Light Replacement Failure -

izzop · 5 Jan 2021 at 15:43

Replaced a florescent strip light in the kitchen and failed miserably.

The fitting of it is fine, it's the wiring that has stumped me :confused:

When I removed the strip light it revealed two cables coming from the ceiling, which had the red and black separately paired into a block, the earth then went into its own block and was connected to the strip light fitting. The block with the read and black in had blue and brown coming from the other side going to the light.

The replacement light only has Live and Neutral, no earth. So what I did, rightly or not, was both reds into a block and then into the Live and the same with the black, paired into a block and a single into Neutral. The earths I paired and terminated in a block.

Once fitted, the light switched on, but on switching it off it would trip the fuse to which I have no idea as to why.

I will add that there's two light switches in the room, but I'm not sure if that should make any difference as all I've done is not connected the earth to the new light fitting as per the instructions which just show L & N to be fitted.

Any budding electricians, or someone that understands this better than me care to try to help me out?

Here is what is coming from the ceiling with regards to the wiring: -

These are the lights in question: -

https://www.diy.com/departments/hades-chrome-effect-mains-powered-4-lamp-spotlight/1703798_BQ.prd

200sols · 5 Jan 2021 at 16:12

How did you rewire it? Blue to black and brown to red? Did you take a picture before removing old fitting to identify which wire is the switched live? The switched live should have been sheathed to identify it.

izzop · 5 Jan 2021 at 16:31

Stupidly, no, I didn't.

From memory it was as I said, they were paired together and into a block, which then had a single blue and brown for the strip light. Unless I was mistaken, but certainly there was nothing sheathed to identify it was the switched live.

izzop · 5 Jan 2021 at 16:53

Hold on....

After sitting here thinking about it the red's went into their own type of block, a red in on either side. Going nowhere, just creating a loop, if that makes sense?

This confuses me further... Does this mean that both blacks would be separate and into L & N individually?

NoobCannon · 5 Jan 2021 at 17:16

*removed* one of the blacks a neutral and one a switched live. Or it could just be in series with another light, do you have more than one in the room?

however as i didn't remove it and have no idea how your house is wired i would advise you not to touch it further and get an electrician.

get an electrician, unless you have the confidence to work it out your self.

izzop · 5 Jan 2021 at 17:25

It's the only light in that room.

Yes, I think the only safe and sensible option is to get an electrician in.

mickyflinn · 5 Jan 2021 at 17:35

Im no expert but only going off this linked diagram join the 2 red wires together and the same with the earths . Connect the live from the lamp to one black wire and the neutral to the other black wire.

Brown is red live.
Blue is black neutral .

https://www.flameport.com/electric/lighting_circuits/lighting_ceiling_rose.cs4

Take a look and see if you get the same conclusion .

izzop · 5 Jan 2021 at 17:42

Arrive at the same conclusion, however...

I have no indicator as to which black is the live or neutral, consequences of getting those the wrong way around?

200sols · 5 Jan 2021 at 17:48

izzop said:
Hold on....

After sitting here thinking about it the red's went into their own type of block, a red in on either side. Going nowhere, just creating a loop, if that makes sense?

This confuses me further... Does this mean that both blacks would be separate and into L & N individually?

It makes sense, the blacks will be neutral and switched live the question is which is which..

I guess if not comfortable get a sparky in and next time take a picture before disconnecting. The switched live sheathing is often small or even omitted by bodgers.

izzop · 5 Jan 2021 at 17:50

200sols said:
It makes sense, the blacks will be neutral and switched live the question is which is which..

I guess if not comfortable get a sparky in and next time take a picture before disconnecting. The switched live sheathing is often small or even omitted by bodgers.

One was longer than the other! Certainly no sheathing on either, but as you say, which is which?

mickyflinn · 5 Jan 2021 at 18:08

izzop said:
Arrive at the same conclusion, however...

I have no indicator as to which black is the live or neutral, consequences of getting those the wrong way around?

Im guessing its do with the flow of current , on a standard light bulb fitting i dont think it would matter but if the light fitting has a transformer then issiues would occur.

Scrutinize · 5 Jan 2021 at 18:50

izzop said:
One was longer than the other! Certainly no sheathing on either, but as you say, which is which?

Do you not have a multimeter?

izzop · 5 Jan 2021 at 19:17

Scrutinize said:
Do you not have a multimeter?

Unfortunately not.

Beer_MonsterUK · 5 Jan 2021 at 19:22

izzop said:
Unfortunately not.

You're pretty much screwed. You could sort that out in 2 minutes with a meter. 1 twin & earth will be the incoming live and neutral, The other a live and switchwire. If you don't know which is which then it'll end up going pop. Only a small pop.

Scrutinize · 5 Jan 2021 at 19:27

izzop said:
Unfortunately not.

Can you get to a screwfix or toolstation?

This is an essential piece of equipment if doing electrical work really, even simple tasks.

Electricians wouldn't second guess it, even on a simple circuit rewire in case it wasn't wired correctly previously or there are aged issues.

izzop · 5 Jan 2021 at 19:38

Yes, have a local screwfix, best get myself one: -

https://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337

Certainly don't fancy second guessing.

Beer_MonsterUK · 5 Jan 2021 at 22:18

Get the cheapest meter you can find. you only need the continuity aspect of the meter.

bobuk · 6 Jan 2021 at 10:01

Perhaps this why people learn for a few years to become Electricians or maybe we should do away with any regulations and just ask a computer forum.

JRJ · 6 Jan 2021 at 10:07

I count myself as reasonably competent but I've still got to take a picture before disconnecting any blocks because god knows what the person before has done.

ZG002 · 6 Jan 2021 at 12:57

Ahhhhh.

The amount of times I've seen this over the years is un-real, so you aren't alone! You may have damaged your switch also (basically that is where you created a direct L-N short) it sometimes damages the switch.

But yeah, this light is probably end of line, two reds together, cpc together (earth) then your remaining blacks are neutral and switch live.

There is a cow boy way to tell which is which but I will leave you to get the correct equipment and check properly.