Problem of the week - ceiling rose

[springcrocus]

I have encountered this numerous times. The customer has removed a light fitting and unsuccessfully tried to replace it with a standard ceiling rose.

When I arrive, the ceiling rose is screwed in place and there are FOUR (normally three) red wires and FOUR (normally three) black wires hanging in mid-air. The four earths are correctly connected to the parking terminal. None of the wires, except the earths, have any identification sleeves on them.

Within ten minutes, I'm on my way and the customer is a happpy bunny.

Question - how do I sort the wires out and connect them correctly to the ceiling rose? Hint: start by turning the power off at the CU.

N.B. HSE would NOT approve of this method, and extreme care needs to be taken. However, it is quick.

(Note to Doc Hudson. As the Mod for this area, if you think this is promoting bad practice, kindly delete the post)

 

[steptoe]

errm, isnt it normally 2 blacks? or am I reading something wrong?

---------- Post Auto-Merged at 00:43 ---------- Previous post was made at 00:41 ----------

oh, I get it, but surely the number of blacks shouldnt be the same as the number of reds, esp if the number of cpcs is the same.

 

[batty]

You don't stick your tongue anywhere I hope.

 

[steptoe]

I have encountered this numerous times. The customer has removed a light fitting and unsuccessfully tried to replace it with a standard ceiling rose.When I arrive, the ceiling rose is screwed in place and there are FOUR (normally three) red wires and FOUR (normally three) black wires hanging in mid-air. The four earths are correctly connected to the parking terminal. None of the wires, except the earths, have any identification sleeves on them.

Within ten minutes, I'm on my way and the customer is a happpy bunny.

Question - how do I sort the wires out and connect them correctly to the ceiling rose? Hint: start by turning the power off at the CU.

N.B. HSE would NOT approve of this method, and extreme care needs to be taken. However, it is quick.

(Note to Doc Hudson. As the Mod for this area, if you think this is promoting bad practice, kindly delete the post)

I can get neons at a discount price if anyone wants to buy some.

 

[Apache]

errm, isnt it normally 2 blacks? or am I reading something wrong?

Do you not have a loop so 2 red and 2 black, and then a switch drop with another red and another black? So 3 red, three black? That's what we have here.

---------- Post Auto-Merged at 01:50 ---------- Previous post was made at 01:41 ----------

If I was in the position I would turn off CU, turn switch to 'on' and use a continuity meter to 'buzz' a pair as the switch drop (turning it back off to ensure I was correct. Suppose 4 wires could either be another light spurred or 2 way lighting.

By connecting a few wires together or using a long lead I could go along and work it out, but would take me more than 10 minutes. I'm guessing you have a trick?

 

[springcrocus]

Do you not have a loop so 2 red and 2 black, and then a switch drop with another red and another black? So 3 red, three black? That's what we have here.---------- Post Auto-Merged at 01:50 ---------- Previous post was made at 01:41 ----------

If I was in the position I would turn off CU, turn switch to 'on' and use a continuity meter to 'buzz' a pair as the switch drop (turning it back off to ensure I was correct. Suppose 4 wires could either be another light spurred or 2 way lighting.

By connecting a few wires together or using a long lead I could go along and work it out, but would take me more than 10 minutes. I'm guessing you have a trick?

Correct. :Applaud

---------- Post Auto-Merged at 08:05 ---------- Previous post was made at 07:59 ----------

I can get neons at a discount price if anyone wants to buy some.

Surely you mean your "approved voltage tester"

 

[Theorysparky]

i had a similar problem last week.....

my sparky mate 2 years ago was asked to put a light fitting up,which he did

it was a pain he said but had marked up all the wires for when they moved

well they were moving,,,,,my mate couldnt get back so he asked me to go (easy

 

[kerching]

errm, isnt it normally 2 blacks? or am I reading something wrong?---------- Post Auto-Merged at 00:43 ---------- Previous post was made at 00:41 ----------

oh, I get it, but surely the number of blacks shouldnt be the same as the number of reds, esp if the number of cpcs is the same.

Do you not remember 'back in the day'...double covered red singles. double covered black singles....I even go as far back as double covered singles and earth where the earth was also insulated!

Back in the day when cable was cable, electricians were electricians, Part P was a 'dream' [cough expectorate cough] and women were grateful.................. :run

 

[Manator]

Do you not remember 'back in the day'...double covered red singles. double covered black singles....I even go as far back as double covered singles and earth where the earth was also insulated!Back in the day when cable was cable, electricians were electricians, Part P was a 'dream' [cough expectorate cough] AND WOMEN WERE GRATEFUL.................. :run

I remember all of them but not that!!

 

[springcrocus]

Okay, now that some of our more senile senior members have had their little bit of fun with this thread, have any of our younger or less learned members had a chance to think about the original question yet?

(Patch, you're not included in the above remark and I'm sure you would work out the quick way after having to do it a couple of times.)

Please don't be sidetracked by the comments in some of the earlier posts, it's a straightforward question, no tricks, and remember you are not trying to fix a fault, just putting the wiring back where it should be.

In the real world, particularly if you're self-employed, it's all about getting the job done (safely and correctly) in the shortest possible time. Otherwise, you'll never have enough time to spend your hard-earned money.

Any takers?

 

[sellers]

well with the method you have described, I would guess its a standard loop in at the light with another live feed going off somewhere, so I would just find out the switch wire and connect up. If there were 2 lights in the room, I would preumse the extra twin would go to that.

---------- Post Auto-Merged at 18:55 ---------- Previous post was made at 18:50 ----------

also to add, I imagine quick way of checking would be to check for N-E resistance, find continuity on that and theres your feed.

Next look for L-N continuity, something very low 0.something is your switch, and then the other L-N would be your feed out, something like 500ohm or less

 

[Manator]

True but not the method used hence the opening statement.

 

[springcrocus]

well with the method you have described, I would guess its a standard loop in at the light with another live feed going off somewhere, so I would just find out the switch wire and connect up. If there were 2 lights in the room, I would preumse the extra twin would go to that.

Quite right, my friend, but the object of the exercise is to give some of our less experienced collegues a chance to try and sort out everyday problems i.e. one not encountered in the classroom. If all the professional electricians jump in with the answers, then it's all a bit pointless.

 

[Manator]

Quite right, my friend, but the object of the exercise is to give some of our less experienced collegues a chance to try and sort out everyday problems i.e. one not encountered in the classroom. If all the professional electricians jump in with the answers, then it's all a bit pointless.

I do understand what you are saying, but just by describing in real world environments both the fault and how it was detected and corrected will go a long way to help those who read these posts, so do not be too disheartened by input from experienced sparks, if they are the only ones to answer.

I would however encourage all training sparks to have a go, unlike in the classroom we are not going to take the proverbial out of you for getting it wrong.

 

[sellers]

one thing to note I wouldn't group younger with less experienced. Theres plenty of experienced young guys on this site.

 

[philbas]

one thing to note I wouldn't group younger with less experienced. Theres plenty of experienced young guys on this site.

Also plenty of inexperienced old guys, myself included

 

[adam1984]

I'm a student so ill give it a go.

Power off

Blacks together

Reds together

Turn light switch to on posistions

Continuity buzz check between Red 1 and Black 1, red 1 and black 2, red 1 and black 3 and so on until i got continuity bewtween live and switch live.

Sleeve appriottely and put remaining blacks in neutral and and reds in loop and Switch live in live at the rose.

Now thats how I would do it.

I had a little job on Saturday which was a problem light fitting and i was stumped at the amount of wires then realised that 1 was for the bathroom fan.

Let me know if i am in the right ball park??

Adam

 

[Theorysparky]

Thats how i would do it

couple of points

when you have found the live and switch live confirm this by turning switch off and testing again

if its two way switching a bit more switch flicking is required

 

[springcrocus]

I'm a student so ill give it a go.Power off

Blacks together

Reds together

Turn light switch to on posistions

Continuity buzz check between Red 1 and Black 1, red 1 and black 2, red 1 and black 3 and so on until i got continuity bewtween live and switch live.

Sleeve appriottely and put remaining blacks in neutral and and reds in loop and Switch live in live at the rose.

Now thats how I would do it.

I had a little job on Saturday which was a problem light fitting and i was stumped at the amount of wires then realised that 1 was for the bathroom fan.

Let me know if i am in the right ball park??

Adam

Not sure what you mean by "blacks together, reds together" but yes, your method would work but would not be quick. My question said FOUR of each, so that could be sixteen tests before youu found your switched live. Also, what is going to happen to your tests if another light has been left on before you powered down?

 

[adam1984]

I dont think it would take too long to do the continuity test to find the switch live, a few minutes max, by doing it the way I mentioned above.

Not to sure what would happen if another light was left on before powering down. If say it was a hall / landing light then I would make sure the 2 ways were off before powering down - or am I not in the right area?