Touchscreen Question

[broconne]

Ok - Accepted an offer on my current house, so time to start the planning in depth for the new house.

I have read the wiring your new house 101 a few times, starting to get a handle on everything.

The question I have is about power for touchscreens, the 101 doc says:

"Don't forget to run power for the touch screen and PC if needed."

What sort of power are we talking about here? For maximum flexibility do I need to have an outlet in the actual wall cavity? I am hoping touchscreens I buy will have PoE - but not sure. Do most touchscreens expect A/C outlets?

 

[sic0048]

I would plan for any contingency you can think of.

For touchscreens this means wiring for three potential power requirements:
1) Full 110v HV line
2) 12v power from a transformer located elsewhere. This would require LV wiring from the "other location" to the touchscreen location.
3) POE - no special wiring needed since you'll obviously be running network cables to the location.

Honestly I think touchscreens with POE are few and far between. The most likely outcome is #1, then #2, and finally #3 IMHO.

The other question to think about is where are you going to locate the computer to run the touchscreen? Is it going to be an AIO built into the screen? Are you going to have a low power device located at the screen? Or perhaps you'll located the computer at a remote location and extend the required connections to the touchscreen.

You need to plan for all three options again. This really simply means having 110v power (which you should already be planning for) and several cat5e wires that could be used to extend the signals from a remote location. This is actually what I do personally. My computer is located in a central closet and it drives a touchscreen in my kitchen. I need 110v at the screen for power, and I use 2 cat5e wires to extend VGA, Serial, Sound, and USB connections from the computer to the screen. I use a USB extender for the USB and a Cybex Longview KVM extender for everything else.

 

[broconne]

I would plan for any contingency you can think of.

For touchscreens this means wiring for three potential power requirements:
1) Full 110v HV line
2) 12v power from a transformer located elsewhere. This would require LV wiring from the "other location" to the touchscreen location.
3) POE - no special wiring needed since you'll obviously be running network cables to the location.

Honestly I think touchscreens with POE are few and far between. The most likely outcome is #1, then #2, and finally #3 IMHO.

What sort of wiring do I need for 12v power? 18/2?

Is it code to have a full 110v outlet inside a wall? I guess they would just mount it to the stud and face it towards the cavity. #1 seems like an issue from a heat perspective.

 

[ano]

Is it code to have a full 110v outlet inside a wall? I guess they would just mount it to the stud and face it towards the cavity. #1 seems like an issue from a heat perspective.

In a word, no. It needs to be mounted to a stud, it needs to be in a box, and it needs to be easily accessible. The last one is the tricky one. You may want to mount the outlet in the attic, then run 12V down to the screen.

 

[broconne]

Is it code to have a full 110v outlet inside a wall? I guess they would just mount it to the stud and face it towards the cavity. #1 seems like an issue from a heat perspective.

In a word, no. It needs to be mounted to a stud, it needs to be in a box, and it needs to be easily accessible. The last one is the tricky one. You may want to mount the outlet in the attic, then run 12V down to the screen.

The accessible requirement is the hard one. I am concerned about the outlet in the attic - part of my attic will have flooring on it. So, if you legally can't put 110V in a wall - seems to be a hard one to pre-wire for. What is the downside of 12v DC wired to a central location? Also does one just use 18/2 for that?

 

[jlehnert]

Don't talk yourself into a problem here. The outlet cannot be SEALED inside the wall. However, it can be placed inside a wall cavity if the cavity is accessible.

If the touchscreen is installed so it can easily removed for maintenance, then you should be okay (but check to be safe). Even if the receptacle is installed behind the touchscreen, it still needs to be fully enclosed in an electrical box, and covered by a wall plate.

If you install the touchscreen so it takes 10 minutes and a circular saw to remove it, then I doubt the inspector will okay it.

The question basically boils down to what your local inspector considers "accessible".

 

[broconne]

Don't talk yourself into a problem here. The outlet cannot be SEALED inside the wall. However, it can be placed inside a wall cavity if the cavity is accessible.

If the touchscreen is installed so it can easily removed for maintenance, then you should be okay (but check to be safe). Even if the receptacle is installed behind the touchscreen, it still needs to be fully enclosed in an electrical box, and covered by a wall plate.

If you install the touchscreen so it takes 10 minutes and a circular saw to remove it, then I doubt the inspector will okay it.

The question basically boils down to what your local inspector considers "accessible".

Thanks for the tips. There wont be a touchscreen in place during inspection - just trying to prewire here. So not sure how I could make it accessible enough to pass inspection - without a nice hole in the drywall

 

[sic0048]

You could always mount a box and wire it normally and just put a flush face on it. It won't look as good as untouched drywall, but when the plate is painted the wall color, it shouldn't be that bad IMHO either.

Also, the wiring inspection would be done before the drywall goes up.

 

[dougmeredith]

Thanks for the tips. There wont be a touchscreen in place during inspection - just trying to prewire here. So not sure how I could make it accessible enough to pass inspection - without a nice hole in the drywall

Then you don't have a problem, as the inspector won't know it's there. It's your house; use your own judgment (unless you have poor judgment, then ask someone else) and make sure you don't do anything dangerous.

Doug

 

[Neurorad]

Why does the NEC require easy access to the outlet?

If it's unsafe, I don't want to do it.

If it's for convenience, then it wouldn't matter, in my opinion.

I'm betting it's in the NEC because it's a potential fire hazard, for some reason.

Could a touchscreen be mounted over a recessed outlet box?

When will a wireless power system be developed? A giant magnetic field could be generated, covering a kitchen, which would then induce current in a conductor in the wall...OK, not serious.

 

[jlehnert]

Why does the NEC require easy access to the outlet?

In this case, I think it's actually common sense. You cannot have any joints/splices/connections that you cannot get to for repairs. An outlet sealed inside the wall would qualify as one of the above. Also, if a fire were to start in a box buried in the wall, it would be able to get a good start before it would trigger smoke detectors in the house.

The "accessible" part comes from the inspector’s interpretation of the code. If it becomes too difficult to access, then the inspector decides that it is "sealed" and gives the thumbs down. As mentioned multiple times in this website, the code/law is not what is written in the books, but how it is interpreted by the inspector. It's sort of silly. How easy is it to get to the electrical plug behind the washing machine, let alone one of the big Sub-Zero refrigerators. Heck, it takes two people to even roll those monsters.

Could a touchscreen be mounted over a recessed outlet box?

Yes. They even make special boxes now that have recessed jacks to go behind flat screens. I believe I've seen them from Carlon.

 

[commexperts]

Here is what I did and why.... I used a ELO 1537L touchscreen it is made for a DIY kiosk, it is very low depth and has several mounting options. I had it framed in a deep frame made for a canvas painting which came out very nicely (it fits in the frame and sticks out the back less than 3/8 of an inch). I painted black two 1/4 inch depth strips of wood trim and mounted them on the back of the frame on the Left and Right side (mounted vertically the full height of the frame) to hide the small space off the wall and any wires behind the frame. I ran two CAT5 cables (one shielded) and one 16/2 awg for power... the two CAT5 run to my computer (a file server I have in a rack in my master closet near all of my structured wiring) one (the shielded one) for VGA via a Mux Labs Balun and the other for serial via a DB9 to RJ45 hood on each end, both ends of both cables are terminated into CAT5 keystone inserts (one shielded)... the 16/2 awg wire terminates on each end into a keystone 1/8" phono jack insert (made by ICC) and I made custom short little adapters for each end to take it to the 2.1 mm barrel connector that is used for the ELO touchscreen... the power adaptor side of the cable goes to a near closet with the insert and faceplate next to an 110v outlet that is controled (Insteon) by my Elk M1G. The Elk M1G turns the outlet off when we set the alarm (away, night or vacation) and on during the day when the alarm is not active. The Balun was a little too big to fit in the extra space at the bottom of the ELO touchscreen and between the wall but I took the case off of it and soldered it right on to the back of the ELO touchscreen (shield around the RJ45 to the shield of the touchscreen with the pc board outwards) this made it just fit in the space. The frame was fitted with three keyhole hooks and the wall has three screws (two at the top on each side and one on the bottom center) measured to the right spot and depth to hold the frame solid and flat against the wall. The faceplate for the two CAT5 and one 1/8" phono inserts is mounted near the bottom of the frame to fit into the 3/8" gap off the wall and the 1 " gap off the wall at the bottom of the ELO touchscreen. Everything behind the frame is covered up and not visible when the frame is mounted. I am running ELK RM on the PC and a screen saver (after 1 min.) that shows the pictures my wife puts into a special shared folder on the fileserver but a simple touch will bring the ELK RM back... The server is a super small rack mount Mini ITX box with a Intel Core 2 Duo Mobile Processor, 2 GB Ram, and 2 750 GB drives mirrored (RAID 1) drives from Logic Supply (this thing is no bigger that a 1U rack mount switch). The server is mostly used for storing our media (pictures, music, recorded TV shows, etc..) and important files, but now is also running the ELK RM. I have the PC setup to autologon and run ELK RM upon bootup and also have the Microsoft on-screen keyboard running incase I need to run anything else from the touchscreen. This all in all has been a great solution and I did not have to do any major rough in or damage to my wall other than one single gang faceplate and three screws (#8, 2" hollow wall anchor bolts). If I move I can just take it with me like any other picture frame hanging on the wall. I will attach some pictures......


Todd Tarkington
Communication Experts Group
(972) 444-8202

 

[TLCNORM]

Todd,

That looks awesome. Puts mine to shame. Any pictures of it off the wall so we can see the back of the frame and the wall?

 

[broconne]

Todd -
That is really really impressive work.

I have another touchscreen question. In places of entry - front door, garage, back door, etc. Do people keep both a keypad and add a touchscreen or do they replace the keypad with the touchscreen?

I am not sure if I will run Elk RM or perhaps CQC with a custom interface. I am a little apprehensive about using a touchscreen to disarm the alarm - in terms of if the CQC server goes down for some reason, etc.

Thinking about it, I probably don't want to put touchscreens at areas of entry. Here is the list of areas where I want to prewire for an keypad and/or touchscreen.

Keypad Only:
Front Entry
Garage
Ready Entry

Keypad/Touchscreen (Wire for keypad - add touchscreens later as finances/advances allow):
Living Room Wall
Kitchen (Not sure where to put this in my floorplan)
Second floor hallway (touchscreen only?)
Both sides of where the bed would be placed (his and hers)

Any obvious places I am missing here for a pre-run for keypads/touchscreens?
I left off the basement because that is unfinished so I can run those myself.

 

[Steve]

I think in places where you would have a regular keypad, a 7" touchscreen would not be bad, but the larger screen like 15" are probably most used in halls or kitchens that are more trafficked. I would not worry about a TS to disarm security as a CQC outage would be very rare and also, if I did have all TS's, I would still have a basic system keypad somewhere, even if mounted by panel. That one could always be used in the rare event of some glitch or outage.