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-   -   Any issue with long run between relay and lights? (http://www.diychatroom.com/f18/any-issue-long-run-between-relay-lights-158799/)

gstein67 10-03-2012 06:39 AM

Any issue with long run between relay and lights?
 
Hi all,

I'm developing a home automation lighting system, and would like to learn if there are safety/other issues with long runs between the controlled-relay and the powered devices.

For maintenance purposes, I'd like to move all the low-voltage/control circuits to one maintenance closet. So let's say that I have a switch at 100' sending a signal back to the automation system. That triggers a relay (in the closet) to activate lighting in that 100' location.

Are there any specific concerns with this setup? Grounding, voltage drop, whatever?

(beyond low/high power isolation, breakers, and wire gauge; these three, I think I can handle)

And from a cost standpoint: for lighting power, is it significantly cheaper to have local junction boxes instead of long home runs for the power? Should I run appropriate power on *one* circuit to the distant area, and then break out the (say) 3 relay-switched lighting runs? (rather than 3 long-run power circuits)

Thanks!
-g

rjniles 10-03-2012 07:09 AM

Any answer you get will be that persons opinion, so I will give you mine:

Current home automation systems (certainly in retrofit applications) tend to be wireless. Insteon is a brand and there are others. The beauty of these systems is they do not require rewiring of the existing house. They also can be easily removed if you decide to move. They are decentralized in that you place the modules or switches at the location you need them.

http://insteonreviews.com/

gstein67 10-03-2012 07:24 AM

Quote:

Originally Posted by rjniles (Post 1022681)
Any answer you get will be that persons opinion, so I will give you mine:

Current home automation systems (certainly in retrofit applications) tend to be wireless. Insteon is a brand and there are others. The beauty of these systems is they do not require rewiring of the existing house. They also can be easily removed if you decide to move. They are decentralized in that you place the modules or switches at the location you need them.

http://insteonreviews.com/

Thanks for your thoughts.

I'm working on new construction, and DIY to lower costs. I can locate the relays near their target light circuits, but for maintenance purposes I'm curious if relocating them to a central/maintainable closet, and creating long runs poses issues.

Cheers,
-g

rjniles 10-03-2012 07:32 AM

Quote:

Originally Posted by gstein67 (Post 1022683)
Thanks for your thoughts.

I'm working on new construction, and DIY to lower costs. I can locate the relays near their target light circuits, but for maintenance purposes I'm curious if relocating them to a central/maintainable closet, and creating long runs poses issues.

Cheers,
-g

I would be leery of installing a proprietary (or even a DIY) home automation control system that is hard wired. Think down the road what will happen if you can no longer get parts for the system. Or if you decide to sell the house, the buyer may worry about how he will keep the system functional.

JMO

kbsparky 10-03-2012 08:23 AM

I'd rather have a hard-wired system than a wireless one any day.

As for parts, the wireless system would go obsolete much quicker than a hard-wired one. No batteries required on a hard-wired system, either.

For example: The GE RemoteRelay system was popular 50 years ago, and you can still obtain replacement parts today.

Billy_Bob 10-03-2012 09:06 AM

I too prefer hardwired systems to wireless. Hardwired systems always work whereas wireless can be subject to interference from other wireless devices in the area, of which lately there are plenty!

Then your main concern is voltage drop. This can be a big problem with direct current (DC - like a car uses) and not so much of a problem with alternating current (AC - like a house or wired doorbell uses). Best if everything running in long wires is AC.

And voltage drop is more so a problem when there is a large amperage (wattage) load at the end of the long length of wire - like an air compressor.

The good news is that a relay uses very little amperage (wattage).

You would combat voltage drop by using larger gauge wiring. However note that an AC wired doorbell (low amperage load) can use pretty small wire for a long distance and still work just fine.

Anyway find out the voltages being used. If it is AC or DC. And the load at the end in amperage. Then use a voltage drop calculator like the following which is AC and DC. (For AC use single phase)...
http://www.nooutage.com/vdrop.htm

Watts to amps calculator...
http://www.supercircuits.com/resourc...Amps-Converter

Then you can also test your wiring along with the device. Just connect your power source, the switch, and the relay or whatever at the end of 100 ft of the wire you are going to be using. Make sure it works. Or even double the length. Also you can use a voltmeter to measure the voltage (under load) at the end of the wire.

To learn more about this, following is a wire size chart for DC automotive use. Note how DC wire size must be QUITE large for very small runs and the load or amperage also determines the size...
http://www.offroaders.com/tech/12-vo...gauge-amps.htm

And you can read more about DC wire size problems by reading about solar power which uses DC.

Missouri Bound 10-03-2012 10:23 AM

When low power relay systems were used originallly there was a relay panel most commonly located near the electrical distribution panel. This allowed convenient wiring access and a place to over-ride the relay if there was a failure. Then the low voltage wires could be strung independantly of the line voltage wires. If you choose to build your own relay panel you can find relays at Grainger which will work and it's very unlikely that they will become obsolete. Remote switching is very popular in industrial situations.

andrew79 10-03-2012 10:31 AM

We do a lot of lighting relay work. It will cost you more to locate all the relays at a central location but will be easier to maintain and troubleshoot down the road. Factor in voltage drop as you would normally. Unless your really loading down the circuit 100 feet shouldn't be a big issue.

ddawg16 10-03-2012 10:44 AM

Trade off's....

Like Andrew said, easier maintenance if the relays are located in one location.....

However...

In some cases it's easier to put the relays at the point (or close to) the point of use. Say you have 3 lights over in one corner that are powered from the same CB. You run one AC line to that corner..put your 3 relays there (in a box of corse)....then your only having to run the small DC control wires to the relays.

On a personal note....I wouldn't discount the longevity of wireless....

I'm in the middle of a 2-story addtion right now....automation is in the future plans....so I am putting in wire as needed just in case.....but I have two options...wireless and wired....I already have wired.....there are plenty of systems out there that transmit the control signal over the existing AC wire in your house.

Missouri Bound 10-03-2012 10:49 AM

I also think that wireless is a good way to go. May I suggest you get an X10 starter kit just to see what it could do for you. I know that Insteon is popular and may be more reliable than X10 but a small investment may help you in making a decision. Hard wire will be more reliable, 100%, unless there is a failure of component and that isn't very likely. It's just that wireless is completely flexible and as one of the other posters stated it's portable. I"ve been using an X10 system for 15 years and 75% of my lighting is controlled by computer or motion detector.:whistling2:

Jackofall1 10-03-2012 11:05 AM

Run your low voltage to a locally mounted relay, as the low voltage wiring is far less expensive than the load wiring for 120V wiring circuits. But as others have said wireless is the latest, no wiring runs from the controller.

Mark

sparkyjake 10-03-2012 11:40 AM

If you are concerned about future proofing, like I am when I do exactly what you are doing to my future home, I would run all the low voltage in "Smurf" tube which is rated for line voltage.

This way, in 20 years if you give on low voltage or want to add a dimmer, you can pull the low voltage out and 120 volt in.

Jackofall1 10-03-2012 11:44 AM

Quote:

Originally Posted by sparkyjake (Post 1022869)
If you are concerned about future proofing, like I am when I do exactly what you are doing to my future home, I would run all the low voltage in "Smurf" tube which is rated for line voltage.

This way, in 20 years if you give on low voltage or want to add a dimmer, you can pull the low voltage out and 120 volt in.

Great idea!

gstein67 10-03-2012 05:21 PM

Thanks for all the great insight and feedback!

The lighting runs would be standard 120VAC. I appreciate the note confirming maintenance of the relay boards. Maybe I'll arrange the house wiring design to have two or three relay panel boxes, arranged strategically about the house to avoid a whole bunch of long runs. This would follow ddawg16's point about stringing cheaper bell wire control lines, and one or two breaker'd high power lines.

The smurf tube is a good thought, for future-proofing.

If I do any wireless, I'm looking at Zigbee-based products. I'm going to try and minimize/eliminate them for reliability, however.

Again... thanks!

Missouri Bound 10-03-2012 07:50 PM

That won't shorten the runs.:no: You still have to run the power to the relay first, no matter where it is. Different relay points will just be stopping points for the circuit. And you need to run the hot, neutral and ground wires together anyway.


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