HV + LV in same gang box...

[drvnbysound]

I thought this was a no-no?
 
Yet, I just removed my doorbell to wire in the Elk-930 doorbell detector... and there it is! 110VAC and Cat5E in the same box. Sure, I understand that the Cat cable is just used for the contact of the switch...
 
If this is possible, why aren't more wired switches available? I bought my house during the construction phase, and I constantly see people here whom are building homes and are inquiring about the various technologies. The vast majority say that hardwired is the way to go and that wireless has issues. So, where are the switches that are conventionally wired (vs centrally located)... with a data connection (a la Ethernet) for control?
 
If it's doable... I suppose the reason for lack of availability is simply lack of demand?

 

[tmbrown97]

shouldn't be 110VAC at the doorbell - should be 16VAC - and the Cat5e is just between the switch and doorbell because for whatever asinine reason, the LV guys use it for EVERYTHING they run nowadays rather than using the correct cabling.
 
Dunno if it's different where you're at, but out here every house I've lived in has had a transformer in a weird place, usually the garage - then basic LV cabling to the actual doorbell unit.

 

[Desert_AIP]

They can be in the same box with a physical barrier, usually a plastic partition inside the box separating them into two separate compartments.

ALC switches come to mind too.

 

[drvnbysound]

shouldn't be 110VAC at the doorbell - should be 16VAC - and the Cat5e is just between the switch and doorbell because for whatever asinine reason, the LV guys use it for EVERYTHING they run nowadays rather than using the correct cabling.
 
Dunno if it's different where you're at, but out here every house I've lived in has had a transformer in a weird place, usually the garage - then basic LV cabling to the actual doorbell unit.

 
110VAC is powering the transformer, which was also in the 2-gang box. House was built in 2007 - not necessarily old.

 

[drvnbysound]

They can be in the same box with a physical barrier, usually a plastic partition inside the box separating them into two separate compartments.

ALC switches come to mind too.

 
There is no physical barrier, as there is no room for a barrier with the transformer in there. What I found most interesting is that both the 110VAC romex as well as the Cat5E cable were both pulled through the same opening in the back of the box as well - no separation at all. Again, I understand that it's not being used as data... but it's still a Category cable.
 
I went a step further and added my Elk-930 in there as well

 

[tmbrown97]

lol! Interesting - never seen them mounted like that out here - it's always just a transformer sitting on its own in a weird spot on a garage wall all by itself.
 
Having Cat5 in the box can be done if properly shielded - even adding some appropriately rated shrink tube over it would satisfy code I believe...
 
Not like I've ever broken this rule (just check my fireplace link in my sig)...

 

[wuench]

It shouldn't be done, but they do it all the time and is allowed.  The principle behind the code is if a wire becomes disconnected and contacts one of the other terminals a fire or electrocution could result.   This is why you shouldn't just "follow code" or rely on the local yahoo building inspector but use some common sense.  Use a sealed transformer or plugin transformer if you can, if not do your best to wrap the terminals so they can't short if one becomes disconnected.   A fuse on the LV side might also not be a bad idea.
 
The doorbell transformer in this house wasn't even in a box, it was hanging onto a lighting box in my basement.  Someone could just reach up and touch the 110V terminals.  A hazard plain and simple, and one of the first things I removed.  I also had a microvoltage wire connected to my gas fireplace in the same box as an HV switch and my single homed furnace circuit junctioned through a smoke detector box nowhere near the furnace.  Only God and the "lec-trishin" who wired this place know what other surprises await. 

 

[drvnbysound]

lol! Interesting - never seen them mounted like that out here - it's always just a transformer sitting on its own in a weird spot on a garage wall all by itself.
 
Having Cat5 in the box can be done if properly shielded - even adding some appropriately rated shrink tube over it would satisfy code I believe...
 
Not like I've ever broken this rule (just check my fireplace link in my sig)...

 
No shielding on the Cat5; standard indoor rated cable. The same wiring that they used for my phone lines. No shrink tubing either. It was wired like any other wiring that I've seen an electrician do; the outer sheath was cut back to the back of the box leaving the twisted pairs exposed in the box... Obviously only needing a single pair to be used for the door bell switch, but all the other conductors were there at the same length.
 

It shouldn't be done, but they do it all the time and is allowed.  The principle behind the code is if a wire becomes disconnected and contacts one of the other terminals a fire or electrocution could result.   This is why you shouldn't just "follow code" or rely on the local yahoo building inspector but use some common sense.  Use a sealed transformer or plugin transformer if you can, if not do your best to wrap the terminals so they can't short if one becomes disconnected.   A fuse on the LV side might also not be a bad idea.
 
The doorbell transformer in this house wasn't even in a box, it was hanging onto a lighting box in my basement.  Someone could just reach up and touch the 110V terminals.  A hazard plain and simple, and one of the first things I removed.  I also had a microvoltage wire connected to my gas fireplace in the same box as an HV switch and my single homed furnace circuit junctioned through a smoke detector box nowhere near the furnace.  Only God and the "lec-trishin" who wired this place know what other surprises await. 

 
This is the first time I've ever done anything with a doorbell, I don't know how past doorbell transformers were manufactured. Maybe that has something to do with it... my transformer was sealed; the back had a pigtail for the 110VAC wires, the front had 2 small lugs for the 16V wiring.