Best way to wire in new GU10 fittings

Matteo2000 · Oct 25, 2017

Hi all,

I'd be grateful for some advice on how to wire in some new GU10 fittings. I bought these fire rated Minisun ones: https://www.amazon.co.uk/dp/B00GSPFK2O/ref=pe_3187911_185740111_TE_item

I will be removing the existing GU5.3 (MR16) fittings before starting. These fittings have a standard wiring: i.e. bulb to GU5.3 fitting to transformer to mains. The connection between the transformer and the mains uses wiring that's built into the transformer (i.e. two single wires, one each for live and neutral). The connection to the mains (which I assume is 2 core and earth) is done through a standard round junction box.

I'd like to know the best way to wire the mains to the new GU10 fittings once I've removed the transformer (and the GU5.3 fittings)

- Option 1: Is it safe to connect the mains directly into the choc box that is pre-attached to the GU10 fitting, i.e. removing the existing junction box and wiring the mains to the fitting? If I do this, the fittings are not class II, so I assume I would need to strip the mains wire sufficiently to be able to run the earth wire down to the metal body of the fitting. This doesn't seem very elegant to me, and I'm concerned that the external insulation will be gone and the choc box will only be gripping the wires themselves.

- Option 2: Would it be better to use Wago lighting connectors and a Wagobox? In which case, would I:

2A. Replace the choc box built into the GU10 fitting with a wagobox? I.e. by removing the existing junction box and then wiring both the mains and the bulb connector into the Wagobox. If so, would it matter that the wagobox was not fixed to the fitting, i.e. would this put stress on the connections? Or would it be better to attach the wagobox to the fitting, e.g. with a zip tie?

OR

2B. Use both a wagobox and the choc box on the GU10 fitting? I.e. by replacing the existing junction box with a wagobox, and then running a new wire between the wagobox and the choc box on the fitting. If so, what kind of wire would I need?

Thanks!!

Matt

telectrix · Oct 25, 2017

in your situation i would pre-flex the new fittings each with approx. 10" of 3 core 0.75mm flex. then connect the other end of the flex into the existing round JBs. making sure all connections are good. if the fittings have an earth terminal, use it. if not just fit a single choc block to the cpc.

J.C.E · Oct 25, 2017

telectrix said:
in your situation i would pre-flex the new fittings each with approx. 10" of 3 core 0.75mm flex. then connect the other end of the flex into the existing round JBs. making sure all connections are good. if the fittings have an earth terminal, use it. if not just fit a single choc block to the cpc.

he meant connector block

Cadgey123 · Oct 25, 2017

Pre wire your new fittings with Click flow connectors.

Easy and simple to connect up, and easy to change a fitting in future.

Matteo2000 · Oct 25, 2017

telectrix said:
in your situation i would pre-flex the new fittings each with approx. 10" of 3 core 0.75mm flex. then connect the other end of the flex into the existing round JBs. making sure all connections are good. if the fittings have an earth terminal, use it. if not just fit a single choc block to the cpc.

Thanks very much for this advice. I take this to be similar to my option 2B, but just re-using the existing junction box instead of using a Wagobox.

If I can't get the round junction boxes through the ceiling holes to re-wire them then presumably it would be fine to switch the junction boxes with wagoboxes (or click flow connectors)?

On the cable to use, I think I heard that it's not allowed to step down the diameter of the cable in a ceiling? In which case, wouldn't I need 1.5 mm cable rather than 0.75 mm flex? Or would 0.75mm be okay?

Thanks,

Matt

p.s. I've read that the GU10 fittings do have earth/cpc terminals.

Matteo2000 · Oct 25, 2017

Cadgey123 said:
Pre wire your new fittings with Click flow connectors.

Easy and simple to connect up, and easy to change a fitting in future.

Interesting suggestion thanks. I'd need a matching one to wire to the mains?

Octopus · Oct 25, 2017

what you do need to ensure is that the cpc is continuous from the fuseboard to each and every downlight.

Matteo2000 · Oct 25, 2017

Murdoch said:
what you do need to ensure is that the cpc is continuous from the fuseboard to each and every downlight.

Okay, thanks. How would I check that?

Octopus · Oct 25, 2017

Matteo2000 said:
Okay, thanks. How would I check that?

with a tester ...........

Matteo2000 · Oct 25, 2017

Murdoch said:
with a tester ...........

Okay, something like this?
https://www.amazon.co.uk/Multimeter...19031_1_1?s=diy&ie=UTF8&qid=1508959342&sr=1-1

telectrix · Oct 25, 2017

Matteo2000 said:
Okay, something like this?
https://www.amazon.co.uk/Multimeter...19031_1_1?s=diy&ie=UTF8&qid=1508959342&sr=1-1

you would need a long lead to reach the origin of the circuit as well. something like:
Electricians R2 15m test lead extension wander lead, Megger, Fluke, metrel etc | eBay - https://www.ebay.co.uk/itm/Electricians-R2-15m-test-lead-extension-wander-lead-Megger-Fluke-metrel-etc/181393042234?hash=item2a3bde2b3a:g:U7UAAOSwU9xUQjip

Cadgey123 · Oct 25, 2017

Matteo2000 said:
Interesting suggestion thanks. I'd need a matching one to wire to the mains?

Put male on the fitting and female on the mains wires.

Male pins goes out
Female pins goes inwards

Like humans

haptism · Oct 25, 2017

Those quick flow connectors save alot of faffing about, but thought why the male end does not exactly grip the cable(s) in place, whereas the female end does.

Taylortwocities · Oct 25, 2017

Matteo2000 said:
Okay, thanks. How would I check that?

When you do your EFLI test. With your EFLI tester.

Matteo2000 · Oct 25, 2017

Okay, thanks all. Presumably I can use a long length of cable in place of the dedicated one on eBay. I have no idea where to connect it on the consumer unit though!

On the cable to use between the junction boxes and the gu10 fittings, I just read elsewhere that if I use flex it has to be the same diameter as the existing twin and earth in the ceiling (at least 1 mm). Is this correct?

Thanks.

Taylortwocities · Oct 25, 2017

For that short length, 0.75mm flex will be fine.

Cadgey123 · Oct 26, 2017

Matteo2000 said:
Okay, thanks all. Presumably I can use a long length of cable in place of the dedicated one on eBay. I have no idea where to connect it on the consumer unit though!

On the cable to use between the junction boxes and the gu10 fittings, I just read elsewhere that if I use flex it has to be the same diameter as the existing twin and earth in the ceiling (at least 1 mm). Is this correct?

Thanks.

Sounds like you are playing with fire mate.
If you don’t know where to connect it to inside the consumer unit, you best shouldn’t be doing the job. Do go poking around in there it’s dangerous. Get a sparky to connect them for you.

Taylortwocities · Oct 26, 2017

Cadgey123 said:
. Do go poking around in there it’s dangerous. Get a sparky to connect them for you.

He means DON'T go poking…!

I was curious about this

Matteo2000 said:
I have no idea where to connect it on the consumer unit though!

There's nothing for you to do there. Why do you think there is?

richy3333 · Oct 26, 2017

Always worrying when the Amazon sales blur doesn’t show the instructions - won’t those things need fire hoods with standard lamps? Someone asked if they are rated for bathrooms and the seller replied ‘ask your electrician’! Cleary no idea on IP ratings etc.

Matteo2000 · Oct 26, 2017

Thanks all.

There are alternative versions of these lights which have IP ratings for bathrooms (which so don’t need).

I’m sure I can figure out the EFLI test. I just need to know if it’s not safe to use 0.75 mm flex. But it sounds like it’s fine.

Matt

Taylortwocities · Oct 26, 2017

richy3333 said:
won’t those things need fire hoods with standard lamps?

Only if they are in a fire-rated ceiling. That means a ceiling that forms part of a fire-compartment.
There isn't one in a normal house, except for the ceiling of an integrated garage. The ceilings of rooms in flats etc are a different matter.

Midwest · Oct 26, 2017

haptism said:
Those quick flow connectors save alot of faffing about, but thought why the male end does not exactly grip the cable(s) in place, whereas the female end does.

They do a version with cable grips, CT102C is one of them.

Midwest · Oct 26, 2017

Taylortwocities said:
Only if they are in a fire-rated ceiling. That means a ceiling that forms part of a fire-compartment.
There isn't one in a normal house, except for the ceiling of an integrated garage. The ceilings of rooms in flats etc are a different matter.

True enough, but your local building inspector would get pretty ----ed, if you removed the plasterboard and exposed the ceiling joists. The plasterboard is there for fire protection of the wooden joists, so cutting holes in it for non fire rated down lights, kinda defeats the object.

Electrical Safety First recommends that fire rated down lights are used in all ceilings. The cost between the two are minimal, so I can't see a reason not to install fire rated down lights as standard.

Mind you, no ones banging on about extractor fans in bathrooms...yet.

Octopus · Oct 26, 2017

Midwest said:
Electrical Safety First recommends that fire rated down lights are used in all ceilings. The cost between the two are minimal, so I can't see a reason not to install fire rated down lights as standard.

Which some people translate into mandatory - which is misleading to say the least...

haptism · Oct 26, 2017

Midwest said:
View attachment 38983
They do a version with cable grips, CT102C is one of them.

Great never seen those; this undoubtedly leads on to the question: if all cables entering accessories must to be secure, then why the design of the quick flow connectors without the clamps ? Are they designed for bigger cable, or rely on securing cable with a clip.

Midwest · Oct 26, 2017

haptism said:
Great never seen those; this undoubtedly leads on to the question: if all cables entering accessories must to be secure, then why the design of the quick flow connectors without the clamps ? Are they designed for bigger cable, or rely on securing cable with a clip.

Who knows, why hasn't my favourite dram got a Government health warning on it

richy3333 · Oct 27, 2017

Midwest said:
True enough, but your local building inspector would get pretty ****ed, if you removed the plasterboard and exposed the ceiling joists. The plasterboard is there for fire protection of the wooden joists, so cutting holes in it for non fire rated down lights, kinda defeats the object.

Electrical Safety First recommends that fire rated down lights are used in all ceilings. The cost between the two are minimal, so I can't see a reason not to install fire rated down lights as standard.

Mind you, no ones banging on about extractor fans in bathrooms...yet.

Sort of what I was thinking and then there’s the potential for insulation sitting on top of those fittings.
Apologies if I’m wrong but I gained the impression the OP wasn’t in the trade. I’ve yet to see a DIYer fit these lights correctly. Worst case being right against joists that were charrred due to the heat of GU10 lamps.