Rcd on car park lights.

[highspark]

Continued from thread yesterday. Regarding timer and photocell.

Customer rang me this morning and said rcd had tripped again.

Now this is a bummer to me at the moment because my fluke has been in for calibration since Wednesday. So no meter at the moment. Arrgh

Anyway when I went to have a look yesterday there was no tripping at all. Even when I covered photocell. I had no tripping and left assuming that when it went dark all lights would operate how they had when photocell was covered.

I can give everyone a fair idea of the installation.

On the front of the car park there is 4 floodlights with SON lamps. Further to those is the photocell sensor and further to those at back of the building is 3 security lights on PIR sensors. Aswell as 4 normal outdoor fittings above each patio. They are all on the same circuit.

My first thoughts are that one of the PIR lights may have water ingress and at night once picking up motion it trips the RCD. I think this because yesterday all lights worked fine once photocell was covered. Except PIR lights as their sensors where not covered!

Any thoughts. Bad timing to not have the fluke!

 

[telectrix]

think you may be on the right track. can you borrow a megger while your fluke is away?

 

[highspark]

Not between now and Monday! I have an old fluke that my ex smashned the screen in sitting in front of me haha how ironic! Just hope meter is back early Monday!

 

[highspark]

Update: I've been around PIR sensors and found moisture in security light so removed load from circuit.

I have now witnessed the RCD tripping. (wasn't happening on friday and with moisture ridden security light gone)

The board is a small hager 4 way. Tails straight from meter into rcd acting as main switch supplying hallway sockets, hallway lights and car park lights.

The RCd trips and won't reset when car park lights are switched on. When I isolate car park lights mcb it still trips.

When I isolate hallway lights and car park lights at the same time rcd resets and when I flick up hallway mcn the lights and rcd stay on???

I still haven't got my fluke but I'm thinking dodgy rcd here?

 

[Mark_Burgess]

Maybe one of the enthusiastic willing to learn fault finding persons on here, could meet up with you (and bring their tester) for a learning exercise?
Put an add in the job section!

 

[highspark]

A soon as earth is removed from Earth bar of car park lights no tripping. As soon as it touches TRIP!

 

[markthespark]

Could it be a neutral to earth fault on the PIR floodlight circuit where the moisture is getting in, i know you said you removed the load from the circuit but have you disconnected it completely from the circuit? ie L, N & E and see if it still trips the RCD.

**apologies** just read further down.

When I isolate hallway lights and car park lights at the same time rcd resets and when I flick up hallway mcn the lights and rcd stay on???

Have you tried to disconnect the hallway lights from the consumer unit completely and turn the car park lights on and see if it still trips then? That way you can rule out any problems with the car park lights and concentrate on the hallway light fault and vice versa if it still trips.

 

[highspark]

Security light has been completely removed. I have now split the circuit in half and still tripping. The only things left on the circuit are 4 car park floodlights and the photocell.

 

[sedgy34]

just a thought here! eliminate the photocell and link it through ive had dodgy photocells in the past

 

[highspark]

The photocell has no earth going to it and its and it's an earth fault

 

[Guest111]

The photocell has no earth going to it and its and it's an earth fault

where are you?

 

[highspark]

Last two floodlights: one is absolutely full to the brim of water. Covering connector block inside. Literally a glass full. But light is still working! Lol

Final floodlight disconnected earth no trip. Connected earth back up TRIP. Disconnected no trip. Connected one more time for piece of mind TRIP.

Think I got the bugger earth fault on floodlight. Intermittent though! Two new flood lights it is.

 

[Richard Burns]

Have you got a crossover somewhere between the hall way lights and the car park lights on L or N?
If the fault requires 2 MCBS to be off to reset it makes me think there may be a borrowed neutral somewhere, just a thought.

Too slow typing, ignore me water in fitting, good luck.

 

[londonlec]

You shouldnt disconnect earths even in supervised testing conditions. Use your meter on IR between L + N to CPC.

 

[highspark]

Read thread! I had no meter. Only way to do it. Also only removed earth at the end of line - loads (floodlight)earth.

I'm all for by the book but London you are far too pedantic