I received a edexcel patch panel for a cat6 ftp cable, I was puzzled by the diagram. It shows I should cut away the foil. I am used to pulling the foil back and placing it under the bar clamp.

Is it ok to cut away the foil and just punch down the drain wire ?

2 Answers 2


Depending on the clamp size and form, it may be necessary to remove insulation for a clean fit. Otherwise it's fine to clamp over foil and outer insulation.

  • The bar clamps down on 8 cables at a time. The bar screws down just into the case it is not grounding to the the external ground wire, just the outer casing. From what i can see the screws that go into the bar are wpainted thus it makes me think that if i did pull back the foil, only each of the 8 cables ground to each other Jun 26, 2017 at 19:08
  • The casing is grounded, right? Otherwise you'll need to connect it to ground.
    – Zac67
    Jun 26, 2017 at 19:17
  • It has a ground wire on the case ready to attach to your earthing point Jun 26, 2017 at 19:19
  • I think since the foil is to stop interference it not so important as the drain wire for grounding. Jun 26, 2017 at 19:56
  • 2
    For the shield to work correctly, it needs to grounded. If you've got problems with the electrical potential between both endpoints it may be better to NOT ground one side - the compensating current may cause interference and noise in the cable.
    – Zac67
    Jun 26, 2017 at 20:00

Since Category-6 is specifically UTP (Unshielded Twisted Pair), then the question of shielded Category-6 cabling doesn't make any sense. ANSI/TIA/EIA define the cable categories, and there are no cable categories defined except for UTP.

The ISO/IEC defines cable classes, and it has defined several classes that employ a shield.

Having said that, many cable manufacturers will offer a shield on their cable to try to make up for poor cable performance (would not pass the test suite without the shielding). If shielding is used in cabling, it must be continuous from end-to-end, with no breaks, and grounded, at least, on both ends. The equipment on each end must also be compatible to ground the shield.

There are documents that explain things for you. For example, Shielded and unshielded twisted-pair cable revisited:

If STP cable is combined with improperly shielded connectors, connecting hardware or outlets, or if the foil shield itself is damaged, overall signal quality will be degraded. This, in turn, can result in degraded emission and immunity performance. Therefore, for a shielded cabling system to totally reduce interference, every component within that system must be fully and seamlessly shielded, as well as properly installed and maintained.

An STP cabling system also requires good grounding and earthing practices because of the presence of the shield. An improperly grounded system can be a primary source of emissions and interference. Whether this ground is at one end or both ends of the cable run depends on the frequency at which a given application is running. For high-frequency signals, an STP cabling system must be grounded, at minimum, at both ends of the cable run, and it must be continuous. A shield grounded at only one end is not effective against magnetic-field interference.

  • It doesn't' t actually answer the question. I'm debating the fact of whether foil should fold back ? There are cases where the drain wire would wrap around 4 copper core wires with foil stripped back entirely before insertion into a shielded RJ45. Getting back on point, since the leaflet does not indicate that the foil should be used I'm leaning towards stripping it off . It refers to the braid being used for ground, and since i have a drain wire rather than an braid i will use that for grounding. If I had both i could fold back the foil and wrap the drain wire around the foil. Jun 26, 2017 at 22:58
  • It does answer the question. Folding the foil back damages the foil, "if the foil shield itself is damaged, overall signal quality will be degraded.". The connectors must be shielded connectors, and they accommodate the foil (or braid for braided, rather than foil) cables into the connector. You do not want to expose the pairs without the foil. The drain wire is not shielding.
    – Ron Maupin
    Jul 2, 2020 at 17:38

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