The jobs we get asked about most, answered the way the advisor answers them: the cable to buy, how much, why, and what it costs today. Adjust any of them to your job.
For a 200 A feeder to a detached building you need two hots, a neutral and a separate equipment grounding conductor pulled through the PVC. Aluminum XHHW-2 is the right call here: it is rated for wet locations and conduit, and at 90 ft the voltage drop is small.
Fourteen doors, each needing a reader, strike power, door contact and REX back to a controller closet on the same floor. The simplest way to do that is one composite access control cable per door: it bundles all four circuits under one jacket so you pull once per door instead of four times.
Riser-rated fire alarm cable in a four-story building means FPLR-listed (or better) power-limited fire alarm cable for both the initiating loops and the notification circuits. The 18/2 is a straight pick: solid bare copper FPLR.
A 200 A mobile home feeder on aluminum runs on 4/0 AWG phase conductors, and it has to be a four-wire cable with an equipment ground because the mobile home panel is fed as a sub-panel. The mobile home feeder cable in 4/0-4/0-2/0-4 is built for exactly this pull: USE-2 rated for direct burial, two 4/0 hots, a 2/0 neutral and a 4 AWG ground.
A buried conduit is a wet location, so the cable through it needs to be outdoor rated and water-blocked even though it's inside pipe. One 1,000 ft reel of Category 6A gel-filled direct burial covers the house-to-garage link, a spare pull alongside it, and the camera run out to the pole.
A return-air plenum ceiling means every cable up there needs a CMP (plenum) jacket, so that rules out riser-rated product from the start. For 40-plus drops you want to still be happy with in ten years, pull Category 6A plenum: it carries 10 Gbps over the full 100 m channel, which your 250 ft longest run stays inside with patch cords.
