The electrician was installing the cat3 phone wires in the same holes as the A/C wires. It was guaranteed to induce a hum.
The correct approach is to keep the low voltage wires as far from the A/C as you can, and if they cross, keep the crossing at 90 degrees. Don't run them in parallel unless they are separated by feet (plural). If you have to, you can run them in grounded metal conduit as a shield.
I probably went overboard on this, but doing it inadequately meant 60 cycle humming on the phone lines and an utterly ghastly bill to rip the walls up and fix it.
He also was installing cat3 (POTS cable) and R59 cable (1970's cable TV stuff). I pulled that all out and threw it in the trash, putting in cat5 (cat5e and cat6 are better, but weren't available then) and quad-shielded RG6 cable.
Getting the best cable available cost maybe 20 or 30 dollars more, so it's crazy not to do it. The network and cable speeds have all increased dramatically since I installed it, and the cables have all worked like a champ.
Even the cat5 cables are happily carrying gigabit Ethernet.
I have a couple plugboards in the basement where all the wires terminate.
I did the whole thing for less than a grand. If an electrician had done it, it likely would have been 10 or 20x more.
If an electrician had done it, it likely would have been 10 or 20x more.
Hmm, that is like twice the amount one would typcially pay here. Still, don't froget the working hours you put in there :) plus the fact that usually technicians get their materials for cheaper than you do (also because in my case it's only 6% VAT instead of 21%). I did many such calculations when renovating and for some things it was actually cheaper to get a technician.
This usually works without any issues, but on one type of projector they had used a non-shielded network cable internally in the projector and if the projector lamp was lit juuuust at the right moment, the handshake would fail and the film would not play. Normally it wouldn't be a huge deal as the handshake happens just before the film and the lamp is usually lit on the beginning of the show long before the film starts. HOWEVER, there was this one cinema chain that had standardized their playlists in such a way that they for some stupid reason turned of the projector lamp in between the trailers and the film (I think to "introduce" the film) and then turned it on again just before the film with the result that the handshake failed 3 out of 10 times or so.
Long term solution was to replace the shoddy cable. Short term solution was to change all their playlist templates to blind the lamp instead of turning it off. Like they should have done to begin with.
Sure, they buy materials wholesale, but they bill you full retail for it. I installed around a mile of wiring :-)
But I also got it exactly the way I wanted, the wires run where I wanted, and I bought professional quality tools to do the work, and still have/use them. I like working with my hands now and then, it's viscerally satisfying in a way a keyboard never is.
The typical electrician gets it indeed for cheaper than market rate, then charges it to you retail rate plus 20% to account for the "trouble" of sourcing and purchasing it.
I never claimed that.
The typical electrician
Maybe you rather mean 'the typical electrician I met' or so because I know for a fact the rest of that sentence does not apply to the ones I met myself.
I know that twisted pair is supposed to be resistant to that, but I wasn't going to risk it and didn't have a good way to test it. I didn't want even a teensy bit of hum, and there isn't any :-)
Many houses have concrete walls, floors and ceilings, so you don't run extra tubes easily...
Reconfiguring switches is next to impossible and via existing switch wires you can dim/switch the lights but not change colour(temperature).
So here the original switches are removed and the connection is bridged (always on) and battery/kinectic powered ZigBee switches control the lights directly, even if the gateway is down.
Presumably that is not because of interference concerns but because of the danger of mixing high voltage and low voltage circuits in the same conduit, right?
As others have noted, conduit isn't usually used in houses in the west.
Source: US National Electrical Code
This means problems like fires spreading to adjacent buildings and fires trapping people where they can't escape are much reduced; you'd never see a repeat of the great fire of London in an American suburb because there's practically a fire break between every single home.
This is made affordable by America's vast tracts of land and high rates of car ownership.
https://en.wikipedia.org/wiki/Great_Chicago_Fire
The same day, a forest fire ravaged a number of small towns:
I had a house with mostly Armored Cable and came to appreciate it. Especially after I opened up a floor and found an exposed conductor on some Non-Metallic that had been chewed by a squirrel.
There are still existing functional knob and tube wiring systems that are 100 years old
I've gradually added GFCI outlets to each circuit. They're not grounded, unfortunately, but they do trip if something were to go wrong. And it allows us to plug in 3-prong plugs without using those horrible 2-to-3 adapters.
We had to change home insurance companies because Amica blacklisted us the instant they heard there was knob-and-tube wiring. A few other companies have the same approach. But it's not like homes are spontaneously combusting everywhere because of it.
Guess where I am ;-)
(Not in Chicago/Cook, though.)
Isn't twisting the pairs supposed to prevent that? Isn't that what makes it feasible to run telephone lines on the same poles as electricity, thus allowing the POTS system to be practical?
POTS is legacy now, so I'm not sure how much of a consideration it is for modern builds.
There are safety issues with running network and power cables close to each other, but generally on small domestic systems crosstalk between data and power shouldn't be a serious problem.
The exception is if you have a lot of hash on the power lines from USB chargers, unfiltered noisy motors, or white goods that generate both digital and analog noise.
Ferrites or other kinds of filtering can help. So can using shielded cat cable.
While the level of knowledge among electricians regarding network wiring is gradually increasing, the conventional wisdom for anyone who wants network wiring installed professionally is to hire a contractor that specializes in low voltage wiring.
Still I agree it isn’t worth the headache of issues to save $20 and it’s more futureproof to use better cables.
They also said that stp is a lot harder and expensive to install.
If it's truly done there's no reason for change. However getting there, to what for us is the most optimal configuration, is what was the main incentive for me. The way it is now it requires almost no ahead planning. I.e. for most rooms we had no idea on beforehand how we were going to pupulate them with furniture and which activity we'd do where, so I just went 'cable for lighting in the center, at the side on each wall, and some extra' and then put the switches in sensible places i.e. usually next to room entrance. Then during the next years hook up as needed and adapt if needed. E.g. couple of months ago we needed an extra desk for working form home and one extra for my GF's new hobby, so we just put some desks to a wall and instantly can get a light above it. With a fixed configuration you'd either need to think of that in advance, or use the light centrally in the room which makes you sit in your own shadow. or add lights you just plug in the wall socket but that's extra cable, and especially for desks it's hard to find a suitable one. Also throughout the years I've made small changes here and there to change things like being able to turn on the light in the bathroom from the bedroom, or turn on light in the kitchen from the place where we eat so you don't have to look for th kitchen switch in the dark. Sure those are just nice-to-haves but pretty convenient. I've been and lived in quite a lot of houses where the whole configuration was pretty akward. Though I get some people don't care about that.
I think by now I've got rid of all the R59 cable sockets and POTS stuff too except for one POTS socket in the cabinet that holds the fuse box. If anyone ever wants to reintroduce a wired telephone they can just reuse a CAT6 cable, but I doubt this will happen.
These days, of course, I don't use the POTS much.
Can you explain what the problem is? I also run cat5 (or maybe even cat6, don't remember) to every room, most even multiple times, just put it in walls/cailings/whatever worked and all 40 or so sockets work just fine.
I turn the switch on, the lights go on, I turn it off, the lights go off.
I run a star configuration for switches and light points, where all switches are on 12V DC and use a 'patchboard' to hook them to impulse relays which drive the lights. Still switch on/light on, but you can select which switch does what, easily hook up miltiple switches to multiple light points etc. Not domotica, but still much more dynamic than traditional build-once-change-never.