Advice regarding inrush current please?

[HappyHippyDad]

I have just fitted 5 x 200w LED floodlights on the same switch.
I fitted 3 yesterday all worked fine. However the owner said they tripped once after I had left, no further info as to if they tripped immediately or after a while.

I have just fitted the last 2, the MCB is tripping immediately when the lights are switched on.

It also trips immediately when only 4 lights are connected.

At present they are on a type B 6A MCB.

The RCD does not trip and there is no fault to earth.

I had zero time to investigate and am returning in the morning.

My thoughts are.

1. Short circuit L-N
2. In rush current.

I know LED's can have a high in rush current, but could 3x200W LED floods (power factor 0.9) cause the MCB to trip? Could 4 or 5 cause it to trip with regards in rush current?

 

[Pete999]

Well the 5 lights work fine on either a 10A Type B or a 6A Type C, so I should be ok with all 10 on a 20A Type B or possible a 10A Type C. Also the next 5 will be switched separately so that will avoid the inrush current of all 10 at the same time. Happy

Until some body switches, all of the lights on at once, you just know it's going to happen Murphy's Law dictates this.

 

[stevethesparks]

Space each switch 3ft apart, this will give the desired time delay

 

[Andrew B]

You can find the time Vs current curves for type b,c,d MCB in the installation and test regulations.
Type B instantaneous trip is 3-5 times rating
Type C instantaneous trip is 5-10 times rating
Type D instantaneous trip is 10-20 times rating

This is the magnetic trip and applies to inrush current.

I should add that the current is RMS current, so averaged over 1 half cycle. So very high inrush currents lasting less than half a cycle might not trip the MCB if the average over that cycle is lower than the trip characteristics.