IPVMU Certified | 03/24/15 05:00pm
In general, splicing should be avoided. Here's why I have this opinion:
1) Twist Rate: Remember the 'TP' part of UTP/STP is an important feature. The specific twist rate of a cable is sure to be disrupted at a splice point, and all the nasty performance impacts you're trying to avoid can creep up at that point.
2) Oxidization: All metal oxidizes when exposed to air. A conductive material like copper will have degraded performance when this oxidization occurs. In short: a splice may not cause performance/bandwidth/speed issues when freshly cut, but over time can disrupt performance.
Splicing, if done right (Hint: never use wirenuts like the image above) may not be a 'showstopper' causing gross malfunction, but it can present a significant bottleneck that should be avoided.
Am I missing others?
If two separate cables need to be connected together (for example, to lengthen a short run) and a new single run is not possible, I would recommend putting jack on one cable and a plug on the other, then connect the two.
This will help keep the integrity of the twists and would serve as a 'better' option than using wire nuts.
As Brian mentions, it should be avoided where possible. But in reality sometimes it cannot be avoided. In these cases I feel the 'jack and plug' method is more appropriate than wire nuts.
Here is an example of a jack and a plug
Ideally, never do it.
That being said, not all situations are ideal. The instances in which I would not do it:
- Cables are being certified and documented, especially for bid projects. The splice will show in tests, generally speaking. Whether or not they're scrutinized that much varies per job, but I've known people who have been caught.
- When repulling it is relatively easy. If you can have another one in to replace the cable in an hour, repull it. Doing things right and fixing mistake is one of the things that separates a real company from a trunkslammer.
That being said, there is something in standards called a consolidation point. I used them in my cabling past in open offices. It's essentially a set of trunk cables pulled to one point, then terminated to a block and patched to another shorter set of cables which serve the area. They're shorter and normally intended to be repulled when offices are rearranged periodically, while the trunks remain in place.
A splice done correctly is really no different than a consolidation point, which is why I can be ok with it in emergencies. How I generally do it is to get a two port surface mount box, like so:
Terminate both ends of the splice to a jack of the type used in the rest of the installation, matching or exceeding the Category rating (Cat5e or 6 on a Cat5e system, Cat6 or 6a in a Cat6 system). Patch them using a factory terminated cable, at least 1' to maintain a decent bend radius.
There are also punchdown splices made for this, but I generally avoid them because they always seemed to be made by cheap no-name manufacturers, and I preferred to use rated components I trust.
This box should be located somewhere accessible. Mount it to a wall above the ceiling, attach it to building steel, etc.
- Hide the splice in a bundle somewhere for someone to find later. Techs everywhere hate you.
- Use wirenuts or beans or 3M crimp connectors. At least try to maintain some semblence of category rating and professionalism.
- Put a jack on one end and a plug on the other and tape them up. Theoretically, it's one fewer connection and should be a higher quality link than two jacks and a patch...but it'll come apart. Inevitably, believe me, it will come apart. And field-installed plugs are much harder to terminate well than jacks.
IPVMU Certified | 03/24/15 06:30pm
Man, I hate those gel filled beanie connectors.
They might work great in your alarm panel, but they have no place in an ethernet network.
Another option, is the Bicsi blessed, Emergency Ethernet Repair Kit
Just don't call it a splice, and you're good to go!
IPVMU Certified | 03/24/15 10:26pm
Sorry, but just because they put a Bicsi image on their power point doesn't mean it is Bicsi approved. It may be, but I have still yet to find proof of that. The link is helpful thank you for posting it. I agree with your comment, they are trying to re-define/water down the definition of a consolidation point to justify their splice product.
...it is very bad practice to repair cables in the horizontal like this, as there is definitely be loss and potential other effects from the connector/splice. Jeff from Bicsi
Here's what I don't get: Does he mean even when the splice is done as well as possible, that there will be a significant loss/adverse effects seen at once? If it tests ok, is it ok? Or is the real problem down the road, due to oxidation, like Brian suggests?
The reason I ask is because it doesn't make sense to me why the splice would be any worse, signal wise, from a jack and plug, like Matt suggested.
But if the insertion loss from a jack and plug is significant, why does Bicsi generally recommend the extra jack/plug/patch camera side?
IPVMU Certified | 11/02/15 05:21pm
Standaards define 4 up to 6 connector Channel Models. Depending On the nummer of connections you allready have in Youri channel, the splice might be the one to many as standaards are concerned.
As Ethan mentioned, one is ok why not two etc etc? Because in the end you won't know how many you allready got in place. Unless you al guys document you're installaties better than 90% of all Cabling installers...which i honestly dear to doubt (forgive me my lack of confidence here ????)
Bottom line, if iT tests ok iT schold werk without problems sure enough. Ever tried to make à Cat.7(a) link fail on for instance a Fluke DTX1800 tester? I have and iT took me four knots in the cable, a desk On one of the knots and me jumping On iT several times before iT failed. Ok, the test passed with 'only' the knots in the Cable but i wouldn't want that in my installation.
So in my view, stick to the standards, test and...hope for the best
Surely it depends on the reasons driving the decision. As a permanent installation - of course not. As a temp fix during a late night service call - maybe. Plug and jack method would be the preferred route.