Next we will wire in each of the 8 black wires to the left-hand terminal for each relay. Carefully bend, cut and strip each of the black wires to fit exactly into the corresponding terminal on the relay board. You will want to connect them to the left hand hole of each terminal. (The right hand holes will not be used in this project) Remember to only strip about 5 mm of insulation so that all of the exposed wire will neatly fit into the terminal.



Safety note here! Make sure the power cord is not plugged in while you're working on it!



Now we'll wire in the power cord. I used an old computer cord for mine, mainly because I had a few laying around with nothing to do and because the cord was round which makes it easier to fit into a drilled hole (1/4" drill bit was a perfect fit). As an added bonus, the computer cord has color-coded wires inside so it is easy to tell which is the hot (black), the common (white) and the ground(green.) If the cord you're using does not have the nice color coding, don't worry, it's easy to tell with a multimeter.



(Refer to second picture for this step) Drill a hole in the bottom of the box and insert your power cord 20 cm or so. Very carefully remove the outside casing to expose the three insulated wires inside. Make sure that you knife did not remove any insulation on the individual wires. You may also want to wrap electrical tape several times around the cable just as it enters the box to prevent it from being pulled back out through the hole.



Now we'll connect the power cord to our relays.



The only hard part here is getting all of the red wires connected together. Since the red wiring nuts are too small to fit all of the wires, we will split the red wires up into two groups with a short section of 18AWG wire connecting the two together.



The goal here is to get the black wire from the power cord connected to all of the red wires. The trick to using a wire nut is to have all of the wires stripped the same amount and have them terminate together. (Except stranded wires such as those coming from the power cord can extend a little longer than the solid ones, that way the strands wrap around the solid wires binding them together inside of the nut.) Make sure to twist the wire-nuts good and tight, you don't want them popping out on you.



The white wire is straight forward, just wire it up to the extra white wire that you left hanging out the the last receptacle. (Use a smaller wire nut for this step if you have one.)



Also notice (in the 3rd picture) that I used 3 short pieces of green wire to chain together the ground screws and connect them to the green wire from the power cord. The ground connection is important for safety.















