Turning your lights on and off with your misting timer
The DIG 5006-IP propagation timer is a great misting timer that can be used for much more than controlling your misting system.
Many customers have contacted me asking how they can use their misting timer to control other devices. They want to use the built in reliability of the timer to automatically turn on or start items that use standard 110 volt electricity. What kinds of items are they asking about?
- Do you have a greenhouse that you want the lights to come on at a certain time?
- Do you have a small water pump that you want to be controlled by your timer?
- Do you have a water fountain that you want to turn off at night?
These chores and others can be accomplished by purchasing a simple device that gets wired into the system. This device is called a relay, a $17.00 item at my local electrical supply outlet.
What is a relay?
Well, I will let Wikipedia tell you what a relay is, but this is what they can be used for:
- Control a high-voltage circuit with a low-voltage signal, as in some types of modems or audio amplifiers,
- Control a high-current circuit with a low-current signal, as in the starter solenoid of an automobile,
- Detect and isolate faults on transmission and distribution lines by opening and closing circuit breakers (protection relays),
- Time delay functions. Relays can be modified to delay opening or delay closing a set of contacts. A very short (a fraction of a second) delay would use a copper disk between the armature and moving blade assembly. Current flowing in the disk maintains magnetic field for a short time, lengthening release time. For a slightly longer (up to a minute) delay, a dashpot is used. A dashpot is a piston filled with fluid that is allowed to escape slowly. The time period can be varied by increasing or decreasing the flow rate. For longer time periods, a mechanical clockwork timer is installed.
- Isolate the controlling circuit from the controlled circuit when the two are at different potentials, for example when controlling a mains-powered device from a low-voltage switch. The latter is often applied to control office lighting as the low voltage wires are easily installed in partitions, which may be often moved as needs change. They may also be controlled by room occupancy detectors in an effort to conserve energy,
- Logic functions. For example, the boolean AND function is realised by connecting normally open relay contacts in series, the OR function by connecting normally open contacts in parallel. The change-over or Form C contacts perform the XOR (exclusive or) function. Similar functions for NAND and NOR are accomplished using normally closed contacts. The Ladder programming languageis often used for designing relay logic networks.
- Early computing. Before vacuum tubes and transistors, relays were used as logical elements in digital computers. See ARRA (computer), Harvard Mark II, Zuse Z2, and Zuse Z3.
The first point; using low voltage to control a higher voltage, is what we are interested in. Using the low voltage timer to turn on higher voltage devices is exactly what we want to do.
Which relay should I purchase to use with my misting timer?
Good question, and one that I am not qualified to answer. I am not an electrician so I cannot tell you which relay to purchase. I myself had to call a licensed electrician for advice. He asked me what I was controlling with it so he could recommend a relay that can handle the voltage and more importantly, the amperage. When I told him I wanted to control a few lights, he calculated the amperage, and what he told me to get is a “relay in a box” , also called a RIB.
- This relay uses 10-30 volts AC (the low voltage part of the relay), which is perfect for use with the DIG 5006-IP misting timer because it has an output of 24 volts AC.
- This relay controls 120 volts AC, which is standard household voltage in the US.
- The relay is a single pole double throw which is what I need to turn my lights on and off.
- The relay is rated for 10 amps, plenty for the few lights I want to control.
When I told him I would be controlling three 60 watt bulbs, he used the following formula to figure the 3 bulbs would be using about 1.5 amps which is well below the 10 amps the relay is rated for.
Formula: Watts/Volts = Amps
So, three 60 watt bulbs equals 180 watts
180 (watts) divided by 120 (volts) (actually 110, but using the 120 the relay is rated for) =1.5 amps
So using that formula, I could safely use the relay to control six 60w bulbs (the electrician figured that all out, not me!). At this time, I have no intention of adding three more bulbs so I am safe using that relay.
When consulting the electrician on which relay you should purchase, be sure to tell them the exact devices you want to control, and be sure to stick with your plan. Also be sure to let them know if you plan on adding devices at a later date. They will let you know how many and what kind of devices you can safely use. Do not assume you can just keep adding more lights, fans, pumps, or whatever to the circuit. Drawing more than the rated amperage may damage the relay, or worse, cause a fire. It would be much safer to just purchase a new relay to use for the new devices.
The relay I purchased to control my lights
The relay I purchased is a RIBU1C. The great thing about this relay is the fact that it can be controlled by multiple input voltages, 10-30 volts AC or DC. This means that if you have a misting timer that has an output of 24 volts DC, which is the most common voltage used to operate a solenoid, you can use this relay to turn your lights, fans, etc on and off. Another great feature is that it has a light to indicate that the relay is being activated by the timer.
Figuring out the wiring
I have to be honest and tell you I know just enough about electricity to get me shocked or killed. I can replace outlets, switches, lights, and other stuff, but when it comes to figuring out how to correctly wire up something like this relay, I am stuck. I mean, take a look at the number of wires sticking out of the bottom of that thing! I looked at the wiring diagram that is on the relay, but I had no idea how to properly wire it. I took it to a friend of mine who is a licensed electrician, and in five minutes he had explained how I need to connect the wires to control my lights.
With this relay, I will have 24 volts AC operating the “switch” inside the relay that will allow the 110 volts AC (household current) to pass through and to my lights. Looking at the diagram, I needed to use the White/Blue (10-30 volt AC/DC) and the White/Yellow (Common) wires. These wires are to be connected directly to my misting timer (DIG 5006-IP) under one of the numbered “zone” screws and the common “C” screw respectively.
NOTE: The relay will be considered a zone by the timer. This relay has another wire that is White/Black but this wire will not be used at this time.
The other wires that will be used are the Orange and Yellow. The Yellow being the common wire and the Orange because it will carry the power once the switch in the relay is activated. This is called a normally open circuit, meaning that there is no power being delivered to it without the switch being activated because the contact is normally open. The Blue wire MUST be capped of when not being used!
To make this a bit easier to understand, think of a light switch. When the switch is off, the electrical contact inside it is open, not allowing electricity to pass. When you flip the switch to the on position, the contact inside closes, allowing the electricity through and to your lights. The relay works exactly the same way, if the timer does not send a signal to the relay to flip the switch, the lights will remain off. When the timer sends a signal to the switch, electricity is allowed to pass on to your lights, turning them on.
Another even simpler way to look at what normally open means is this: you have two wires and each has the ends stripped to the bare copper. One wire comes from an outlet and the other goes to a light. If you do not touch the two bare wires together, the light will not turn on (normally open). However, once you touch those two bare wires together you have closed the gap and allow electricity to pass which will turn on the light. NOTE: Do not actually try the bare wire example, you could get a nasty shock!
See the following picture to see how a light switch works and it’s relationship to the bare wire example:
So to be clear, I used the White/Yellow and White/Blue wires to go to the timer and the Orange and Yellow wires to go to the lights.
How I mounted the relay
Take a look at the following picture:
Notice that I used two separate electrical boxes that are attached by a small nipple, then mounted the relay on a box? I did that to keep the lower voltage (24 volt) and the higher voltage (110 volt) separated. This make things safer and easier to work on. These items can be purchased at any local hardware or home improvement store. Remember, these boxes are NOT waterproof and will need to be installed in a safe location.
The following picture also shows the relay mounted on an electrical box and that box attached to another with an electrical nipple. I have let the wires fall outside the boxes so you can get a better view of them.
How I wired the relay to the misting timer and lights
I took the White/Blue and White/Yellow wires and passed them through the left box and through a clamp I installed in the bottom of the box. The White/Black wire will not be used so I simply coiled it up inside the box.
Next, I ran the Yellow, Orange, and Blue wires through the nipple that connects the two boxes together. I capped off the Blue wire with a wire nut because it will have a constant supply of power and I do not want it to come in contact with the box itself, and coiled it inside the box.
I then installed wire clamps into the bottom of both boxes and took the wire that goes to my lights and brought it into the box on the right, cut it, and stripped the wires. This may need a bit more explanation for some, so I will show a diagram of what I mean. REMEMBER to turn off the breaker, unplug the cord, or whatever else you need to do to make sure no electricity is passing through the wire before cutting it and running it into the metal box!
Wiring the lights to the relay
Next I started to connect the wires. I made sure the power to the lights was OFF and even better, I turned off the breaker!
Working in the electrical box on the right, one of the bare copper wires was wrapped under a screw in the bottom of the box and then the two bare wires were wire nutted together. The White wires were also wire nutted together.
Next, the Blue wire was wire nutted. No wires were connected to it, I simply twisted a wire nut onto it and tucked it into the box. This wire MUST have a wire nut on it to prevent it from shorting out and possibly giving someone a shock!
Next, I took the Orange wire and connected it to one of the Black wires with a wire nut. I then took the Yellow wire and connect it to the remaining Black wire with a wire nut.
Wiring the misting timer
The misting timer was the easiest part of all the wiring. I simply removed the cover to the timer and wired it like this:
I used the two wires that came out of the bottom of the left electrical box. This is the White/Blue and White/Yellow wires. The White/Black wire was tucked into the box because it was not used. The White/Yellow wire was placed under one of the screws marked “C” on the left. The White/Blue wire was placed under one of the numbered screws on the right. This number corresponds to the zone the timer will be turning on and off.
See the following picture to see what the wiring now looks like:
All that is left is to program the zone to turn the lights on and off, and install covers onto the boxes!
After programming the correct zone, (detailed instructions for programming the DIG timer can be found at Mistkits) I sat back and waited for the timer to turn on the lights. After a minute or two, I heard a click from the relay and saw the red light was on, indicating that power was now getting to my lights. I then looked at my lights and saw that they were on. Success! (The following pictures shows the red light on. I took it before mounting the relay to the electrical boxes.)
DISCLAIMER: I am not a licensed electrician and these instructions are for educational purposes only. Be sure to seek the advice of an electrician before attempting to wire your own relay!
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