sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring raised floor cabling

HI Gang,

I am working on a quote that involves about 185
cat6 (10gig) cabling. The whole facility has
2 x 2 raised floor. Existing cabling will stay in place and become the cabling for the voice side once the data is in.

There are wall jacks in the office areas as well as floor jacks for most of the cube areas.

I have worked in raised floor envirnments, but 99% have been once we're in server room.

So I am looking for suggestions, hints and tips on making thes pulls as easy as possible.

Any traps or major issues I need to look out for?


Thanks


Corwyn

How is the existing cabling run now? Are there cable trays? Follow that.

I would have to check the Code to see what it says about this kind of installation. Data cables under raised floors are not considered the same as in walls and ceilings.

-Hal

Many locales require plenum cable under raised floor.

There's a product called "snake tray" (https://www.snaketray.com) that's not bad for raised floor.

Sam

I looked at a cabling job in an office that had concrete 2x2 raised floor tiles. The wanted a bunch of cabling ran to locations which did not have boxes installed or more importantly no holes in the wall to the space below the floor. I don't know how they expected anyone to drill from under the floor into the bottom of the wall to fish wires up the floor. I told them I could go overhead but they weren't interested and I walked away.

How true. If the raised floor area is a return air plenum, you can still run non-plenum rated cable within it IF the return is for only the air within the sealed computer room. If environmental air is included (not likely), then it must be plenum-rated. Keep in mind that not only is non-plenum cable allowed under raised floors in these restricted environments, but even electrical receptacles and cords are allowed.

Some jurisdictions are tightening up on these standards as much as they can since mainframe computers are pretty much a thing of the past. They still aren't able to enforce things very closely since electrical inspectors really don't know what they are inspecting.

I remember back in my sparkie days, "computer rooms" had to have a panic button that killed all power to the room at each entrance/exit door. As a rookie, I thought it was to kill the computers in the event of a major crash. Nope: It was to kill the air flow in an an effort to minimize the risk of any kind of fire from spreading. Of course, the personnel in the room would be in bad shape if a fire started without a rapid means of shut down.

With real estate costs so high that we don't even get telephone closets allocated, the very idea of a formal "computer room" is quickly becoming a thing of the past.

thanks guys for all the input. Yes the cable is plenum. I know about the snake trays.

They let us walk through but it was totally worthless. they woudn't let all of us into the server room - just a look through the window a-
or lift up the floors. From what you could see in the server room the job was done well and neat - at least where you could see - so I am hoping that it is similar underneath.

But this is why I was hoping for suggestions from you guys about pssible trip ups.


C

they woudn't let all of us into the server room or lift up the floors, just a look through the window.

Red flag right there.

-Hal

Amen to that.

What was that old line about not buying a pig in a poke?

I wouldn't bid on anything I couldn't look at first.

CGs are notorious for overfilling raised floors. We used to get orders to "drop off 30' extra at cabinet X". They felt that this way they could relocate the circuit without us. In short order the underfloor was jammed. I've been paid more then once to strip out an underfloor because it was so crowded it was unusable. Once I was paid to do the SAME location twice in two years. Yup, two years. That's all it took those dingbats to screw up a 25' x 35' room.

Sam

Also, over crowding under the floor causes air flow issues.

The only one I ever did was a mess. Heavily filled with cable and EMT all over the place criss crossing and stacked like spaghetti. We ended up running 1 inch corrugatd innerduct with tape and pulled all our runs at once through those to the relay racks. More expensive, less profit, but the mess was unbelievable and we wanted out of there. I am betting they didn't let you in for a reason.