atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Best Backboard Wiring Practices and Standards?

So since I do now know everything and am willing to freely admit it, I figured that I would ask those here with more experience and knowledge then me to share some of it. As always, thanks for your input if you choose to leave some

Intrigued by the post over on the Phone Booth about botched backboard installs, I started to wonder what a proper backboard install should consist of.

Here are some general rules and/or guidelines that I know (or think I know) for back-board set-up. This just comes from seeing how different people have ran them.

-Use a pre-built frame or 5/8 Plywood.
-Spacing between blocks should be even with a consistent distribution/arrangement.
-The blocks should line-up (be level) and not look like polygons.
-Distance between the blocks should be roughly the width of the blocks.
-There should be two Mushrooms above each block (or row) of 66 so that the shaft of them lines up with the edges of the block.
-Rows should be no longer then 4-5 blocks
-The In-House wiring runs under the block and punches in on the right side.
-Cross Connects punch on the left and run up the row to the mushrooms, then across, then back down to the other blocks.
-D-Rings used on cable bundles

I'm sure some (or potentially all, as i'll find out) are wrong.

If you have your own school of thought or just want to correct me feel free. Thanks.

While most installs I've done are where I have existing wiring and the customer just wants to "make do" I clean them up as much as possible. New install I price with backboards, which you install on a sheet of plywood, 5/8 is good painted to room color, or whatever the customer prefers. I don't always use a Green backboard since I've never found a single green and most my installs are small. Old practice called for Red for the KSU, but since most all systems are more PBX in feature than the old 1A2 stuff the backboards were based on I use PBX field of purple. Order on top left to right green, purple, and yellow. below that a row of single or double white distribution rings, depending on the size of the job. Below those the blue station backboards properly labeled by jack location, intermediate terminal location or what every is needed. Makes for a neat job that anyone who knows what the colored backboards means can just walk in and go to the correct location to do their job. No fuss as all is equally spaced from the factory. If I get my way, which I don't always, no new install with out colored backboards.

I really hate unpainted backboard , I did one recently where the GC installed two 4x8 sheets of plywood but refused to paint

I'd already bid the job with the understanding that the backboard would be supplied , customer said don't bother painting

I went ahead and painted anyway ..no up charge

I never use store bought backboard, usually 4x8 3/4 " ply
painted with $5 a gal "oops" paint in a neutral color

layout varies depending on what all gets mounted

sometimes use mushrooms , sometimes 1/2 d ring

I like those premade backboards with the brackets, but most jobs are coming in after someone's mess, with a backboard already on the wall. The job I am doing now has a painted backboard in place, and I just removed all the old blocks and put mine in, properly spaced out. On this job, I am not doing the system, just the cabling. I hope the phone system guy does not make his stuff a mess
As far as punching down house cable on one side, and cross connect on the other, do you mean on the same block, or do you mean the frame as a whole?

Bill: Thanks for the info. I have never used the color codes before. Most of my installs are only 1 or 2 66 Blocks for stations and 1 66 block for CO lines. I can only remember seeing a handful of backboards that were color coded. These were multi-thousand pair installs.

Skip: The way you described it is how I see a lot of backboards installed around here.

Jeff: The way I used it in my original post was on the block itself.

I have a deal, the lumber company cuts my boards to order in 3/4 Aruco it keeps the 3/4" hex head screws from coming out the back like they would in 5/8" material. It's about 9 plys of material and holds screws better than plywood. I usually order a half or full sheet and keep the other cuts as 2x2's or 1x3's or whatever. I try to match the wall or use some whitish color paint, somethimes somebody else's wall color as I get paint by the quart and use a 4" roller to paint the backboards. My local Sherwin-Williams store gets about $11 a job for paint if I mix.

How the board lays out is purely dependent on type of system and where the KSU and patch panel goes. If the KSU ends up behind or underneath the patch panel on the right side of the board, then the house cable tends to end up immediately to the left of the patch panel and the KSU 66 blocks to the left of the 110 block house cable. In that case, the KSU cables terminate on the left side of the 66 blocks and the jumpers come off the right side.

Blocks tend to get mounted 4 high because that's what fits on a 48" board. Yes, I never even thought about it, but I mount my second row of blocks 6" away from the edge of the first one, so plastic parts have 2" without the ears between them. If I have two rows of 66 blocks for a distribution, like a PBX, the left side blocks get terminated on the left and the right side get term'ed on the right so the jumpers fan from the center of the group and out to the house cable.

If I'm using S20-B's, I'll put only a single mushroom at the top and center of the row, about 1" above the top of the block. Most times I'll use a "D" ring to feed the 110 block. With house cables mostly being Cat-5e I try to stick with 110 terminations on the house cable and I still use 66 blocks on the KSU with bridge clips.
If it's a low-budget job or it goes into a patch panel, then I'll break down and eliminate the bridge clips and terminate on both sides of the 66 block.

I never worked for Bell and at GTE we never used colored backboards. I trained in a C.O. and PBX environemnt anyway, so we didn't do those fancy colors, in the C.O. our blocks were all maple and black and we had no backboard, and in the field, we were building the PBX's and sometimes we even got to use them there fancy 66 blocks and a punch tool instead of a wire wrap gun.

Last winter, I did an installation where the cable company telco had to mount a block. I had my first row of 4 blocks and a space to the left for the second row for my PBX. I told the guy to mount on the bottom left exactly level with the 4th block and 6" away. Of course he didn't and I pointed that out to him when I walked back into the room. I left to check on something and when I came back a second time it was still unmoved and he was doing something else. I just reached into my toolcase, grabbed a drill and excused myself and unhooked the block. He said "that's phone company property" and I suggested what he could do with his wannabe phone company. I then proceded to run all my C.O. jumpers and half tapped them with written instructions and left. The guy was unhappy but it got done right.

Of course, if you are not the first guy in, all bets are off. Then, I try to build a board off-site and hang it like a picture.

Carl

The key is to make it look neat. The colored backboard system was great in its day, when systems used 25-pair cables to and from the stations and KSU's, and a whole closet was needed just for a small 1A2 system.

These days, I paint the back board gray if it's in the electrical equipment room, and white if it's in a closet. Since a lot of my work is chasing a previous "expert" I generally rip out what's there, and reterminate as neatly as the cable slack will allow, so the left-side, right-side question is a random one.

I use minimum 3/4 inch plywood, and if the existing backboard is less than that, and I can do it easily, I scab on a second layer. I can only get 1" drywall screws at one lumber yard near me, (not available at Home Depot) and I use them exclusively to mount stuff.

I buy empty fire alarm sheet metal cabinets in 14" by 14", 14" by 18" and 18" by 24" sizes. I get them from an alarm wholesaler. They cost around $25 each, and I can mount a few 66M blocks and/or 12-port data panels (the ones that use the same footprint as a 66M block) inside them. This makes a neat enclosure when the wiring is exposed in an open area such as a basement in a home or small office closet.

Obviously, every run is a homerun, and every connection is a cross-connection. I terminate the 4-pairs on both sides of the 66M50 blocks, and the KSU blocks, also 66M50's, are wired only on one half, with bridging clips feeding the cross-connections.

I always take the incoming CO feeds and make a multiple block, with 4, 5, or 6 appearances of each CO line, using the loop-through punch-down method. This allows a connection, via bridging clips and cross-connections, to the KSU, and ancillary stuff like alarms, fax machines, answering machines, external bells, etc.

When I see a Leviton or equivalent "whole house" wiring cabinet, I rip out the 110 hardware and put in 66 blocks. Try troubleshooting in one of them, looking for a swinging S/C. It's impossible to do without removing every wire, and then when you go to reterminate them, guess what? They're all an inch shorter. Try that a few times, and you's see why I love (to remove) Leviton. They are helping me make my second million $.

I am encouraged by the wealth of knowlege and experience on this forum. Until I found it, I thought I was operating in a vacuum, and despaired to find other like-minded techs who are encountering the same BS that I do every day.

I like this for residential panels;



Looks fancy on the outside, but once it's open its a familiar sight.

Actually, the concern should be to make the installation uniform and consistent. Going into every job with a different-sized piece of plywood, painted in a myriad of colors isn't consistent. I laugh when I encounter plywood backboards that are stained! We are talking about a phone system, not a piece of furniture!

Every system has input and output and output connections that can be terminated upon 66 or 110 blocks, so no block layout is "system specific". If your system only has three tails, then simply leave the fourth space vacant for a future tail. Space really should be left on the backboard in the form of vacant brackets to accommodate every possible tail that the cabinet can have.

Bill, I am with you. I've stopped purchasing green or yellow backboards. I am still sitting on some red ones, but once they are gone, that's it. I have found that blue (station) and purple (PBX) are most appropriate.

Kumba: I never let columns of blocks go beyond four high. Jumpers get to be too "wobbly" and easy for the cleaning people to snag with the vacuum cleaner handle. Using factory backboards really encourages stack multiples of two or four blocks maximum. Odd numbers are never appropriate.

Actually, there should be two mushrooms at the top of each column of 66M1 blocks, aligned about an inch above each side. This prevents the same mushroom from having jumpers coming in from different directions and becoming entangled. Here's an example:



Please note that this is my "lab-or-atory" at home, so it's not as tidy as it should be.

Believe me, the Bell System spent a fortune in designing this modular backboard system and for good reason. Using these, I can mount eight 89B brackets, perfectly-aligned, with four screws in about a minute. Not only that, once I place one backboard that's level and plumb, all subsequent backboards are butted together and end up the same.

Now, at a typical technician's wages, I have to ask the question: Is it cheaper to not use backboards and pay a technician for an hour of time lining up a dozen blocks consistently or to spend an extra $25.00 on the job and have the blocks laid out in 15 minutes, consistently every time? Sounds like a no-brainer to me.

Look, I understand that anyone here who knows me also knows that I am a neatness pr&%k, so perhaps I am going a bit too far. Hey, Jeff knew what he was in for when he posted on this topic!

Your assertion comparing costs for labor vs store-bought parts is absolutely correct. I often cite that argument when advising people to buy data patch cords at $1.00 each versus trying to get all those itty bitty wires into the 8p8c plugs, at $90 per hour.

On large jobs, I compromise, and take a 4-foot carpenter's level and pencil in a series of horizontal lines, every foot or so, and vertical lines, each the width of the level. These become the lines where the type-89 bracket feet will be screwed.

On small jobs, I just measure a few points and start screwing. (In a nice way.)

It drives me crazy to see anything that isn't level and plum, and I don't let my work get that way.