LED lighting circuits Breaker type

Stoner

Has anyone notice an increase in the amount of LED strip fittings tripping type B and even Type C MCBs.

We've seen it on a couple of jobs where after a period of time (not on initial inrush current) the MCBs are tripping.

Have you guys seen this, these are not cheap fitting either,



Type B devices are designed to trip at fault currents of 3-5 times rated current
Type C devices are designed to trip at 5-10 times
Type D devices are designed to trip at 10-20 times

The loop impedance test would need to be carried out again when moving from B to C to D

Sir Arthur Daley

What is the prognosis on the tripping, overload or short circuiting? Often good products have their flaws.

adrian92

Possibly due to the presence of harmonic currents . I am speculating - I do not even know if MCBs only sensitive to 50 Hz. Just a thought.

mikeyjames9

adrian92 wrote: »

Possibly due to the presence of harmonic currents . I am speculating - I do not even know if MCBs only sensitive to 50 Hz. Just a thought.

i think mcbs are sensitive to harmonic currents

I've run them on DC MCB's to the driver, no transformer, no problem.

mikeyjames9

Sir Liamalot wrote: »

I've run them on DC MCB's to the driver, no transformer, no problem.

aren't the drivers fed from the mains?
http://www.meteorelectrical.com/36w-driver-for-led-under-cabinet-strip-light.html

where does the DC mcb fit into that scenario?

That's a power supply not a driver, the driver is the PWM dimming unit.



Mine are 12VDC-24VDC. I don't have mains. So Batteries -> DC MCB -> driver -> strip lights.

The usual setup is Mains -> MCB-> AC-DC 12V/24V switch mode power supply -> driver -> strip lights.

Then they've isolated data control for colour mixing.

mikeyjames9

no bother

i thought they would be all one


electronic power supply and driver

2011

adrian92 wrote: »

Possibly due to the presence of harmonic currents

Yes, I was thinking this myself.
Harmonics distortion can be caused by nonlinear loads such as VSDs or UPS.
I rang Stoner & suggested this to him, but he explained that these types of loads are not present in this installation.
We both concluded that this issue is most likely the LED driver.

A bit of Goggling and I found the following:

Issues caused by harmonic distortion include:
● Erratic operation of breakers and relays.
● Overheating in neutral conductors, transformers and motors.
● Deterioration or failure of power factor correction capacitors.
● Pronounced magnetic fields local to transformers and switchgear.
● Problems with microprocessor-based equipment.

I saw a power factor correction (PFC) unit go on fire in a plant recently because multiple DOL motors (over time) were replaced with VSD fed motors. The VSDs caused harmonic issues which in turn caused the PFC to overheat. We had to replace the burnt out unit with a new "detuned" version. These are designed specifically to work with nonlinear loads.

Mr Magnolia

2011 wrote: »

I saw a power factor correction (PFC) unit go on fire in a plant recently because multiple DOL motors (over time) were replaced with VSD fed motors. The VSDs caused harmonic issues which in turn caused the PFC to overheat. We had to replace the burnt out unit with a new "detuned" version. These are designed specifically to work with nonlinear loads.

I've heard of this happen myself. What brand of VSD were they?

2011

Mr Magnolia wrote: »

I've heard of this happen myself. What brand of VSD were they?

Mainly ABB but also some older Loher units.
In addition there are a lot of UPS.

maxamillius

That's interesting,we have 2 Pfc units in our building one of such went on fire a month ago,capacitor blew in it!we had about 10 vsds installed in the building last year for the ahu's,wonder did that have an effect?or is a year to long to keep it as a valid reason?

Stoner

we are going to plot the load over a few days, I'll get back with the results, overall we are not happy with the response the suppliers have been giving us on it, very wishy washy.