loftygoals
Well-Known Member
So I made a flip box today and took some pics as I sent along. The idea was to make it as cheap as I could... came to £13.86 and took 39 mins according to the timestamps on my pictures.
Here's the finished flip box. The relay could handle 30A @ 240V (7200W max) but a single UK socket is only rated at 13A @ 240V (3120W) so that would be the max load this could handle per side in this form (I guess you could hard wire it if you wanted more load capacity... but if you were willing/able to do that you probably wouldn't be reading my crappy DIY). Anyway for my LEDs that is more than adequate. If you're thinking of powering HID lights you need to be aware of start up loads and should be using a contactor instead of a relay.
Parts list:
2 mains extensions leads (any length will do - I used 0.5m cords which were £1 each at poundland)
DPDT relay (I used a JQX-12F relay which is suitable for 240V and rated at 30A. It cost £3.32 from ebay)
Some spade connectors or a relay socket depending on your relay (I had these laying around)
4 cable glands (I used 25mm glands which were £1.77 for a 2 pack at screwfix)
Plastic project box (£5 off ebay)
A single piece of terminal strip (I had this laying around)
A mechanical timer is also needed to control the power flipping
To assemble you'll also need:
Drill and drill bit suitable for your cable glands
Screwdrivers
Cable cutter
Cable stripper
Crimper - depending on whether you're using spade connectors or a relay socket you might not need this
How it works:
It's worth understanding what you're trying to do before you start. You apply your voltage through the coil and it opens/closes a switch in the relay. You're using this to turn on/off sockets which you attach to the NC/NO terminals.
NO means normally open. That means the circuit is normally open like a light switch turned off. Normally means when no power goes through the coil. When you put power through the coil the switch flips and your circuit on that side of the relay goes from open (off) to closed (on).
NC means normally closed. That means the circuit is normally closed like a light switch turned on. When you put power through the coil the switch flips and your circuit goes from closed (on) to open (off).
So with no power through the coil the NC side of the relay is ON and the NO side of the relay is OFF. Once you put power through the relay it flips and the NC side of the relay turns OFF and the NO side of the relay turns ON.
This gives you a good idea of what happens (this pic is upside down compared to the earlier DPDT pic):
Now you have some understanding of what happens lets get started.
Step 1:
Drill holes in your box for the cable glands and check they fit ok
Step 2:
Cut your extension cables in half. You'll start by connecting up the plug ends. Take one and attach your Live to one side of the coil and your Neutral to the other side of the coil.
Here's a closer shot:
As you can see I haven't touched the earth yet. All the earth wires will be connected together towards the end and don't go into the relay.
Step 3:
Then take the plug end from the other extension cable you cut in half. You need to connect the Live and Earth to the COM sockets. At this stage I also connected up the earth cables via a section of terminal stip.
Step 4:
Then take the socket ends and push them through the cable glands at the bottom. Connect the Lives all on the same side and the Neutrals all on the same side. It should look something like this:
Step 5:
Connect up the grounds together via the terminal block. Your box should look something like this:
Then close the case.
Step 6:
Ideally you should use a proper socket tester which will tell you whether you've wired things up safely. Hopefully it'll tell you the wiring is correct. Test both sides:
The plug connected to the coil controls whether your power is shifted to the sockets on the Left or Right. The plug connected to the COM pins controls whether there is any power or not. So you attach a timer like this:
That's it. You have a flip box for under £15 in less than an hour of your time. You should probably mount the box and sockets to the wall for security.
Here's the finished flip box. The relay could handle 30A @ 240V (7200W max) but a single UK socket is only rated at 13A @ 240V (3120W) so that would be the max load this could handle per side in this form (I guess you could hard wire it if you wanted more load capacity... but if you were willing/able to do that you probably wouldn't be reading my crappy DIY). Anyway for my LEDs that is more than adequate. If you're thinking of powering HID lights you need to be aware of start up loads and should be using a contactor instead of a relay.
Parts list:
2 mains extensions leads (any length will do - I used 0.5m cords which were £1 each at poundland)
DPDT relay (I used a JQX-12F relay which is suitable for 240V and rated at 30A. It cost £3.32 from ebay)
Some spade connectors or a relay socket depending on your relay (I had these laying around)
4 cable glands (I used 25mm glands which were £1.77 for a 2 pack at screwfix)
Plastic project box (£5 off ebay)
A single piece of terminal strip (I had this laying around)
A mechanical timer is also needed to control the power flipping
To assemble you'll also need:
Drill and drill bit suitable for your cable glands
Screwdrivers
Cable cutter
Cable stripper
Crimper - depending on whether you're using spade connectors or a relay socket you might not need this
How it works:
It's worth understanding what you're trying to do before you start. You apply your voltage through the coil and it opens/closes a switch in the relay. You're using this to turn on/off sockets which you attach to the NC/NO terminals.
NO means normally open. That means the circuit is normally open like a light switch turned off. Normally means when no power goes through the coil. When you put power through the coil the switch flips and your circuit on that side of the relay goes from open (off) to closed (on).
NC means normally closed. That means the circuit is normally closed like a light switch turned on. When you put power through the coil the switch flips and your circuit goes from closed (on) to open (off).
So with no power through the coil the NC side of the relay is ON and the NO side of the relay is OFF. Once you put power through the relay it flips and the NC side of the relay turns OFF and the NO side of the relay turns ON.
This gives you a good idea of what happens (this pic is upside down compared to the earlier DPDT pic):
Now you have some understanding of what happens lets get started.
Step 1:
Drill holes in your box for the cable glands and check they fit ok
Step 2:
Cut your extension cables in half. You'll start by connecting up the plug ends. Take one and attach your Live to one side of the coil and your Neutral to the other side of the coil.
Here's a closer shot:
As you can see I haven't touched the earth yet. All the earth wires will be connected together towards the end and don't go into the relay.
Step 3:
Then take the plug end from the other extension cable you cut in half. You need to connect the Live and Earth to the COM sockets. At this stage I also connected up the earth cables via a section of terminal stip.
Step 4:
Then take the socket ends and push them through the cable glands at the bottom. Connect the Lives all on the same side and the Neutrals all on the same side. It should look something like this:
Step 5:
Connect up the grounds together via the terminal block. Your box should look something like this:
Then close the case.
Step 6:
Ideally you should use a proper socket tester which will tell you whether you've wired things up safely. Hopefully it'll tell you the wiring is correct. Test both sides:
The plug connected to the coil controls whether your power is shifted to the sockets on the Left or Right. The plug connected to the COM pins controls whether there is any power or not. So you attach a timer like this:
That's it. You have a flip box for under £15 in less than an hour of your time. You should probably mount the box and sockets to the wall for security.
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