Unconnected Drain Wires ?


I have seen some power cables for sale here that have unconnected drain wires.

What is a drain wire?

Why do they disconnect drain wires on some cables, but not on others?

Does an unconnected drain wire present a hazzard?

Thank you.
mmarvin19
What is a drain wire?

The ground wire. You have three wires, hot, neutral and ground. Some refer to the ground wire as the drain wire.

Why do they disconnect drain wires on some cables, but not on others?

By eliminating the ground wire, you can eliminate the chance of a ground loop hum. Search the archives for more information on ground loop hums.

Does an unconnected drain wire present a hazzard?

There is a possibility that it could be potentially dangerous. Most feel that using one ungrounded cord in a system, say on a source that is experiencing a ground loop hum, is acceptable, as long as the preamp cord is grounded. The theory being that a electrical malfuncuntion could travel through the interconnect and find the ground through the preamp power cord. A system with all ungrounded power cords is DEFINITELY dangerous, and should be avoided at all cost.

Cheers,
John
I'm using power cable (CryoMax III) that hasshielded hot/neutral/ground wires AND a separate unshielded drain wire. This may be what the OP is talking about. Various discussions on AA's Cable Asylum recommend attaching such drain wires at the source end, the other end, both, or neither. It would be nice to resolve this issue, if there is a resolution. Dave
Dopogue, I agree with you... It means the shield of the cable is floating, not the safety equipment grounding conductor.

Shunyata's Diamondback shielded power cable and Venom shielded power cable both have their drain wires lifted at both ends of the cable.

Because Shunyata power cables are UL/CSA Listed cables Shunyata is required by UL to have a label on the cables that tells the consumer the drain wire is not connected to either end of the cable. Again it has nothing to do with the safety equipment grounding conductor of the cable.

By the way a shield on a power cable does not have to be grounded to reject RFI/EMI.
I guess I stand corrected. I've seen shielding drain wires on interconnects, mostly phono interconnects, and some speaker cables, but I've never seen a shield drain wire on a power cord. Live and learn.

Thanks,
John
The Belden 19364 cable which is used in the DIY Bob Crump designed 'Asylum' power cord has hot, neutral and ground wires, plus a metal foil shield and a separate drain wire.
Disconnected drain wire is not a safety hazard but it is not a good idea as the now floating shield will act like an antenna. If you are using a shield design always connect the drain at the wall side only.
.............. but it is not a good idea as the now floating shield will act like an antenna.If you are using a shield design always connect the drain at the wall side only.
03-11-09: Cpk

Cpk, I use to think the same way.... But how do yo explain the two Shunyata power cables I spoke of in my above post?
Hi Jea48,

Since that is not my company I luckily don't have to explain it ;-), maybe they like the radio stations in Poulsbo, WA? I have heard before that that is how those lower end shunyatas are configured but I was unable to find that actually spec'd anywhere, maybe I am looking in the wrong place. Perhaps in certain system/situations an unconnected shield sounds better but you always run the risk of it acting like an antenna. In general connecting the drain to the wall will give you the best sound on a shielded cord in the vast majority of system.
In general connecting the drain to the wall will give you the best sound on a shielded cord in the vast majority of system.
Cpk

Cpk, thanks for your response.
As I said in an earlier post my understanding of connecting the shield to the source end of the power cable is to bleed off RFI to earth ground and stop the shield from acting like an antenna.

Then I ran across the Diamondback shielded power cable. I borrowed one from a dealer in my area and tried it on my CDP. Not a bad power cable for the price.

At any rate the drain wire is not connected at either end of the cable. And as far as I know no one has complained about RFI problems.

And here is some food for thought.... How about audio systems out there with shielded power cables that have a ground cheater/s connected to them because of a ground loop hum problem? Or systems connected to an old two wire house electrical branch circuit without an equipment safety ground.
Though in the case where an equipment safety ground is not being used there would still be a conductivity path back through the equipment grounding conductor of the power cord to the equipment chassis signal ground,... but not earth ground. Wow, LOL.... What is your opinion on that one...
Jim
Hi Jim,

What I make of it is everyone’s system and situation is different. If the weren't it would be much easier to design a line of cables that work well in all cases. For example Mr. Hansen of Ayre fame IIRC runs with all the grounds lifted on all his gear, if you search Asylum there are a number of his posts concerning this. He says sonically it is superior. I run with all my frontend floating and my amps grounded but then again none of the cables that I make are shielded and I have no problem with noise or hum.

What I heard when listened to a cord with a floating shield was a reduction of air in the soundstage, in a system that these level of cords may be used in that might translate into a reduction of some HF nasties
Yes Charles does float his entire system (and his older home has ungrounded outlets) but it is also worth noting that Ayre double insulates their component chassis' thus making the endeavor safer.

Chris, I was thinking of floating the ground on my front end by disconnecting the components internal ground wire, rather than doing it at the AC plug end on my Tel Wire cables. Any thoughts on this? If I had to do it on the AC plug end of the Tel Wire cable is it easy enough to do?
Hi Tony,

My suggestion would be turn off breaker feeding that outlet then just disconnect the ground at the receptacle. You could do it at the AC plug but I don’t think you want an unconnected ground wire flopping around in the plug body. Hey what length speaker cable do you use?
I thought about doing it at the receptacle, but someone told me it was better to do it at the component IEC, which I can understand, just don't know what other hazard it might create. I'd definitely prefer not to take apart a cable, especially yours.

Currently using a 5' pair of Grover Huffman speaker cables. Why do you ask? So as not to hijack the thread you can email me offline on this.
For example Mr. Hansen of Ayre fame IIRC runs with all the grounds lifted on all his gear...

My understanding all current Ayre equipment is manufactured with double insulated AC power wiring thus no equipment ground is used.

More and more manufactures are moving in that direction. Of course most are doing so to minimize ground loop hum complaints.

I predict with-in the next 5 years all consumer electronics sold in the US will be two wire cord and plug.

Why? New changes in NEC 2008 NFPA 70 code.
Article 210.12

Simply stated:
All 120V 15 and 20 amp branch circuits supplying outlets installed in dwelling units shall be AFCI /GFCI protected. Finished basements, GFCI protected..... Exception Fire alarm system. Of course the AHJ (Authority having jurisdiction) has the final Say. My State adopted NEC 2008 code in February of this year, 2009.

What does this mean if multiple dedicated circuits for audio gear are used? If the equipment uses a safety equipment ground and is connected by ics to other equipment there will exist the chance one or more of the AFCI/GFCI protection units will trip open.

A dealer in my town has already faced this problem with a new HT system he installed in a new home built this year. The cure? He ended up plugging all the equipment into one of the two supplied 20 amp dedicated branch circuit receptacle outlets.
Cpk,
Are you a cable manufacture? Name and web site please....
Jim
Jim,

Chris Kline is a cable manufacturer, here is a link to his website.

Cheers,
John

PS: He is a great guy too.
Thanks John.
Hi Jea48,

I am Tel Wire. I try my best to when I give opinions to not have them not conflict/inadvertently support my design decisions.

Thanks John!
I am Tel Wire. I try my best to when I give opinions to not have them not conflict/inadvertently support my design decisions.
03-12-09: Cpk

Cpk,
No problem there..... My interest was in checking out your web site and your cables.
Jim
As John said Chris is a great guy who is a pleasure to deal with. I'm a satisfied customer and can say the cables are well worth checking out.
Simply stated:
All 120V 15 and 20 amp branch circuits supplying outlets installed in dwelling units shall be AFCI /GFCI protected. Finished basements, GFCI protected..... Exception Fire alarm system. Of course the AHJ (Authority having jurisdiction) has the final Say. My State adopted NEC 2008 code in February of this year, 2009.
I should of proof read my post a little closer before posting it. Someone reading my post might think I was saying an AFCI/GFCI is a dual unit. It is not. They are two entirely different electrical devices and preform two entirely different functions.

I also noticed I mistyped a word in the following statement,
Finished basements, GFCI protected....
It should read;
Unfinished basements, GFCI protected....

Basically what I was trying to say, depending where you live in the US, if you buy a new house built in 2009 (or built in the future) in an area where the AHJ has approved, or will at a future date, NEC 2008 210.12(B) good chance you will be plugging your audio equipment into a AFCI protected branch circuit/s. It is only a matter of time....

In an unfinished basement a GFCI protected circuit or GFCI receptacle.