4 Plug Powerbar Extender

 
This was a DIY project that I made a few months back. It is an enhanced version of the Original Single Plug unit that I made last year, I decided to make the 4 plug version look a bit neater and be more functional in itís design. This particular unit was made to get around a nagging problem I had with my local power being 50 Cycle and having to use USA 60 Cycle powerheads and pumps. I made this so that the Main plug is plugged into my 60 cycle Inverter system and the controller which is on 50 cycle can control each 60 cycle plug. An Extender like this is more commonly used for the purpose of protecting your controllerís powerbar from the heavy loads when using devices like Chillers\Heaters and MH Lighting. The only change is the Gauge wire that you might want to use in making it. I used a medium gauge but you could use heavier wiring if needed. The Relays are each rated at 10 Amps so that is about 1100 Watts of power. Theoretically you could make this unit with the ability to control 4000+ Watts of power.
 
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Scrounging around my garage I came across this old Fridge power saver box. It was rusted and in really sad looking condition but it did have one big plus that made it all worth while
 
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The heart of the system, a 10Amp 120Volt Radio Shack Relay. I looked around the garage looking at old plug strips and UPS cases trying too find something that was small and could make a nice case
 
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Once I saw that 4 relays could fit so neatly into this case, it was the obvious choice.
 
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I drilled out the four holes for the 110V control plugs. The larger hole is for the 3 prong heavy duty power cord that will plug into the Main power. I sized the four smaller holes so that standard gypsum board plastic screw plugs could fit in tightly, I then cut off the excess and put a little epoxy on it. These plugs are ideal for preventing the control wires from rubbing against the metal casing
 
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Next I sanded the case smooth then primed and spray painted the inside, the outside is left unpainted but primed, until everything is done. I then put down a strip of Tape Velcro under the relays and on the case, so the relays cannot be shifted in the case. Next I started soldering on the Control wires; these are very light duty tape recorder 110V power cables. I just cut off the tape adapter end and soldered the wires on. BTW make sure to have flux and heat shrink tubing on hand.
 
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Then came the main power wire, it should be looped around the holes in the relay pins. Donít depend on just solder to keep any of the wires in place! After one loop around I Solder them and push up the heat shrink tubing then loop over to the next relay. This gauge of wire should be able too handle at least 1200+ Watts spread across all 4 plugs.
 
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At this point it starts getting very tight inside; soldering now becomes a very delicate operation As you can see the soldering iron nicked the Black wire, I fixed that in the end, but it's a bit of a challenge to solder with all these wires so close.
 
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Here is one of the 33K resistors about to be soldered on the ďPositive / HotĒ side of the Relay. After soldering it down I push the shrink tubing over the whole resistor
 
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Here you can see the finished relay wiring. All resistors are covered and everything is very secure. You donít want a wire flying off and shorting.
 
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Next I used the two house sockets that I purchased and cut the Joining Pins. If you look at the bottom half of the picture you can see how a little piece of copper bonds the two plugs together at the top. Once you cut the copper (On both sides of the plug **) the two plugs are electrical separated. Now I can power each plug individually
 
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I chose sockets that allowed wires to be pushed in from the bottom as well as attached from the sides, it seemed best that I kept all my options open.
 
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At this point I drilled out a hole in the top cover for the main fuse. Right after I took this photo I realized the white (Neutral wire) was on the fuse, so please donít make that mistake. Use the Black ďHot/Positive wireĒ. I had to unsolder the wires and redo it. You can see the last 33K resistor is tucked under the shrink wrap and the little blue wire is headed for the LED.
 
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This is what all the wiring looked like when it was almost done. Itís a very tight fit but I really like to make all my projects as neat and small as possible. If you decide to build one of these you should probably use a bigger case, it would be much easier to work with. Note: Each LED has a tiny piece of heat shrink tubing on each pin and then a larger piece goes over the whole thing.
 
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All fit up and finished.
 
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At night the lights look pretty cool, they let me know instantly what devices are being powered. The main Yellow LED indicates that main power is reaching the relays and that the fuse is not blown. The Extra Red LED by the Yellow is there for a future addition.
 
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The schematic is laid out in an easy to follow fashion, so that anyone with a bit of DIY soldering skills should be able to make their own unit. You can also easily modify this to make a unit with as many plugs as you want. Note: The Anode or positive side of the diode can be identified by itís slightly longer pin, that is the pin that goes to the resistor
 
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Parts List
 
  • Suitable case for your application
  • (4) x Radio Shack 110 Volt - 10 Amp Relays.
  • (5) x 33K Ohm ¼ watt Resistors
  • (5) x Small LEDS
  • (2) x 110V Household Plugs
  • (4) x Low power 2 prong power cables. Can be cut off old junk equipment or purchased
  • (1) x Heavy duty 3 prong power cable. Can be removed from a old UPS or even PC power cable
  • (1) x Round fuse holder (Amp rating per your requirements)
  • (1) x Fuse (Amp rating depends on your wiring size and application)
  • Heat shrink tubing, 3 sizes (small diameter for each LED pin 1mm) and the other depends on the size of your wires)
  • Flux.
 
Safety Note:
I take no responsibility for anything; this project involves high voltages that could be lethal. Please be very careful when building this, it can give you a rather nasty shock. I suggest that you donít plug in the main power or control power until you have confirmed correct wiring with an Ohm meter. I then recommend using a very small fuse (1/2 A) in the fuse holder and do a live test using a 30 watt lamp.