Wiring for porch downlighters, do I need a ceiling rose?

[piper64]

I'm planning to put two downlighters in my porch and am running a cable off the consumer unit to a 20A junction box in the porch roofspace. I'll daisy chain the downlighters with two core lighting pendant cable.

Do I need to run a cable to a ceiling rose from the junction box, then run a two core lighting pendant cable to the first downlighter from the ceiling rose or could I simply run the two core lighting pendant cable straight from the junction box to the first downlighter?

 

[Taylortwocities]

Your junction box is your "ceiling rose"!

Two points.

1. You'll need 3 core to the downlights - your cable must include an earth (cpc).

2. As your juction box and cables will not be attached to the structure, your juction box must provide strain relief for the cables. One of these would be typical: http://www.tlc-direct.co.uk/Products/ASJ804.html

or one of those "Dragons Den" choc boxes http://www.tlc-direct.co.uk/Products/CHOCBOX.html

 

[piper64]

Thanks.

The JB is attached the wooden structure of the porch roof and the cables clipped to the same.

The downlighter only has blue and brown connections, so what do I do with the earth if I use 3 core?

 

[Chri5]

If the porch is an open type you should consider ip rated fittings.

 

[Iggifer]

The downlighter only has blue and brown connections, so what do I do with the earth if I use 3 core?

Where the arm for the connector block screws to the white/chrome/whatever bit you can see is where you connect the earth to (using an eyelet crimp is the easiest method)

 

[piper64]

If the porch is an open type you should consider ip rated fittings.

It's a block built enclosed porch.

 

[piper64]

The downlighter only has blue and brown connections, so what do I do with the earth if I use 3 core?

Where the arm for the connector block screws to the white/chrome/whatever bit you can see is where you connect the earth to (using an eyelet crimp is the easiest method)

http://www.diy.com/nav/decor/lighti...cessed-3-Pack-Fixed-White-Downlights-10867764

The arm is connected the block with odd screws that have a triangle instead of a phillips or slot head. The arm itself attaches to the circular bit just by slotting on.

http://www.diy.com/nav/decor/lighti...lb-and-Connector-Kit-Eco-Halogen-40W-10867757

I could possibly find normal screws the same size and use them instead, if I can undo the current ones, but am concerned that the fitting instructions don't make any mention of an earth being needed, just the twin core pendant cable.

These lights are double insulated, so no earth required, apparently....

 

[Taylortwocities]

Thanks.

The JB is attached the wooden structure of the porch roof and the cables clipped to the same.

It must be accessible as it has screwed connections. How will you get at it after the installation is finished and a problem occurs with your JB??

The downlighter only has blue and brown connections, so what do I do with the earth if I use 3 core?

The downlight may only require live and neutral connections to operate but the CABLE requires an earth (cpc) connection from the JB to the downlight. If the downlight is double insulated then the earth does not connect to the downlight, but it must be there.

How were you planning to test and verify the EFLI after the installattion if there isn't an E present?

 

[piper64]

The JB could be mounted in the box that houses the Consumer Unit rather than in the roofspace, it would be easily accessible then.

As far as testing the Loop Impedance, I hadn't considered it and I'm confused when you say:

"The downlight may only require live and neutral connections to operate but the CABLE requires an earth (cpc) connection from the JB to the downlight. If the downlight is double insulated then the earth does not connect to the downlight, but it must be there. "

What about a standard pendant? That's connected to the ceiling rose without an earth. How is this different?When you say that the earth must be there, but not connected but must be there, what do you mean?

Could you clarify?
Thanks

 

[rjm2k]

If you put the earth there even though its not used there are two advantages, firstly its there if you change to a light that does need it and secondly if you put a nail through the cable the rcd will detect the short to earth and kill the power as it will with other earth faults

 

[piper64]

If you put the earth there even though its not used there are two advantages, firstly its there if you change to a light that does need it and secondly if you put a nail through the cable the rcd will detect the short to earth and kill the power as it will with other earth faults

The earth doesn't actually connect to the downlight then? I connect all three wires at the JB, but just use the live and neutral to connect to the downlighter and tape the earth over at that end?

I was planning to daisy chain the two lights or do I run each light back to the JB? Alternatively, do I daisy chain the L and N, but join the earths together?

This is more complex that it seemed. As only 2 wires are used on the downlight, I assumed it was like wiring a pendant, except there's a downlight at the end instead of a standard bulb holder.

 

[piper64]

All gone quiet chaps?

 

[Taylortwocities]

Thought you had enough advice for one week.

OK, you can run separate cables from the JB to the two downlights
or#you can run one cable to the first light and then connect a second cable to go to the second downlight, with the earth being connected so it is continuous to the final light. (Because that is where you'll need to test the earth is there all the way through.)

Personally I would use the separate cable method as most downlights aren't easy to terminate two cables and a place to park the earth, unless you want to use ANOTHER JB, of course.

Don't forget my post re the JB, you don't want to screw it onto the woodwork unless it is accessible.

 

[ban-all-sheds]

As far as testing the Loop Impedance, I hadn't considered it

http://www.tlc-direct.co.uk/Book/8.6.2.htm

 

[piper64]

Thought you had enough advice for one week.

OK, you can run separate cables from the JB to the two downlights
or#you can run one cable to the first light and then connect a second cable to go to the second downlight, with the earth being connected so it is continuous to the final light. (Because that is where you'll need to test the earth is there all the way through.)

Personally I would use the separate cable method as most downlights aren't easy to terminate two cables and a place to park the earth, unless you want to use ANOTHER JB, of course.

Don't forget my post re the JB, you don't want to screw it onto the woodwork unless it is accessible.

You can never get enough advice.

The JB will be in the box that house the Consumer Unit, as it's on the wall that backs onto the porch. The cables for the switch and both downlighters will run from there, through the wall.
The earth going to each downlighter will be taped up as it's got nowhere to go.
thanks

(@ban all sheds, my wifes uncle is a sparky but usually too busy for family jobs. I'll get him to test the Loop Impedance if possible.)