Outdoor Circuit has got me miffed

[Ross A]

Wonder if someone can help. I have an outdoor light circuit, with 14 lights in series. The first 3 in the series work perfectly and so do the last 4. But the 7 in the middle, flash (pulse) and then almost dim down. If it was a loose connection, the last 4 would do the same. This has got me miffed - any ideas?

Also, they are switched on by two motion sensors which are at the beginning of the circuit. 

 

[Murdoch]

What type of lights are they?

have they ever worked properly?

 

[Ross A]

Yes they all worked properly. They are TLC inbuilt Brick Lights. 

 

[Murdoch]

Who installed them? 
 

sounds to me like they aren’t all in 1 string given what you describe, maybe a junction somewhere?

 

[SPECIAL LOCATION]

Wonder if someone can help. I have an outdoor light circuit, with 14 lights in series. The first 3 in the series work perfectly and so do the last 4. But the 7 in the middle, flash (pulse) and then almost dim down. If it was a loose connection, the last 4 would do the same. This has got me miffed - any ideas?

Also, they are switched on by two motion sensors which are at the beginning of the circuit. 

Hello Ross, welcome to the forum...

Initial thoughts, I doubt they are wired in series?

You don't say what the physical cable lengths are?

But its quite possible they are split across a pair of supply cables..

Don't rule out a loose connection unless you have actually retested the cables...

Basic rule of fault finding is,  "Assume everything is faulty until you have proved otherwise"

Assuming things you haven't proved with appropriate test gear will often lead you to wrong conclusions.

Guinness         

 

[Ross A]

Definitely in series as I worked with builder and electrician to install. Have even changed some lights just in case one light was pulling them down. Only other thing to note - four lights at the beginning have T on them from main cable route builder has to move lights. The first three work perfectly and the last one is where the trouble starts. I have disconnected this light to see if that was pulling down the circuit..

 

[kerching]

Slightly curious, but, what do you mean by 'series'?

one after another in a string?

all back to one point?

all on one cable?

if so then none of these physical parameters will confirm 'series'

series ( to an Electrician ) means that one lamp derives its current through the previous fitting....so a 'chain' instead of a pair "of tram lines" where the failure of one lamp will not kill the whole string ( think old style Xmas tree lights)

i think that that makes sense ??

 

[Ross A]

Yes all on one string, on cable in/out in each fitting

 

[boltonsparky]

Do they all flash and dim together at exactly the same rate? What you are describing sounds exactly like an LED lamp failure but not if they are all flashing/dimming simultaneously which would suggest something supply side. 

 

[Ross A]

Yes - all at the same time... what baffles me is the last 4 work perfectly in the string. I could understand if they all did not work from a point.. as that would be a connection. 

 

[Murdoch]

Yes - all at the same time... what baffles me is the last 4 work perfectly in the string. I could understand if they all did not work from a point.. as that would be a connection. 

Thing is, unless you actually did the install hands on do you really know there isn't a joint some where

I would take one of the "broken" units out of the wall and disconnect it - then see whats still on - remember to isolate the circuit before you start fiddling and make the ends safe (but not joined together)

 

[Ross A]

Hi - i did put the cables in with the builder... i know there is a connection in a brick wall I cannot get too, so will try and bypass that and see if it fixes the problem. Thanks

 

[Murdoch]

Hi - i did put the cables in with the builder... i know there is a connection in a brick wall I cannot get too, so will try and bypass that and see if it fixes the problem. Thanks

top tip - NEVER make any connection unaccessible UNLESS its a joint box designed for the job. AND never trust a builder to do any sparking

Are you a DIYer?

BTW why 2 x PIRs at the start of the circuit?

 

[SPECIAL LOCATION]

Yes all on one string, on cable in/out in each fitting

They may be all one string but if they require 230/240v to each light they will be wired in parallel not series,

otherwise you would only be getting around 16volts at each light..  (e.g. 230v/14lights = 16.5v)..

I think you need to do some comprehensive dead test..

e.g. continuity & insulation resistance tests up the length of the circuit to every lamp position to check out all terminations & joints..

Randomly swapping/bypassing bits and testing live, stands a big chance of assuming wrong conclusions.

As Murdoch said..

99.9999999% of builders are rubbish at doing anything electrical..

(They are good at sticking bricks together and nailing wooden bits together!!)

even though..

99.999999% of builders will claim to be able to "Do the electrics for you"..

I am sure many of us on here could tell numerous stories of having to put right..

builders wiring..  that either never worked right..   or failed prematurely after the builder has left with his cash in his back pocket!!

Damp getting into circuits at one, (or more), poor terminations can cause all sorts of strange symptoms..

Are these brick-lights traditional type lamp fittings, (e.g. Screw thread lamp), or integral LED units with built in drivers?

Damp getting into LED fittings themselves can also cause weird effects!!

If they have LED fronts that are removable can some of the "faulty" items be swapped with some of the "good" items,

to see if the fault stays with the light location or moves with the LED / driver combination?

:coffee