Power cable construction/shielding

Filipedine

Hi,

I have Keces Power conditioner BP-2400, and recently decided to buy a power cable to improve the safety , reliability and reduce interference, this power cable it to be used from mains to the BP-2400. The cable I purchase has a shielding layer, however when i look at the plugs, the shielding layer is not  connected to the ground wire.

I was under the impression that for the shielding layer to be effective (metal foil around the 3 wires ground, neutral, and hot), the shield layer should be connected to the ground wire at both ends, is this correct?

Many thanks

Filipe

noiseboy72

The shield need only be connected at one end. In fact, if you connect at both ends, you can get eddy currents that add hum.

Shielding is not normally required for mains. It is unlikely it will accept interference from an outside source and the electromagnetic field it creates is extremely limited in range due to the cancellation effect of the hot and cold running in parallel. If the cores were twisted, there would be practically no EMF whatsoever.

dannnielll

No. A shield has to be connected at one side only..If it is connected at both ends it becomes  a conducting wire carrying a current. Now I would  have little respect for a number of these mains conditioners..

Filipedine

Hi,

I am very happy with the keces BP-2400, and the conditioner is not causing any issues. What I am trying to asses is if the new power cable I have could/should have the shielding connected.

Makes sense what you are telling me in terms of only one end being connected to the ground wire. I also understand the reason for it to not have been done, but if one had the chance of having 2 equally built cables where one have the ground connected and the other doesn’t,witch one would be a better choice?

Filipe

noiseboy72

A fully floating shield will just upset the capacitance of the cable at high frequencies and will act as an antenna for certain frequencies of RF. There really is very little point in a cable of that type.

The shield can be connected at either end, but not both.

larkone

You will find that your (expensive?) shielded cable will sound exactly the same as a standard lead and give no benefit other than to the profits of the manufacturer

RBZ5416

You want to improve the safety & reliability of a mains cable?

BlueWizard

Regarding Shielding in a Power Cable, remember that on the other side of that electrical outlets are many meters of unshielded cable back to the Fuse Box, and many miles of unshielded wire back to the source.

Hard to see how 1 meter of shielded Power Cable could make that much difference.

Most Power Cables are THREE Wires - Hot, Neutral, and Ground; in some cases - Hot, Hot, Ground, but the Ground is a Earth/Chassis Ground and should never carry any voltage or signal. So, it should be OK to attach it on both ends, though attached at the Outlet end is also workable.

Most ground loops are cause by a voltage difference between Grounds, but those are Circuit/Signal Grounds, not Earth/Chassis Grounds. Again, there should never be any voltage on the Earth Ground, if there is, their is something wrong with your circuits.

There might be some value to getting a better, preferably heavier Power Cord, but just because the cord is physically bigger does not mean the wire inside is bigger. There is also value in heavier duty Power Connections. Cheap general merchandise store electrical connectors are just that - Cheap. Plugs/Sockets that are hospital/commercial/industrial grade have very tight connection from the stronger internal contacts. So, there is value in those extra tight connections.

But Fancy Power Cords are a high profit center. A basic cord that is dressed up fancy with FAT Insulation can command an outrageously high price based on appearance and perception alone. Yet deliver no more value than a common Power Cord.

But it is not the cosmetics of the Power Cord that matter, nor is it, for the most  part, about how fat the insulation is, rather it is about the quality of the connectors and the actual size of the conducting wire itself. Fat wire with thin insulation is better than fat insulation with thin wire.

So, my point is, if you buy or build a fancy Power Cord, know what you are getting, know what is actually important. Don't confuse pretty for practical.

Also, on the Power Conditioner End, what type of Plug-In does it have? 2-wire, 3-wire? I suspect it is a standard 3-Wire IEC Power Cord -

                                                                                                                                                                                                        DTK power cable, 1.8m power connector IEC 320 C13 H05VV-F cable, 3 pin IEC power cord for printer, PC, monitor, TV, beamer, PS3 / PS4 PRO, DJ equipment, stage equipment, black: Amazon.co.uk: Electronics                                                                                                        Free delivery and returns on eligible orders. Buy DTK power cable, 1.8m power connector IEC 320 C13 H05VV-F cable, 3 pin IEC power cord for printer, PC, monitor, TV, beamer, PS3 / PS4 PRO, DJ equipment, stage equipment, black at Amazon UK.                                                                                                                                                                                                        www.amazon.co.uk                                                                               
If that is what you need, make sure that is what you get. I'm not recommending this specific cord, just using the photo.

Remember, if you are not getting a cable with larger conductors and more heavy duty connectors, then all you are buying is cosmetic appearance.

And ...reasonably... don't spend a fortune.

Steve/Bluewizard

dannnielll

Sorry Steve, but a shield is only intended to be connected to earth or a voltage point at one end. The intention is that there should  be an electrostatic equipotential  conducting surface covering the sensitive electronic terminal . If connected at both ends   it can contribute to an earth loop. An Earth loop need not be intended to carry current, but the magnetic field of the earth, altered by  the presence of a ferromagnetic entity...  As simple as A truck passing in the street outside  will induce a voltage in the loop and this can be picked up.
The other point ,you make that there is literally hundreds if not thousands  of miles of unshielded power cables which does not affect  other equipment including incredibly important fetal heart monitors seems to have escaped the attention of a class of audiophile.

BlueWizard

For an Earth Shield  yes, but not for an Signal Shield, and given that the connection of an Earth Shield is, for all intent and purposes, an Earth to Earth Connection, the potential for a ground loop is slim unless the house wiring is faulty.

If a preson is intent on doing this, I urge them to understand what they are getting and what the cable ACTUALLY does.

Steve/bluewizard