Discuss Mcb tripping on led lights in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

cliffed

-
Arms
Reaction score
644
Finished a refit of 7 x 200watt led lights to existing circuit.
The orignal circuit had 120 watts per light,so 140 watts x 7...say 1kw.
These are 1.4 kw,so not really loading the circuit.
There are other lights on the circuit,it’s a 10amp b type MCb.protecting it.
The lights are working, & suddenly without any reasoning mcb trips,they can be on all day,& never tripped when switching on off,over several days.
But will trip randomly.
Any ideas,I’ve switched they repeatly on off to see if I can trip the mcb,but never trips on that.
 
could be in rush current?
The rated wattage/lumens in itself isnt the issue its the inrush draw of the transformers. can be several times the actual rating of the light. some fittings are worse for it than others.
I had it recently, according to the lighting design people who specified the job the 10 high bay led fittings at 8500 lumens each (all these in the warehouse would have been on a 10A Type B) the design people specified a type b and had same problem as you.
Tripped randomly when turned on.
Swapped for a Type C 10A and all hanky dory as they say.

you should also check the light data sheet, some led fittings are very poor quality and use cheap chinese crap inside, some transformers are just current drains and get hot. likewise not all leds are equal.
 
If tripping on switch-on then inrush is the obvious answer.

If tripping at odd time is could be a very poor power factor so the RMS current is well above the stated power level. If you have access to a clamp ammeter that has true RMS (or similar) characteristics you could measure what is actually being taken.

Final thing is a bad connection really causing a fault current, so taking L+N together and testing insulation to E might show something.
 
The OP says they trip after being on for a period of time so it can't be inrush at switch on.

As per Pc1966 it could be poor power factor leading to overloads.

Or there may be supply voltage fluctuations causing the LED drivers to suddenly draw more current as they try to maintain constant power output.
 
Are all the lights on this circuit on one switch?

If they are on multiple switches then they may never all come on together and challenge the MCB.

If there is a blip that cuts power for a fraction of a second they then all come on at once and inrush may come in to play.


In truth, I stopped reading half way through the OP and just plumped for inrush.
 

Reply to Mcb tripping on led lights in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock