Led street lights tripping mcb

[cliffed]

Just had a quick look at a job,intermittent tripping of 10 amp mcb,retrofit led replacing discharge lighting,some time ago.
There are 7 street lights,couldn’t real do too much investigation,rain stopped play.
Did a IR test proved to be satisfactory,just wondering if any of you guys
Had any thoughts.

 

[SparkyChick]

I suspect it's in-rush current from the drivers in the LEDs. If Zs is OK, you may be able to change the MCB to a Type C which may be able to handle it.

 

[cliffed]

Yea thinking that too,not too much information on wattage,but the other lamp posts another 7 are exactly the same & pose no problems.

 

[Octopus]

Do dead tests to confirm suitability of changing the breaker .........

people don't consider this when changing to LED's

 

[SparkyChick]

The fact one breaker works fine and another doesn't, could be manufacturing tolerances, age, manufacturer... the other may even already be a Type C.

 

[cliffed]

Do dead tests to confirm suitability of changing the breaker .........

people don't consider this when changing to LED's

Agree,this problem just happening after approximately 6 months,seems a bit weird

 

[ipf]

I suspect it's in-rush current from the drivers in the LEDs. If Zs is OK, you may be able to change the MCB to a Type C which may be able to handle it.

Good chance.....but 'some time ago' may have some bearing.
Presumably it's been OK for that long.

 

[ruston]

Just had a quick look at a job,intermittent tripping of 10 amp mcb,retrofit led replacing discharge lighting,some time ago.
There are 7 street lights,couldn’t real do too much investigation,rain stopped play.
Did a IR test proved to be satisfactory,just wondering if any of you guys
Had any thoughts.

Water maybe , depending maybe if they are linked?

 

[cliffed]

Water maybe , depending maybe if they are linked?

Will check ,but IR seems ok 2.5 M ohms.

 

[Octopus]

If the MCB can be changed and the IR is good - I would do that first....

More info needed really.

 

[ruston]

Will check ,but IR seems ok 2.5 M ohms.

I have had this before when the accumulated puddle got deep enough to short it out.

 

[cliffed]

Cheers to all...thanks

 

[markc123]

Could literally be something as simple as a knackered MCB.

Any pattern to the tripping? Or just random?

Inrush, Water, MCB.

What’s the location of this? I once had a mystery street light tripping on a Caravan Park. Turned out to be Mr.Smith turning it off himself as it was disturbing his sleep been located straight outside his bedroom window.

 

[cliffed]

It’s been monitored by local council,there’s no set pattern,but once a week apparently.
Thinking in rush,but there are other lights exactly the same,these are ok.

 

[SparkyChick]

Just a couple of thoughts I've had about this...

As I understand it, in-rush is it's cycle dependent.

If by chance the lights are turned on at exactly the peak of the cycle, the in-rush current is likely to be huge due to the large potential difference, where as if the lights are turned on at the zero crossing point, the in-rush will be practically non-existent as the potential difference that drives the current will be zero.

If they are contactor controlled, could it be a result of intermittent contact bounce? If the contacts don't settle quickly you could be getting a few spikes in current consumption which may be enough to push the MCB over the edge.