Best practice or toolkit for estimating cable run lengths?

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dragonian

Member
Jan 3, 2020
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I'm planning on doing all of the network and LV wiring for a house that I'm building. As it's a substantial amount of wire, and I need to get it all done in a week, I'm trying to plan how much cable to buy. I'm not super afraid of over-buying (it all gets used eventually), but obviously copper prices are up, so don't want to go crazy.

Are there best practices to figure out based on a floor plan? or potentially a toolkit? Surprisingly google hasn't been much help. (maybe this is an industry secret?)
Or do I just need to get out the ruler and start measuring?

Links to floor plan and drop plan for reference (or if you can help).
 

LodeRunner

Active Member
Apr 27, 2019
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Start measuring pretty much, or call an actual LV contractor.

For measuring and estimating, I always start with what the vertical distances are, then add the straight-line distance. Then I tack on up to 25% (longer runs = less, shorter = more, because who wants 75' of slack on a 300' run?) account for the structure and slack needs for termination.

Looks like you have 35 runs planned? Based on a quick add up of the building dimensions, you're probably going to need at least 2x 1000' spools.
 
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seany

New Member
Jul 14, 2021
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(ex LV contractor)

LodeRunner basically said what I would do to get a baseline estimate for initial quoting. Once framing is closer to finished I would do a site survey with either the general, or the electrical contractor to understand routes (especially where you have to cross firebreaks) to understand more detailed routing.

With that said, given how much even "good" cat6a costs (not that much in the grand scheme of things) I will always tell people to buy as many spools as the number of cables in largest drop so you aren't doing full length pulls over again to the same spot. You'll end up with left over cable, but save time and pain.
 

XplodingData

Member
Jan 25, 2020
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Yup. Buy More boxes then the basic math tells you. There's nothing more frustrating than spending hours pulling 2 at a time to a far corner for multiple cameras/APs/Etc, especially if your route includes drops along the way that you could have pulled at the same time.

But that's a time versus money conversation, and a contractor will get the win there since they can bring 8 boxes instead of 2 and get it done in half the time. Then just take the leftovers to the next job.
 

seany

New Member
Jul 14, 2021
12
5
3
Most decent cable will also have distance markers on it as well. Just sharpie mark the box with the last one you saw every time you cut some off. That way you have an idea of what's left. It's typically some arbitrary number based on the spool size at the manufacturing plant. So a 1k box might start at 5925ft and end at 4925ft or vice versa. Just keep a log of it.

When you're done with the whole project sell the leftovers if you don't want to keep some, and the next guy will actually know what he's getting.
 
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