1 Telecom Cabling Ladder racks systems and relay racks Ladder racks systems and relay racks.

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Telecom Cabling

Ladder racks systems and relay racks

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Telecom Cabling

Todays telecom rooms are much more sophisticated than the older IDFs and telecom closet and require a complex system of ladder racks and relay racks to support the network infrastructure.

Putting these ladder rack systems together requires the use of hammer drills, a saws all, wrenches and quite a bit of hard ware.

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Telecom Cabling

Relay racks play an important role in the telecom room and are sometimes referred to as free standing racks.

Telecom rooms can house several relay racks or a dozen racks, which will require some planning on the installers part.

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Telecom Cabling

The most commonly used relay rack is a universal 2 post, 7 foot by 19 inch wide aluminum rack which is capable of supporting 1000 lbs.

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Telecom Cabling

As stated earlier these racks are 19” wide and this width is an industry standard used through out all low voltage systems such as live sound reinforcement, home theater and CCTV.

2 post relay racks come unassembled and will need to be assembled on site.

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Telecom Cabling

The relay rack consists of two base pieces, two top or header pieces (smaller than the base pieces) and two posts.

You will want to hold the two vertical post side by side before assembly to make sure the holes align correctly, you may have to flip one post so that the holes are level between both posts.

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Telecom Cabling

Once the relay racks are assembled they will need to be mounted to the floor using an anchor kit, this is where the hammer drill will be needed because you will need to drill into concrete.

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Telecom Cabling

Once the location of the relays racks have been established you will use the base of the rack as a template to draw the holes on the floor and then drill them out to the required depth (length of the anchor).

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Telecom Cabling

The anchor is dropped into the hole and a set tool is used to expand the anchor and set it, if the anchor is not set properly it will spin in the hole as you try to tighten the base bolts.

DROP IN ANCHOR ANCHOR SET TOOL

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Telecom Cabling

The relay racks will need to be a minimum of 3 feet from any wall, if space is available it is recommended that the racks should be 4 feet from the wall.

This distance allows for any type of equipment and shelves to be installed and still provide room for a technician to easily work behind the relay rack.

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Telecom Cabling

When mounting relay racks space should be provided between relay racks for wire management in some cases you may have vertical wire managers that will have to be attached to the sides of the racks.

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Telecom Cabling

If you’re not provided with vertical wire managers leave 4 inches of space between the racks to manage cables and patch cords running down the sides.

With a 4 inch space between racks you can install wire manager rings.

VERTICAL WIRE MANAGERS THAT ARE 2 “ WIDE AND ARE MOUNTED TO THE SIDES OF THE RELAY RACKS.

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Telecom Cabling

In a telecom room what gets mounted in a relay rack?

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Telecom Cabling

What else is going to be mounted on the relay racks?

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Telecom Cabling

As you can see there is a lot of equipment that will be mounted in the relay racks.

This equipment is specified as “rack mount” which means that it should be no more than 19 inches wide and have hardware that will allow it to be mounted in a free standing rack

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Telecom Cabling

One relay rack will be dedicated to patch panels and wire managers and possibly a fiber optic patch panel (always mounted at the very top of the relay rack with its own wire manager).

The other relay rack is normally dedicated to the network switches, routers, firewalls and wire managers.

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Telecom Cabling

Depending on the size of the space served you may have 2 or more relay racks dedicated to just the cabling.

This means you will need to determine how much rack space you will need for all of the equipment that needs to be mounted in the racks.

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Telecom Cabling

To determine how much room any patch panel, wire manager or network equipment will use up on the relay rack we use the term rack units (RUs).

A rack unit equals 1.75”, in the field we use 2 inches, we rarely mount anything at the very bottom 4 inches of the rack.

So the smallest panel is 1 RU and all rack mount equipment will be specified by the amount of RUs it will use.

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Telecom Cabling

The largest panel allowed is a 5 RU, sometimes the R is dropped and we simply say 1U or 3U.

To the right we see different sized blank panels and how many rack units (RUs) they fill.

A 7’ rack is 84 inches tall so it is possible to fit 21, 2U patch panels and wire managers in the rack. (Using 2” as a unit guide)

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Telecom Cabling

The next thing we’re going to talk about are the ladder racks that are used in the telecom rooms (TRs).

The ladder racks will “T” up to the relay racks and provide a means to manage cable bundles down to the patch panels.

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Telecom Cabling

There are many different pieces to this puzzle, some of the different components will consist of:

Wall supports and triangle supportsJ bolts and splice kitsWaterfalls and corner pieces10’ X 12” sections of ladder rackLag bolts and toggle boltsWire posts and end caps

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Telecom Cabling

They all come together to provide a solution similar to the one pictured below.

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Telecom Cabling

Cables entering and hitting ladder rack in the TR, here we see the wall mount and the triangle support.

Wall mount, toggled into sheet rock.

Triangle support

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Telecom Cabling

The cable will make its way to the relay rack and in some cases a waterfall will be used to route the cables down to the relay rack.

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Telecom Cabling

When mounting ladder rack supports we use lag bolts with fender washers into plywood and toggle bolts with fender washers when mounting into sheet rock.

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Telecom Cabling

When mounting ladder rack to the supports or to the top of relay racks we use J bolts.

When we couple two ladder rack sections we use a ladder rack splice kit..

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Telecom Cabling

When we make a “T” junction on the ladder rack we use an angle splice kit, this “T” will probably go over the relay rack where we would use a top plate.

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Telecom Cabling

Ladder rack systems typically wrap the telecom room, so you will have a cable management system on all four walls.

If not already specified in the TR details we install ladder rack at seven feet high which is the same height of a relay rack.

This allows us to use two or more assembled relay racks as a gauge and a support to install the ladder rack.

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Telecom Cabling

Remember that ladder rack comes in either 10 or 12’ lengths, by supporting it on the relay racks it allows you to mount the supporting hardware along the walls.

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Telecom Cabling

When mounting ladder rack the deep width of the side rail faces down, (it is counter intuitive) and the flat side faces up.

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Telecom Cabling

If there is going to be a very large amount of cable resting on the ladder rack we can add cable management post to keep the cable from overflowing off the sides.

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Telecom Cabling

In most instances we do not use corner pieces of ladder rack, instead we extend a piece to the wall and “T” another piece to it from and adjacent wall.

Factory corners use up a lot of space

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Telecom Cabling

Here are some TR rack designs.