible, then you're never going to find it mass produced. You'll always need to either make it yourself or go to a specialty place who will make it for you (and charge for that). Stayonline.com will do it for $60 per cable with the 12/3 wire and NEMA screw together connectors you like. Or you can buy it molded for $10... your choice.