Outside Light Shorting Problem

[Martin Noakes]

Everything was working fine until I decided to change the outside lamps to LED low energy bulbs.

The circuit is on its own contact breaker which goes to a timer (Time-guard TS900B). The timer stopped going round but I could use the manual on off to operate the lights.

I replaced the timer with an identical unit which worked for a couple of days and then the contact breaker flipped, and I can no longer re-set it.

With the consumer unit on - ALL of the cables are shorting out except for the Brown Live cable

With the consumer unit turned off The Black Grey and Blue still short but the Earth doesn't.

Any suggestions as to where the problem may be?

Many thanks for any suggestions

Martin

There is a 5 core cable to the timer - Brown, Blue and Green/Yellow (Supply) and a Grey and a Black cable see video here -

https://www.youtube.com/embed/lm_V5pl3WJ4?feature=oembed

 

[Lurch]

It would help if we knew what the cable cores functions are, and earthing type, and what exactly you are thinking you are testing. Are you randomly prodding your meter into random terminals and expecting to see something, or not see something?

 

[SPECIAL LOCATION]

The phrase 'shorting' is meaningless in this case..

1/ what scale was your meter on?

2/ what readings are you actually getting.

3/ where does the other end of the cable go to.

4/ you will almost certainly get some sort of continuity between various conductors with an RCD in the circuit.

5/ are you aware that Earth and Neutral are joined at the suppliers source.?

6/ I would guess the Black and Grey are you just reading a continuity though the lamp... which you need or the lamp wont work.

7/ What voltages are where ..

8/ Which terminals did you join your wires up to in the TS900B

need more info...

 

[kerching]

Have you

removed lamps

disconnected timer

otherwise you will get a circuit through the lamps ( or may only get it in one direction if there is a diode blocking it) and a circuit possibly through the timer motor and/or  timer contacts....along with what @SPECIAL LOCATION said about the neutral

 

[Martin Noakes]

The phrase 'shorting' is meaningless in this case..

1/ what scale was your meter on?

2/ what readings are you actually getting.

3/ where does the other end of the cable go to.

4/ you will almost certainly get some sort of continuity between various conductors with an RCD in the circuit.

5/ are you aware that Earth and Neutral are joined at the suppliers source.?

6/ I would guess the Black and Grey are you just reading a continuity though the lamp... which you need or the lamp wont work.

7/ What voltages are where ..

8/ Which terminals did you join your wires up to in the TS900B

need more info...

I copied the wiring from the old unit - 1=L 2=N 3=E 4=Grey (Neutral?) 5=Black (Live) - 1,2 & 3 = Supply 4 & 5 = switched output to outside lights.

I thought that someone may have had a suggestion with the info I gave. Nothing is different apart from the Low energy bulbs.

Thanks for the answer.

 

[Martin Noakes]

Have you

removed lamps

disconnected timer

otherwise you will get a circuit through the lamps ( or may only get it in one direction if there is a diode blocking it) and a circuit possibly through the timer motor and/or  timer contacts....along with what @SPECIAL LOCATION said about the neutral

I will do that now and get back

 

[Richard-the-Ninth]

I wonder if when you changed the lamps you opened the light fitting and when you closed it crushed a cable core or two..

 

[Doc Hudson]

From your Video it looks more to me as though Grey (with brown sleeve) is a switched live & Black with no sleeve  is neutral.

Doc H.

 

[Martin Noakes]

I have taken the lamps out and removed the timer. I can now reset the MCB. I'm wondering whether the new switch has also blown because of the load I had. I have put the meter across the terminals and have found the following: SL is always connected to the Live terminal whether the timer is in the on position or not. The Neutral is also permanently connected to the neutral.

I would have thought that when the switch is off the neutral and Live should NOT be connected together am I correct?

The manufacturer of the timer states - see image 2. I was using both LED and Halogen bulbs about 150W of halogen

http://www.timeguard.com/media/2721/TS900N_Instructs_100x72_issue2.pdf

 

[Lurch]

SL is always connected to the Live terminal whether the timer is in the on position or not.

Sounds faulty.

The Neutral is also permanently connected to the neutral.

Sounds correct.

I would have thought that when the switch is off the neutral and Live should NOT be connected together am I correct

Not sure what you mean here.

 

[Doc Hudson]

Have you also tested the light works manually without the timer connected? as has been suggested by Richard have you got a squashed conductor that has now shorted the supply and welded the timer contacts together. I think you need full continuity and insulation resistance tests done on the cables from the MCB to timer position and from timer position to the lamp, to verify correct polarity and nothing damaged. As an aside from the particular problem mentioned, I would suggest if you are replacing the timer again, get a modern digital one that will retain the correct time in the event of a power cut. Those mechanical ones can soon get out of synch if you have a couple of power outages.

Doc H..

 

[Martin Noakes]

Have you also tested the light works manually without the timer connected? as has been suggested by Richard have you got a squashed conductor that has now shorted the supply and welded the timer contacts together. I think you need full continuity and insulation resistance tests done on the cables from the MCB to timer position and from timer position to the lamp, to verify correct polarity and nothing damaged. As an aside from the particular problem mentioned, I would suggest if you are replacing the timer again, get a modern digital one that will retain the correct time in the event of a power cut. Those mechanical ones can soon get out of synch if you have a couple of power outages.

Doc H..

Great advice ... Many thanks