Home Automation in new construction

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codetalker

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Location
spokane
I'm sure many folks will ask why. A few reasons, I have about 30 switches per floor, 6 way switches, 4 ways, 3 ways, I can run them all to the panel room very quickly without even a label on small gauge wire. For lights, it just seems crazy to run 14/3 all over the place to accomplish this task when I can use 14/2&g everywhere. I want to be able to control all the lights, it's tough with a 2 story house keeping track of all the lights. I can cycle them to appear to be home while out. Power savings for sure.

I have a simple plan that I would like to describe and get input especially code concerns from an inspection point of view. I want to control lights with switch inputs. I will leave receptical wiring to standard NEC specs.

Here goes...First thing I want to do is use low voltage (5V) from all the switch boxes (Inputs) using standard boxes and switches but instrument cable, secondly run wire (14/2&G) to every light fixture with a box inline(in the panel room) to insert relays (Outputs).

Before I go further is there someone that knows the code for switched lighting requirements. I'm hoping to use a small computer to read switches and turn ON/OFF lights? Is there some requirement that lights need to be wired the way they are today per the NEC? I know stairways need hard switched lights, that's fine. My inspector is a nice guy but no doubt has to be done to code.

If this seems OK so far I will continue with more details; wire specs and terminations, fuses.

Thanks
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
141113-1343 EST

In my home I have been doing this for 48 years using GE RR relays. All relays are variously located in somewhat localized gang boxes. Up to 12 relays per box. All light circuits are #14. There also some outlets switched with #12 wire. Although I had considered some form of computer control early on there never was a pressing need. I have about 7 gang boxes, but not all are full. Total about 40 to 50 relays.

My control voltage is around 28 V, works well. This is direct control of the relays.

I don't like 5 V as a switching signal, but that bias depends upon how the 5 V is used.

If I was designing a system I might use a two or three wire bus network to the various switches, and each switch would have its own address, and communication on the bus would be by digital signals with error detection. The Dallas 1-wire system is a means to accomplish this function. The Dallas system works well with flat telephone ribbon cable, very fast for termination.

For most purposes I would want a three position toggle switch as the control rather than having to key in a code. The switch should have a protruding lever like any cheap switch. Flat type switches are not easy to use.

.
 

iwire

Moderator
Staff member
Location
Massachusetts
It never ceases to amaze me how many folks want to reinvent the wheel and complicate simple things.:D

I would forget about designing my own system and go with one of the great many lighting control systems already on the market if I wanted to remote control my lighting.

It's probably just me but I have never felt the need to be able to control my pantry closet light from anyplace but right there. :cool:
 
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codetalker

Member
Location
spokane
141113-1343 EST
When you say direct control of the relay; how do you deal with entering a room (light on) and leaving a different door light off?

iwire
I know what you mean. I do electronic design control systems for people all the time, it's my turn.
In my curent house I control the well pumps, lighting, monitor power usage, it can be useful sometimes.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
1411130-1611 EST

codetalker:

The GE RR relay is a mechanically bistable relay with silver contacts, and a set and reset coil set.

Thus, a wired logical "or" set of momentary switches in parallel can set or reset a relay from any one or more locations in any sequential order.

Note, mechanical electrical contacts have very low voltage drop compared to solid-state devices, and thus less power dissipation for a given load current. These are very immune to transient voltage and over current conditions.

This type of control does not require any electronics for simple functions, retains its last state under loss of power, and control is simple combinatorial logic.

.
 

codetalker

Member
Location
spokane
gar:
Good idea on bistable relays.

Cow:
I have looked at relay boards but I think it's best to put the relay in a branch circuit box. Then all that needs code review is the wire out of the box to the relay driver unit. This is where the NEC comes in. Any wire coming out of a box has the potential to have power (120V) on it even if it's a relay drive signal. I'm going to ask a question in the NEC area.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The bistable relay with parallel set/reset contacts also allows for a "master" push button for any number of lights by using a multipole switch or a multipole low voltage relay.
 

masterinbama

Senior Member
As far as I know, the GE RR relays have been around since the 50's because many of the houses built by the engineers that designed and built the Saturn I and Saturn V had them in their houses. I have changed out 5 in my 32 year electrical career.
 

codetalker

Member
Location
spokane
I don't think the relays fit my needs. I'm trying to gather info so I can make decisions on lighting, heating, alarms. one of things you get by reading all the light switches is you know that if a light switch is toggled then a person is at that spot, add a few motion sensors and you can make some decisions. I think i'm off to the NEC forum for some wisdom. Thanks.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
141114-1018 EST

codetalker:

Can you clarify your last post.

What is it that you actually want to learn?

You list yourself as an EE. What were your schools, degrees, and areas of specialization so we can better understand your background?

It seems to me that you have more of a system design problem (logic) than an NEC problem.

Does this statement
I'm trying to gather info so I can make decisions on lighting, heating, alarms.
mean you are building a home for your use, and you are trying to figure out what commericial components exist to accomplish your goals?

.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
I took a lighting class not too long ago and there was some slides on these relay panels and related stuff.
I thought they went the way of the Dinasour years ago. i have not seen one in use in 20 years.
i see how with todays logic controls these can be superior to solid state devices.

Thanks for the thread. i have now updated my box of tools. :thumbsup:
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
141114-1035 EST

masterinbama:

Of the RR failures you encountered what was the cause of failure?

I have had no coil burnouts because of my system design, but I have had several that lost their bi-stable capability, or became temperature sensitive in bi-stable function. My RRs are the type that plugged onto a bus. This plug-on-the-bus may provide mechanical stress that upsets the snap blade function.

Your estimate of 1950s being the origin of RR relays is about correct. I first became aware of them about 1960. Sq-D also made a similar relay and a patent attorney I had association with thought the Sq-D was superior. There were various manufacturers that got into the bussiness at that time. One used a hot wire actuator. The attempt at that time was to try to sell the product on cost saving. There probably was none, and likely higher in cost. The real sales pitch should have been on functional capability.

Also it made no sense to locate the relay at the load vs in a gang box. But this was a selling point. This is because replacement at the load could be very expensive.

.
 

codetalker

Member
Location
spokane
Finished up some of my research, thought I would update the topic I started, automation of "lighting control" in this case. My goals were to simplify (new or old construction) automation using components that I add in or wire in. I'm doing a new construction house with 20 light circuits and would like to keep the hardware price around $15 for each circuit. The hardware will be installed in two places the way I see it, 1) a standard covered switch box or a box with a switch installed to hold a relay, ect. This box should satisfy the NEC as long as all components enclosed are UL and you don't exceed the sq.in max of the box. 2) The other piece is the computer side. Here i'm going to use basic I/O for a description, there are multitudes of cards, driver boards, USB stuff. Maybe we go into that, I don't know.

Original I was planning on using industrial control hardware on the whole house but I decided not to, it's not very fair for the next owner and by making small changes I can get what I want. So i'm going to wire the house using stardard pratice but keep my control purpose in mind.

Controlling the lights seem simple but since there are 2, 3, 4, 5, 6 way light switches, it gets more complex.

Multiple way switches; Any switch in the circuit has to turn the light on or off. This means not only do you need to switch the light but you also need to know the prior state to know the next state.
Wiring a multi-switch light; When I wire my house (new construction) I will run from the panel to the light fixture first, then off to the first switch, this run can be done with 14/2. From that point on 14/3 will be required. I feel this is the best case for saving on wire cost and function.
All multi-switch circuits start and end with a 3 way switch, all the switches in the middle are 4 way. You can find lots of references. I found that if you wire into the first (closest to the light) 3 way switch in the chain then you can determine the state of the light fixture, on or off. Swap out the 3 way for a 4 way and put a relay SPDT after that and there is the automation point. The added relay is now the 3 way switch. I also feel like the relay needs to be a latching type for power savings. Latching relays use zero power after they are set which is important here because the relay could stay in a state for months or years. The next thing to determine; is the light on or off, there are a couple ways, I like this one. Hang an opto-coupler on the line to the fixture and determine voltage or not, switch the optocoupler in or out of the circuit to reduce power consumption. I think another opto-coupler is best here. You only need to apply power when determining light status.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Personally I think you are overthinking this.

With todays wiring , use of Dimmers and other controls, Motion sensors, remote controls I would never wire a home with home run to a light first unless I used a modern home automation panel.

If that is not the case then Power first to the switches or outlet box then a switch leg to the lights. If you run the home run to the lights first then you are stuck with the light where it is because the power goes there first. Then you should think of EMF. EMF becomes greater when all the circuit conductors are not run from line to load and the nuetral travels along with the switch to the load. When you have long switch loop legs(only the hot) , long travlers for three ways you increase EMF.
 

codetalker

Member
Location
spokane
I might have been a little simplified on the home run. I was really trying to stress that the branch should feed the light first and then from there travel to all the circuit switches. This way I don't need to run 14/3 up in the rafters, just the wall switches.

All the current in a multi-way switch system flows thru all the switches and all their neutals when any light is turned on because they are all in series unless I missed something.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
141118-2354 EST

codetalker:

I would describe your approach as a kluge.

I believe you now may be required to run a neutral to each switch box. Also your approach does not eliminate the problem with three and four ways that switch lever direction of operation does not indicate whether someting is being turned on or off. If mid switch position is an open circuit, up is to trigger on, and down is to trigger off, then you don't need feedback on whether a circuit is on or off. You just operate the switch in the direction of the action you want.

Your system does not provide a dimming function from any and all switch positions.

How large are mechanically latched relays with UL listing for 20 A circuits in a residential application? I doubt you can find a small one, other than something like the GE RR relay.

How many of your circuits really need computer control? Possibly a few for crime prevention. Possibly some outside lights with control from your car when you come home at night. Most other functions can be controlled with combinatorial logic. In DC control simple diodes can be used to simultaneously operate many relays from one switch.

In a number of locations motion sensors should be an important consideration. You can use a switch or motion sensor to turn on a circuit, and a lack of motion sensor to turn off that circuit. Possibly multiple motion sensors combined to determine when a circuit or multiple circuits are to be turned off.

I believe your two position switches get in the way of some of these functions.

You should not be thinking low cost if you want a well designed, useful, logical, and flexible system.

.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
I might have been a little simplified on the home run. I was really trying to stress that the branch should feed the light first and then from there travel to all the circuit switches. This way I don't need to run 14/3 up in the rafters, just the wall switches.

All the current in a multi-way switch system flows thru all the switches and all their neutals when any light is turned on because they are all in series unless I missed something.

If you hit the light first with the nuetral , The nuetral current will flow from the nuetral in the light box directly to the branch panel. You will have no nuetral current on the nuetral beyond the light unless you have more lights or load.
This type of circuit can increase EMF.
 

codetalker

Member
Location
spokane
None of the neutrals get connected to any switch until the last switch in the circuit. So in a 5 way switch circuit it goes 3way,4way,4way,4way,3way. The power comes in on 3 way and goes to the light on a 3 way. Neutral only gets connected on the ends so the neutral current flows thru all the switches in the system.
 
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