# Data and cable jobs



## kb1jb1 (Nov 11, 2017)

If dropped ceiling then keep everything off the grid. NEC does require spacing which I thought was 6 or 8 inches. I worked in a building years ago where everybody was complaining about the server and the IT department. It was the guy who ran the DATA cables and the guy who wired the building. Lighting was 277 volts and done with romex ( NM) cable. Everything was tangled together. If using Cat 6 cable, check the specs on it. Some Cat 6 plenum is about $325.00 / 1000 feet and some is over $750.00 / 1000 feet. Also be aware if using PoE. The cable is limited to the watts it could carry.


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## SWDweller (Dec 9, 2020)

Part of the answer about separation is answered when you use shielded or non shielded wire.
I just put 2500 feet of shielded cat 6 in my new home. House is all metal. When I was installing a lot of CAT wire, we found shielded wire was less likely to get get cross talk or interference. The 12"+ rule is an absolute if your any where near medium voltage or high frequency cables.(400 Hz)
I took a class by the phone company long ago called Premise Distribution. Lasted a week. 
Not sure if they are even offering it any more. 

Hope this helps




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IN101 - BICSI Installer 1 Training | BICSI






www.bicsi.org









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StackPath






www.ecmweb.com





Today where everyone is certification happy, would be wise to see what is available in your area.
You might try the VOIP phone sales company


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## MHElectric (Oct 14, 2011)

SWDweller said:


> Part of the answer about separation is answered when you use shielded or non shielded wire.
> I just put 2500 feet of shielded cat 6 in my new home. House is all metal. When I was installing a lot of CAT wire, we found shielded wire was less likely to get get cross talk or interference. The 12"+ rule is an absolute if your any where near medium voltage or high frequency cables.(400 Hz)
> I took a class by the phone company long ago called Premise Distribution. Lasted a week.
> Not sure if they are even offering it any more.
> ...


Thank you for that link. 

We did a lot of phone and cable lines in new construction, but you know how that goes - just because I’ve brushed my teeth a few times doesn’t make me a dentist. I’d like to know what practices the guys who pull and terminate Data & cable day in and day do. 

As electricians, we usually only worry about getting a wire from point A to point B. What do the pros do?


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## AVService (Nov 10, 2017)

MHElectric said:


> Thank you for that link.
> 
> We did a lot of phone and cable lines in new construction, but you know how that goes - just because I’ve brushed my teeth a few times doesn’t make me a dentist. I’d like to know what practices the guys who pull and terminate Data & cable day in and day do.
> 
> As electricians, we usually only worry about getting a wire from point A to point B. What do the pros do?


Speaking for my own jobs I try to wait for you guys to pull your wire so that I can try to stay away from it if possible!

Really


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## MHElectric (Oct 14, 2011)

AVService said:


> Speaking for my own jobs I try to wait for you guys to pull your wire so that I can try to stay away from it if possible!
> 
> Really
> 
> ...


No kidding. What else do i need to know? Punch down points? B pattern on everything? Understanding Patch panels?


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## AVService (Nov 10, 2017)

MHElectric said:


> No kidding. What else do i need to know? Punch down points? B pattern on everything? Understanding Patch panels?


I think you need to hire someone who does this work like you do the work that you know and learn from him.

Honestly there is no “101” course that can be pecked out on the phone in 5 minutes any more than there is for any other skilled trade?

Obviously there is a lot more to doing it correctly than you must think there is.


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## MHElectric (Oct 14, 2011)

AVService said:


> I think you need to hire someone who does this work like you do the work that you know and learn from him.
> 
> Honestly there is no “101” course that can be pecked out on the phone in 5 minutes any more than there is for any other skilled trade?
> 
> ...


No, this is for the company i work at. I’m not under any type of illusion that this can be learned in a 20 minute thread. It takes time to learn this stuff, i know.

Just wanted to update myself on some of the technical points of this work instead of just the “pulling wires” end of it.


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## paulengr (Oct 8, 2017)

Big difference between signals. The SNR for Ethernet is over 30 dB by itself, by design. It also has a deep notch at 60 Hz and 1500 V of isolation so it is effectively immune to interference from common power line interference. So it's back to the standard 2" isolation that NEC gives in Chapter 7 rules. Similar things are also true about CATV and especially satellite LNB signals which are both high bandwidth and higher frequencies so they are inherently already pretty well isolated. This is very different from say USB or baseband video signals like composite video for instance. Also AM radio (FM to a degree), shortwave, CB radios, HAM radios... Those signals are concentrated down near DC up to the Kilohertz or a few Megahertz at best and just about anything can cause interference. That's where shielding is the only really practical answer. And if you read the entire phone company "rules" which trust me, NO phone company data center (NOC) EVER followed religiously, and certainly not in the field wiring, you'd never win a bid. Time to bury that time capsule forever.

Or let's put it another way...have you seen the back of a Cisco 24+ port switch or an IT patch panel? If you have then you know exactly why all these silly rules about isolation are a joke. Think about it...you'd be left using may 2 or 3 ports per switch on the largest switches if you had to space everything 12" apart.

There is a ton of data on this. Allen Bradley used to have several pages of tech notes where they attempted to crash/destroy Ethernet signals by basically doing everything wrong and simply couldn't do it. This was before they were deeply in bed with Cisco. Now they just sell non-industrial Cisco garbage relabled with the meatball. Ethernet is far, far more resilient than many claim. Old practices and rules are from the analog telephone days (0-4 KHz), RS-232 (a few kilohertz), composite video (0-2 MHz), and similar very baseband signals that are just begging to have interference issues with basically everything.

Now YMMV when you attempt to say put say composite video for your surveillance camera across CAT 5 UTP. In that case UTP is very, very resilient to interference by design (twisted pairs) but if you are already borderline in terms of SNR, it can be a problem. So it might work, or it might not.

This is where shielding comes into play. So if you have a shielded cable and it is grounded at ONE END ONLY to the casing of the equipment at that end (generally the source is preferred), any external interference creates a mirror signal on the surface of the shield (mirror charges...basic physics). The two charges are identical but opposites so they 100% cancel out. So the signals inside the cable are completely shielded from outside electrical fields. Now as to the "one end only" rule, this is quite simple. If you ground at both ends, then we form a complete circuit including the ground and the shield. This is called a ground loop. The thing is that this is also called a LOOP ANTENNA. It can be very effective at coupling almost any interference onto the loop where the signal flows around the loop, and that means it can also very easily inductively or capacitively couple the interference directly onto your precious data cable even though it is inside the shield.

So where does this leave us? First we need to identify the type of signal. We need to treat old baseband style signals (analog phone lines, RS-232, +/-10 V signals, millivolt temperature signals) far differently from Ethernet, modulated video signals, current signals (0-20 mA digital or 4-20 mA analog), etc. If it needs protection then if it all possible shielding works 100% of the time. Otherwise all those crazy rules about isolation, crossing at right angles, etc., apply.


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## AVService (Nov 10, 2017)

paulengr said:


> Big difference between signals. The SNR for Ethernet is over 30 dB by itself, by design. It also has a deep notch at 60 Hz and 1500 V of isolation so it is effectively immune to interference from common power line interference. So it's back to the standard 2" isolation that NEC gives in Chapter 7 rules. Similar things are also true about CATV and especially satellite LNB signals which are both high bandwidth and higher frequencies so they are inherently already pretty well isolated. This is very different from say USB or baseband video signals like composite video for instance. Also AM radio (FM to a degree), shortwave, CB radios, HAM radios... Those signals are concentrated down near DC up to the Kilohertz or a few Megahertz at best and just about anything can cause interference. That's where shielding is the only really practical answer. And if you read the entire phone company "rules" which trust me, NO phone company data center (NOC) EVER followed religiously, and certainly not in the field wiring, you'd never win a bid. Time to bury that time capsule forever.
> 
> Or let's put it another way...have you seen the back of a Cisco 24+ port switch or an IT patch panel? If you have then you know exactly why all these silly rules about isolation are a joke. Think about it...you'd be left using may 2 or 3 ports per switch on the largest switches if you had to space everything 12" apart.
> 
> ...


Then add to this that most/many more signals these days will be distributed on twisted pair network cabling and it gets more tricky in real life.
POE power loss and cable gauge snd distance also a huge consideration and cables are not all rated equally despite the labeling.
There is a lot to the design that goes into it all working in the field and its not always practical to implement as specced if even specced fully if at all.


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## Navyguy (Mar 15, 2010)

MHElectric said:


> Could anybody give me a down and dirty structured cabling 101 class? Mostly just the installation practices and what wiring is being used.
> 
> Do we really need to keep 12” separation between low voltage and high voltage? We never did that in new construction.


In my world it is like this...

Everybody wants cat6 / 6a but there are no real consumer equipment that needs Cat6 available yet, Cat5e is still good. If you find something that needs Cat6 / 6a and you want room to grow, put in fibre.

Keep the wiring as straight as possible, keep the twists in the conductors as tight as possible when terminating. If you have to bend, use a large radius for the bend, don't try things like an LB fitting. Always use a grip when pulling cables. Stay away from everything power. Industry bonding and grounding requirements are stupid... unless spec'd and they are paying, use common sense, but never bond to building steel; always back to system ground.

There is no colour standard in the industry, but I find the following is pretty consistent:

Blue = Data Secure
Green = Data Public / WAP
White = VOIP
Red = Security / Camera
Purple = POE Control / Lighting

Velcro is the better option, but tie wraps will work fine, just no sausage rolls! Purchase a cable comb for bundling.

If bundling, try to use a smooth tray vice a "basket" type tray; cross members of the basket crush the cables on the bottom of the bundle.

Residential = A, Commercial = B.

Don't mix and match, if you start with 110, stay with 110. Same for BIX, 66, Krone, etc.

Know the difference between certification, qualification and verification... making a mistake here will cost you a lot of money.

Don't buy cheap networking tools / testers.

Cheers
John


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## MHElectric (Oct 14, 2011)

Navyguy said:


> In my world it is like this...
> 
> Everybody wants cat6 / 6a but there are no real consumer equipment that needs Cat6 available yet, Cat5e is still good. If you find something that needs Cat6 / 6a and you want room to grow, put in fibre.
> 
> ...


Golden! Looks like you were dude i needed to talk to in the first place!


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## MHElectric (Oct 14, 2011)

Is regular Cat 5e or 6 able to be used in outdoor rated locations like RG6 cable is?


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## Southeast Power (Jan 18, 2009)

Tossing cables is idiot work. I have tried many time to penetrate that market and it’s just impossible due to the zero existence of a learning curve.
Anyone with a ladder is a class 2 contractor.
That’s my competition.
The only save is if a permit is needed. In that case, I charge per drop the same as I would for a light or receptacle.


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## AVService (Nov 10, 2017)

There are cables rated for outdoor and burial use just like there are for coax.
All RG6 is not rated for this though any more than standard Romex will be?

Most are flooded but there are some with a powder that are somehow rated water resistant too.

Also I have never seen anyone wire “A” on purpose other than for crossover cables in residential use???


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## splatz (May 23, 2015)

Southeast Power said:


> Tossing cables is idiot work. I have tried many time to penetrate that market and it’s just impossible due to the zero existence of a learning curve.
> Anyone with a ladder is a class 2 contractor.
> That’s my competition.
> The only save is if a permit is needed. In that case, I charge per drop the same as I would for a light or receptacle.


This is true. If you're aimed at the market that really doesn't care much about it, you're getting into a much less profitable business, bad move. 

It would be kind of like branching out into paint and drywall. Unless you have some special competency and you're going to paint museums, billionaire's mansions, and the space shuttle, you're trading down.

There are very profitable datacom jobs, a small percentage, but in most markets they are few and far between. You're not going to be ready to take a swing at them with a crunch course. The customers tend to know what they want, know what to look for, and inspect for their specifications fanatically. You would have a hard time landing work but could wind up taking a worse bath if you do win bids.


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## MHElectric (Oct 14, 2011)

I think most electricians need to have at least a small degree of understand with how to terminate low voltage stuff. Whether they pursue that market or not is another thing.

What prompted me to start this thread was a YouTube video I watched this weekend by a Data/Cable contractor and everything he was talking about was completely different from what I have done in the past. We usually just got a phone/cable line from one point to another and then let someone else terminate the patch panel and punch point. Obviously, there’s a lot more to it than that.


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