garden light post installation

[pc_ef]

Hi. I am not an expert so forgive me for asking a rather simple question, but it's safer to check first. 

I have three garden light posts (say 1, 2 and 3), which I turn on/off from the garage. Installation uses armoured cable, red/blue/yellow. Question 1: is yellow earth? I thought armoured cable used the metal wires for earthing? 

The middle post (2) broke and had to get a new one. But this one only comes with cable red/blue from bulb and then a separate short piece of earth wire attached to a screw on the post itself.

So here comes the junction box question on post 2:  the connector will receive red/blue/yellow from post 1, and then send another red/blue/yellow to post 3. But to connect post 2 I only have red and blue going up to the bulb. The rather simple question about the earth wire is : 

a) should I connect the short piece of earth wire from the screw fitted on the post to the connector where the other earths are?

b) Or do I have to replace the new wire with one that has red/blue/yellow to match the others? And if so, where does the yellow go on the bulb side?

c) Or if the installation is earthed elsewhere, does the new post have to be earthed also, or can that be eliminated?

I hope this makes some sort of sense. 

Many thanks in advance, 

Pedro

 

[Lurch]

is yellow earth?

Could be.

I thought armoured cable used the metal wires for earthing?

It can be, depending on how/why etc.

As for the rest of the questions, ignore the colours. Connect the live to live, neutral to neutral and earth to earth. If you don't know which is which then it is probably not a job for you.