Cat 5 for phone and doorbell?

[mrVanagon]

Greetings all,
I want to add a phone extension and a doorbell (button by the front door, chime in the garage) to my garage. Can I use a single direct-burial cat 5 cable to provide telephone and doorbell for my garage about 75' across the backyard or am I likely to get interference between the two?

 

[Infinia]

Greetings all,
I want to add a phone extension and a doorbell (button by the front door, chime in the garage) to my garage. Can I use a single direct-burial cat 5 cable to provide telephone and doorbell for my garage about 75' across the backyard or am I likely to get interference between the two?

hi
Yes that is fine, the twisted pairs are designed to minimize what you fear.

 

[Furd50]

I would suggest doubling up on pairs for the door bell. the phone should be fine.

 

[ddawg16]

Door bell will be just fine with a single pair of wires.

 

[dogdog]

you might want to use something that is 18 gauge or more for doorbell..... cat 5 at most is only 22gauge. Might not have enought oomph to run a door bell at that distance.... mine have a hard time doing that.....

 

[justsam]

First I am going to assume this is conventional analog phone extension.
The phone will not interfere with the door bell but the door bell potential,about 18vac is not something I would want in adjacent phone pair.
Signals of near equal amplitude will play nice but that is not the case here. Balanced twisted pair can only attenuate so much.

If you can at all run a different cable you will be better off even if your phone is not analog but VOIP.

 

[ddawg16]

Personally, I prefer wireless door bells. You do away with the transformer.

And you're not limited to where you put the 'ding dong'.

 

[CharlieM]

You can run Cat 5 plus LAN cable, or sometimes its called Cat5e + 18/2 Siamese CCTV over IP cable. Or just run both in the ditch Some CAT5 or regular JKT, with 18ga power for the bell.

 

[M_George]

If the doorbell is 24VAC you will likely get a 60 cycle hum on the phone.

 

[ddawg16]

If the doorbell is 24VAC you will likely get a 60 cycle hum on the phone.

Good point....

But if the OP uses good Cat5 or 5E....the twist in the wires should reduce it.

Even so, the 60Hz is only going to be induced when someone presses the button.

Another reason to go wireless.

Better yet, put in a door knocker...needs no power

We don't have a door bell.....if it's someone we know, we know they are coming over....and they have our phone number. If it's a sales person, I don't want to talk to them anyway.

 

[dave*99]

Good point....

But if the OP uses good Cat5 or 5E....the twist in the wires should reduce it.

Even so, the 60Hz is only going to be induced when someone presses the button.

Another reason to go wireless.

Better yet, put in a door knocker...needs no power

We don't have a door bell.....if it's someone we know, we know they are coming over....and they have our phone number. If it's a sales person, I don't want to talk to them anyway.

He is going to need one hell of a door knocker to hear it 75' away in his garage.

 

[Bert_]

Personally, I prefer wireless door bells. You do away with the transformer.

And you're not limited to where you put the 'ding dong'.

I am on the oposite side of that. I hate wireless doorbells, they aren't built to last very long and you have to deal with batteries. A decent wired doorbell will last for years and years.

I'm surprised no one has mentioned running conduit. Especially on this forum were everyone seems to think that direct bury is the devil. I will suggest a conduit since, unlike running line voltage to a shed, communication technology changes all the time. Now albeit a phone line isn't likely to change at all anytime in the future, a 3/4 or 1" pvc would be a good option. either that or maybe run some #14 UF for the doorbell. I don't think I would be concerned a about a doorbell and phone in the same conduit, that's why the pairs are twisted it shields the wires from noise. I would run something larger than #22 for the doorbell. Maybe a #18 or even some #14.

 

[ddawg16]

Here is what Bill Cosby has to say about door bells.....

 

[wyliesdiesels]

I wouldnt use CAT5e (24awg) or CAT6(23awg) for a doorbell over that distance. Voltage drop may be too high...

 

[mrVanagon]

Thanks for the replies guys. The house already has a chime on the ground floor and one in the basement with buttons wired for the front and side door. Wireless has a place but I'll stick with what's here already.

The cable I plan to use is a direct burial CAT5e I bought for almost nothing during a clearance sale at Lowe's, where I work. I think there's about 400' on the roll and I paid less than $.03/ft as I recall so I'll likely run a total of 3 cable in the ditch: 1 for data, one for doorbell (with the wires twisted together to form a single pair) and one for phone.

Thanks for the input. This part of the project has been pushed back by circumstance more than a few times. I'll let you know how it goes when this is all done.

 

[ard]

I'd toss in a run of 3/4" PVC conduit- what, $20?. The pull whatever you need through it.

 

[ddawg16]

Wire the door bell wire to a relay.....the current draw will be in the ma range....and you can run what ever you want off that relay....and use 120Vac...

Maybe have a buzzer and a light?

While you are at it.....add a wired intercom?

 

[mbutler]

Let's look at some numbers, purely hypothetical, of course. Let's say we've got a 16VAC 30VA
transformer driving our doorbell. Let's also say the chime is taking the full capacity of the transformer,
which would be 1.875 A at 16VAC. Now, cat 5 with 24AWG conductors has a resistance, per
conductor, of 25.67 ohms/1000 feet. So, our doorbell loop is 75 * 2, or 150 feet, giving a loop resistance
of 3.85 ohms.

At 1.875A, the drop for one conductor pair is 7.2 VAC, about half the total supply voltage.
Adding conductor pairs, you get a drop of 3.6 VAC for two in parallel, 2.4 VAC for three in parallel
and 1.8 for all four conductor pairs in parallel.

Looks like a good way to set the chime volume to me. Also, I doubt that the chime takes the full
output of the transformer; those types of transformers tend to get rather warm at full output and
don't last long.

I especially enjoyed the 14AWG suggestion! The drop for that one is essentially a tenth of the
24AWG in the cat 5 cable.

Mark

 

[dave*99]

I have a standard solenoid type chime doorbell in my house. I added a remote (wired) piezoelectric sounder in my shop. It's loud enough to hear over the running table saw. It draws very little current.

There are low power options for the remote sounder. Current draw would be minimal and the voltage drop would also be minimal.

 

[nsula_country]

I like the idea of running multiple runs of Cat5. One for phone, one for data, and parallel the solids for one pole of door bell and all the stripes for the other pole.

T-stat cable would be better, but you already have the Cat5.

Good luck,

CT