commercial office cat 5 running calculations

[wiredup]

hi guys, i was wondering what is the best way or perhaps you guys can share how you would calculate how much aproximate cat 5 wire you would use for a two story 20000 sq ft commercial office. most rooms have one telephone data jack. ?? and this would be plenum rated wire. please help.

 

[barbeer]

 

[brantmacga]

barbeer has the best answer i think, unless you do this type of work all the time and know how to estimate it based on previous experience. don't forget up and down walls.

 

[480sparky]

And don't measure 'as the crow flies.' You'll always run into ductwork, piping systems, structural elements, etc., so you'll need to avoid those spots.
As brantmacga says, don't forget to account for the vertical portions. Check the plans for the ceiling heights. Not every office is 8'-0".

 

[iwire]

Along with the other good suggestions take a look at the specs and see if a 'service loop' is required at each location.

 

[brantmacga]

'service loop'

that would be a good practice to follow anyway.

 

[LarryFine]

Okay, I give; what's a 'service loop'?

 

[480sparky]

A couple loops of cable gathered at the top of the conduit running down the wall to the end user. It's there to allow moving the outlet (further away) to another location in the future without having to pull another run and reterminate it.

At least, that's my guess because I've seen it done that way.

 

[wireman71]

You need to get the specs on exactly what and how many Cat 5 runs you'll be doing. I've seen absurd amounts of Cat 5 pulled to just a cubicle. What if in each room they want 4 Cat 5 instead of the two you're thinking of? Tell them T & M if they can't give you specs.

 

[Memnon]

Another thing to consider is where you will reach the second floor from the first floor. Your cable lengths may depend heavily on where your riser location may be.

 

[mkoloj]

I have seen accurate estimations given by taking the average of the length of the longest and shortest runs, adding 10% of the average to that and then multiplying the average by the # of cables to be pulled.

IMHO The scale master is great for smaller jobs.

Barbeer,
Are you using it to measure all the runs on larger jobs with high #'s of comm cables?
If you do or have in the past, how close have your estimates been?

 

[barbeer]

Although I have never personally bid a comm wire job using this tool, I believe that it would be as accurate as the user wanted it to be if used along with some of the good advice in previous posts.