LED Floodlight

[carl9254]

Hello.

Just a quick question.

Got 8 140w led floodlights running on a B20 mcb. The lights come on through a mechanical timer but the customer says everytime the timer switches it trips the mcb. But they work fine when the manual switch on the timer is pressed. Can you run LEDs of a manual timer?

Thank you.

 

[telectrix]

try a C16 or a C20 curve MCB assuming the Zs complies.

 

[carl9254]

Do they have much surge though?

 

[telectrix]

LEDs do and the timer might just be the last straw.

 

[Darkwood]

They are inductive loads all the calcs etc and switching ability including the rating and type of mcb needs calculating with respect to their combined inrush spike....

The mcb is a B type and even though 20amp the time curve is probably your issue to nuisance tripping... i would speculate this has been installed by a domestic sparkie who hasn't done further education with regards to circuit design courses.

My first port of call would be to ring the manufacturers and ask about the peak inrush for 1 fitting then liaise with the mcb's manufacturers with this info and see what max nno' fittings can be put on any one mcb.. once you know this then you design the circuit to eliminate nuisance tripping on inrush.


To give you an idea if this is the issue disconnect half the fittings and try again and also try a C and D type to see if this also stops the tripping if so you need to redesign the circuit if you can't meet Zs values with a C/D trip curve.

 

[Tridentsystems]

^^^ Quite. I had it with some Phillips fitting 75 A inrush. Only for mS but needed C types

 

[electrician4u]

Hello.

Just a quick question.

Got 8 140w led floodlights running on a B20 mcb. The lights come on through a mechanical timer but the customer says everytime the timer switches it trips the mcb. But they work fine when the manual switch on the timer is pressed. Can you run LEDs of a manual timer?

Thank you.

sounds like a faulty timer as the manual switch will create the same surge, assuming there is one, as the timer switch

 

[Darkwood]

From what you describe it sounds like a Sangamo timer and only has a clock motor as all switching etc including the over-ride is purely mechanical action, the timer funtion may be closing the contact at a slower rate than the quick snap action of the over-ride button and may create additional spike inrush as if an arc is created due to slower switching.... it would still point to the size of inrush been a key factor... can you confirm the make of time clock?