Led floodlights tripping but dead tests clear...

[Adamsparks]

Hi, just finished a job installing 12no 100w led floods from ansell lighting and they are causing me problems. The lights are switched alternate over two switches, so one switch does 6 and so does the second. First of all I has them connected to a B10 crabtree loadstar mcb which tripped 9/10 times when switching on either switch line. Strange I thought, spoke to ansell lighting and they confirmed I needed a c type mcb. Great I thought, ordered a C10 and all my lights fired up no problem. Customer was happy and so was I. Had a phone call two days later, lights have tripped. Why is this? I can't find any power factor for these lights, so therefore can't work out the peak load upon start up. It's wired in 1.5 and has a zs of 1.82 end of line so can't go to a D type . Any suggestions? Can't go any further on the breaker size, and it's roughly a 70m run. Have thought of putting the circuit through a spur on a B16 breaker and leaving it with the 13a fuse to see if this gives it the leeway it needs....

 

[iamelectric]

had the same problem had to upgrade the mcb to a 32amp lucky we wired them in 6mm , i read another thread says the start up is enormous on led floodlights

 

[GLENNSPARK]

Hi, just finished a job installing 12no 100w led floods from ansell lighting and they are causing me problems. The lights are switched alternate over two switches, so one switch does 6 and so does the second. First of all I has them connected to a B10 crabtree loadstar mcb which tripped 9/10 times when switching on either switch line. Strange I thought, spoke to ansell lighting and they confirmed I needed a c type mcb. Great I thought, ordered a C10 and all my lights fired up no problem. Customer was happy and so was I. Had a phone call two days later, lights have tripped. Why is this? I can't find any power factor for these lights, so therefore can't work out the peak load upon start up. It's wired in 1.5 and has a zs of 1.82 end of line so can't go to a D type . Any suggestions? Can't go any further on the breaker size, and it's roughly a 70m run. Have thought of putting the circuit through a spur on a B16 breaker and leaving it with the 13a fuse to see if this gives it the leeway it needs....

pull in a seperate 4mm G/Y...then go for a D curve..

 

[Adamsparks]

Hmm not that simple, it's all run about 7meters up round the perimeter of the inside of a church which was done off of a scaffold tower. Not my choice of lighting I might add, just doing what i was told but going there tomorrow to attempt a solution.

 

[GLENNSPARK]

Hmm not that simple, it's all run about 7meters up round the perimeter of the inside of a church which was done off of a scaffold tower. Not my choice of lighting I might add, just doing what i was told but going there tomorrow to attempt a solution.

well...i`v given you a solution...
so it may be an exercise with the ladders....
but you will either have to replace the cable feeding these (more costly)....
or go for the parrallel path...as i have suggested at #3

 

[Adamsparks]

Yeah your right, my superior is adamant it's a fault on my behalf despite my many attempts of tying to explain high start up currents, I'll get the ladders from the yard in the morning but will keep and open mind until then. Thanks Glenn

 

[jackhammerJIM]

can you get a new supply to the switch and split across 2 circuits ?

have you measured the startup current ?

 

[Adamsparks]

Switches are right next to the board, but goes off in a 4 core using the brown and black as the switch lines as the cable goes past each flood light, ie lights 1,3,5,7,9,11 are switched from the brown and 2,4,6,8,10,12 switched from the black, sharing the same neutral and g/y. No haven't measured yet was going to do first thing tomorrow. Admittedly when I fitted the C10 I switched the switches separately meaning only 6 peaked at once instead of all twelve, I'm thinking maybe the vicar has pressed in both switches at once...

 

[Lucien Nunes]

Lucien's Heath-Robinson idea of the day (I have a lot of them!):
On-delay timer in one switch line to defeat the slick-switching vicar.

 

[GLENNSPARK]

Yeah your right, my superior is adamant it's a fault on my behalf despite my many attempts of tying to explain high start up currents, I'll get the ladders from the yard in the morning but will keep and open mind until then. Thanks Glenn

well...as you have been advised...its startup currents...so your `boss`..whoever he is..is speaking botty talk..

but never mind...

look, several suggestions here...split the load or pull in a parrallel path...

there is a third however...:
make em a ring...

 

[GLENNSPARK]

Lucien's Heath-Robinson idea of the day (I have a lot of them!):
On-delay timer in one switch line to defeat the slick-switching vicar.

and how refreshing not to hear of `magic` RCDs being employed to get around dodgy Zs..

as yet..

 

[Lucien Nunes]

Also, looks like you're just in for a K10 MCB (8-12xIn) on the existing cable, which gives you just a little more elbow-room and more tightly controlled instant-trip characteristics.

 

[Adamsparks]

Just looking at the on delay switches now. Please
elaborate on your above post regarding the k10 mcb

 

[Darkwood]

The inrush current of LED luminaires is determined by the driver(s). This can be as high as 400 times the running current for a fraction of a second. This inrush duration is significantly less than the 10ms lower limit for conventional MCB tripping. However, some MCBs have a second tripping functionality, for inrush durations less than 10ms, having an increasing tolerance to high inrush currents related to the logarithmic inverse of the duration.

Basically when designing circuits with switched inductive loads especially multiple you need to engage with tech' of the MCB manufacturers giving them the inrush details of the LED driver and number per circuit your switching or you end up in the situe you found yourself in, i suggest your boss goes on a design course for Electrical systems bigger than domestic if he is incapable of correctly instructing/guiding you of the correct methods to apply in design rather than blindly blame you.... if you yourself haven't done further education regarding in ciruit design then it may be food for thought if you do this can of install often.

This is on the assumption it is the highly likely inrush issue and not a faulty driver etc.