Proper network cable splicing

[Pastor Tim]

Back in February we had a small fire in our church Fellowship Hall. Part of the damage was that the data lines running between the buildings were burned off inside the Hall. The electrician our contractor hired assured me that they knew what they were doing, but after the way they spliced the cables I'm a bit unsure, I've never seen cat 5e spliced this way. (The fact that they just pulled new wire in without labels or organization doesn't exactly instill confidence either, but that's something I can work out on my own.)

So, does this look like an appropriate way of splicing Cat 5e used for full-duplex 100TX data?

[sadlerjon]

Originally Posted by Pastor Tim

Back in February we had a small fire in our church Fellowship Hall. Part of the damage was that the data lines running between the buildings were burned off inside the Hall. The electrician our contractor hired assured me that they knew what they were doing, but after the way they spliced the cables I'm a bit unsure, I've never seen cat 5e spliced this way. (The fact that they just pulled new wire in without labels or organization doesn't exactly instill confidence either, but that's something I can work out on my own.)

So, does this look like an appropriate way of splicing Cat 5e used for full-duplex 100TX data?

Tim -

The EIA/TIA 568 specs are quite clear - you're not able to untwist a cable for more than 1/2 an inch and still keep Cat 5/5e rating. Also, Scotch-lock connectors are not Cat5 rated.

At a minimum, the two cable ends should be terminated on an IDF (Intermediate Distribution Frame), occupying two positions on a 110 block and with a Cat5 rated jumper between them. Alternatively, the two cables could have been terminated on RJ45 jacks with a short RJ45 patch cord between them.

When I have an installer put in Cat5/5e cable, I always require that they perform certification tests of the cabling (using a tool such as a Pentascanner) and provide me with a binder of the test results. I don't believe the installation you are showing would ever pass such a test.

[petereit]

Fire him. Immediately. Completely incompetent. I hope you haven't paid him any money.

What caused the fire?

[FlamHappy]

Crimp new RJ45 connectors on the ends of the cable at the splice then use an RJ45 coupler to join the two crimped ends.

That's how it's done.

[sadlerjon]

Originally Posted by FlamHappy

Crimp new RJ45 connectors on the ends of the cable at the splice then use an RJ45 coupler to join the two crimped ends.

Generally, RJ45 plugs are only used on patch cords that go from a wall jack to a computer. The wire used in patch cables is stranded wire (that way it is flexible). Horizontal cable uses solid wire. This creates a problem when crimping plugs onto horizontal cable - the plugs for stranded wire (which bite through the wire) will not maintain a reliable connection with the solid wire. RJ45 jacks on the otherhand have a v-grove which provides a gas-tight connection (reducing resistance/loss) -- which is why they are used on the end of horizontal cables.

While RJ45 plugs do exist for solid wire, they are not commonplace and manytimes require specialized dies for crimp tools. This is why I reccommended either placing a 110 block or putting jacks on the ends of the cables.

[FlamHappy]

RJ45s come in two flavors. For stranded cable and solid. Just get the right ones.

I have crimped solids over and over with my good old crimper. Works great.

[Pastor Tim]

Pretty much sounds like my first thought was correct. I had thought about a 110 block or just putting plugs on and a connector. I assumed that an electrical contractor who is supposedly certified for network installation would know what to do. I'll have a little chat with him. This electrical contractor was not my choice, but is the guy our general contractor normally uses.

The fire was started by someone backing into the electrical meter, which caused a short to the conduit which blew up a light fixture in our attic storage area. It was really a pretty small fire, but we are already over $60,000 into repairs and cleanup. Amazing how it stacks up.

Pastor Tim

[rkresge]

Originally Posted by Pastor Tim

Back in February we had a small fire in our church Fellowship Hall. Part of the damage was that the data lines running between the buildings were burned off inside the Hall. The electrician our contractor hired assured me that they knew what they were doing, but after the way they spliced the cables I'm a bit unsure, I've never seen cat 5e spliced this way. (The fact that they just pulled new wire in without labels or organization doesn't exactly instill confidence either, but that's something I can work out on my own.)

So, does this look like an appropriate way of splicing Cat 5e used for full-duplex 100TX data?

I'll add my $.02 worth here.

NO! Cat 5 (including 5e) may NOT be spliced this way. The specs allow two cross-connects, one at either end, usually in the form of a patch panel or a wall plate, to transition to patch cables. Buried deep in the specs there's also an allowed intermediate cross connect, but you DON'T do it by untwisting the pairs and using wire nuts. After any work you should also get professional test results from a high-end pair scanner, which that puppy is not about to pass.

However, it's worth keeping the photograph for laughs! And examples of how NOT to do things. Even more fun is the very real possibility that the cable may actually appear to work! But it will be generating all kinds of errors that you may not see without high-end networking equipment.

Roger

[petereit]

LOL! Yes, that cable will still "work". Just like how LA freeways work during rush hour.

[tedanderson]

Electricians are NOT data cabling installers. Most of them think that there isn't anything special about CAT5 and the general mindset is that it's just wire.. just like any other low-voltage wire that they would use for a doorbell or a phone jack.

Based on that photo, I would have let it slide provided that he didn't untwist the wires that far prior to terminating it with the 3M's but none the less, that is a very very very improper CAT5 splice. If anything, the cable should be replaced completely from point A to point B because the heat from the fire could have compromised the integrity of the cable even if there wasn't any visible fire damage elsewhere within the facility.

[Pastor Tim]

Final update on the wiring.

I ended up not re-doing the splice because the electrician wouldn't and I didn't feel like lying on my belly in an 18" crawl space to re-do it. They promised that if any problems showed up they would come out and do it my way.

Not having access to any sophisticated test equipment all I can do is check for dropped packets and comm speed, both of which seem to be OK. I'm not real happy about it, but until it gives trouble I'll just ignore it.

I thought about re-pulling the entire run, but it would have required digging up conduit across the yard and a lot more crawling under buildings and through attic spaces than my body is good for. The splice point is well removed from the fire damage and there is no sign of heating on the wires, so I think from that perspective it will be OK. Meanwhile there are developments afoot that may make the whole discussion moot from my perspective.

Pastor Tim