Making My Own Rig

[Spark123]

Has anyone got any diagrams how RCDs and main switches are wired up in a consumer unit? That would really help! Thanks!

A main switch in a consumer unit is just that, the meter tails (or supply) are wired directly into the main switch thus switching it off will kill the power (Line and Neutral) in the consumer unit with the exception of what is upline of the isolator i.e. the meter tails and the top of the isolator.

An RCD is a device which monitors line and neutral currents, in a healthy circuit the current flowing in the line must equal the current flowing in the neutral. If a fault occurs and current flows to earth either by the Circuit Protective Conductor (CPC) or via a person the current in the line will not equal that flowing in the neutral. If the fault current exceeds that of the RCD trip level it will trip and disconnect the power.

In a consumer unit which has an RCD protecting a number of ways it is important that all circuits connected into RCD protected ways have their Line connected to the MCB in the correct rail and their neutral connected into the correct neutral rail for that RCD, otherwise an imballance will occur and trip the device. The CPC should be connected to the correct numbered way in the consumer unit earth rail for identification purposes, this is usually just a single rail. Some RCDs have a fly lead which also connects to this rail.

 

[ban-all-sheds]

Im also going to get a 6A, 32A MCB for lighting and ring/radials.

I suggest 2 lighting MCBs - then you can explore the wonderful world of borrowed neutrals the painless way...

 

[Spark123]

With a dual RCD consumer unit?

 

[kiwiNCFC]

Im doing the 1st year of c&g 2330 lvl 2 1 day a week. Im 18 and already have a national diploma in electronic engineering but ideally want to go down electrician route.

Thanks for your replies, great help!

 

[kiwiNCFC]

For the supply cable do i need 3 core or 2 core cable flex cable with 5a fuse and where can i get one from?

 

[ban-all-sheds]

Every single wholesaler, DIY shed and high street hardware store in the country...

 

[kiwiNCFC]

Every single wholesaler, DIY shed and high street hardware store in the country...

lol i suppose i might go down b&q. Will i have to strip the earth wire out of the flex and put it in the earth terminal in the consumer unit?

 

[ban-all-sheds]

One of us is losing the plot here.

I don't think it's me.

The CU on your test board has to have a Line, a Neutral and an Earth connected to it.

Just like the one in your house does.

I don't see what the problem is.

 

[The Dentist]

Will i have to strip the earth wire out of the flex and put it in the earth terminal in the consumer unit?

I would suggest you do a lot more reading up on basic electrics before you attempt to make any physical circuits, otherwise you are likely to cause harm to yourself

 

[scousespark]

Given you are in your first year (assuming you now have 3 months college behind you) you should be concentrating on the theory.

I take it you have gone through the noddy stuff, fitting lights and scockets to a piece of ply with an old CU to pass thriugh the supply. Your lecturer will inspect your work, before you can plug in and switch on. If you do it at home, you won't have that backup.

You are 18 and have your whole life ahead of you. Take it one step at a time.

You stated

I did not even mention live testing, i just want to connect it up to see if a bulb lights up and switches on and off in 1 way and 2 way lighting etc, then i can test for continuity and inuslation resistance. I can still do this at home, by just getting 3 core flex and plugging it into the CU and wall socket.

This is plain wrong. Read up on testing and commssioning.
You do the dead tests, followed by the live tests. When all your tests are passed, you can plug in a lamp and stand back and smile when you see a brand new light.

At your stage, leave this to your time in college. Enjoy your training.

 

[sjwkmje]

When I was at college not that long ago we used 24V supplies fed around the rigs using purple ceeform connectors and 24V lamps. For some reason even though I was working at the same time and was safe working on 240V/415V circuits we could not use anything higher than 55V. It was not until my 4th year we started to use 240V/415V. Why not use 24V and play safe for a while?

Adam

 

[PrenticeBoyofDerry]

It's plain to see that kiwiNCFC is not ready to be making homemade rigs supplied by mains voltage.
Where did you get this idea from? surely not your tutors! if so they don't like you.
Do yourself a favour forget about the live testing and stick to theory and any practical assignments you get issued at college and a bit of dead testing, by the end of the term you should be better informed and instructed and still alive

 

[ebee]

You've already had some excellent advice - battery circuits!

Using batteries (or those little adaptors to cut the voltage to 12V or less) and lamps (bulbs) you can do all the different switching arrangements all the dead tests and all the functional tests safely without using mains voltages until you are certified "ready to fly"