I'm trying to future-proof a soon-to-be constructed police department building, and am reviewing architectural diagrams. Is 1" conduit overkill, and a waste of money?

The architect specified 3/4" conduit for voice/data. I'm worried that upcoming cable standards will make that too tight, and am considering pushing for 1" (at an increased cost of ~$16,000 for the 10,000 feet of conduit).

This building will have at least a 40-year life span - probably a lot longer. I can easily anticipate a time when we'll want two CAT7 cables, or fiber optic cable(s) or who-knows-what in these conduit runs.

The conduits will only be 10'- 12' long. Cables will be on j-hooks and cable tray the rest of the way to the closets.

Conduit is always overkill. Bear in mind that a 1/2" conduit permits nine THHN wires to be pulled in and that is assuming that it is a full run with up to four quarter-bends (360 degrees). Of course, solid copper can endure much higher pulling tension than voice/data cables, or so they say.

10-12 foot runs, which I assume are stubs from outlets into the ceiling area will have minimal impact on the cables. Runs this short can practically be dropped down the conduit with minimal hand pressure. With that being said, I can't imagine why 3/4" wouldn't be more than enough for a typical outlet location.

There are two reasons why I would not worry about sticking with 3/4". Number one is that there is plenty of room for at least six CAT6 cables in it. Number two is that who is even going to be around forty years from now to question your judgment? 3/4" is the industry norm today and you should just stick with what is tried and true for at least the past twenty years.

3/4" is more than enough for any application you might run into. Unless of coarse you are going to run connected amphenols through the conduit or some other large head connector.

Agreed. I might also add that 40 years from now they will probably be using some type of wireless (or brainwaves if there are any brains left after we are gone) and wiring won't be an issue.

-Hal

I agree with everything that's been said about 1" being overkill.

I was also going to mention the wireless is the future aspect, but I can't follow the brainwaves comment... nice one Hal!

There are certain times it would have been nice to have a 1 inch EMT running to some locations, but for the most part 3/4 is fine. I wish they would plan for floor box locations before they put concrete in!!

The reason they don't is that the architechs are smart enough to know that things get changed, moved, etc.

Even the nicest conference rooms get modified at some point, then you end up with a floor box right in a walkway.

There are usually alternatives, and if not, they can get an electrician to do the swearing....not me

Back on topic....I did a job last year where the architech showed 2 x 2" conduits for an island reception desk through the cement floor(1 for electrical & 1 for Tel/Data). Contractor decided to put in 2 x 3/4" conduits to save $$$. I had lots of fun running the data & phone cables through 1 conduit.

However, watch out for "creative" electricians who will daisy-chain two or more boxes, and give you one stub up to the accessible ceiling space!!

The reason they don't is that the architechs are smart enough to know that things get changed, moved, etc... Even the nicest conference rooms get modified at some point, then you end up with a floor box right in a walkway.

That's absolutely correct. I always advise my customers to stay away from floor receptacles and jacks if at all possible. If they are necessary don't try to locate them until they have the furniture finalized. If they don't it's guaranteed they will be in the wrong place.

And, if you are working with a slab-on-grade where you can't core drill it and have access to the space below, they had better be damn certain about the furniture early on before the slab is even poured.

-Hal

I have rewired a police station and a town hall three times in the last 15 years. Luckily, both are wood frame construction, so drilling and snaking has not been a big deal.

If you are talking about poured concrete or block walls, you might want more than 3/4 inch at certain places, but not everywhere.

There are several rules that seem to be universal in this business: (1) They will always need one more wire/jack/port. (2) You can always get one more wire in a pipe, if you struggle. (3) You can always get one more wire through a tie-wrapped bundle.

Rule number one is the norm. They will always ask you to come back to install the printer or the scanner that they forgot, or the extra dedicated line for the fax machine, or the data link between the fingerprint scanner and the state police momma computer. (That one just happened to me, BTW)

Rule (4) You will never be able to get a ladder underneath that ceiling tile you need to get at.

Rule 4A:

The rung you're on is too low. The next rung up is too high.

So lets get back on topic. The poster said nothing about cement. He did however say "The conduits will only be 10'- 12' long. Cables will be on j-hooks and cable tray the rest of the way to the closets."

This leads me to believe that they will only be in the walls with single gang boxes. The max you will fit ever in a single gang box is 6 cables with jacks. Atleast without damage or crimping anyway.

An increase by 16,000 is ill advised and could loose you the bid.