100A main breaker tripping with low loading?

[reefagrim]

first this i would do is look outside is the supply TT or TN-C/-S as for the lighting tripping a high inductive load found in fluorescents can cause tripping. Your best bet is to do a visual inspect of the enviromet that the installation is within and tell the client that you recommend a condition report be carried out. Village halls have groups of " freinds of " who carry out repairs and maintenance and on the other hand it sounds old probally still has original wiring within somewhere the possibilities are endless but the condition report will be the best option to find what your dealing with otherwise your end up being a dog chasing its tail

 

[Darkwood]

Do a full day free inspection (visual) bit of testing etc load clamping...... just to get you bearings, explain this will be free as you never know in the future when a village hall might come in handy for a family do'.

But would deffo as reef said be looking at the lighting and possibly inductive inrush.
Do a count up and size and type of lamps, i bet if inductive you can simultaneously switch all banks on at same time and get front end to trip where-as one switch at a time wont show an issue.

 

[Knobhead]

Three weeks and still no results of any testing. Do you have the necessary test kit or are you working on guesswork?
Plenty of wild guesses from all sides based on no information.

 

[MarkieSparkie]

Well said Tony! I've stayed out of this thread for exactly that reason. I'm amazed the number of recent OPs who are prepared to spend any amount of money substituting component parts to try and find a solution, but will not get the test equipment out and do even the most basic of tests. In at least one case, actively taking on work without possessing any test gear at all and did not see a reason for any. When they get into difficulties, unable to solve their problems, they start a thread on the forum and expect us to be clairvoyant. If this a representative sample of the calibre of Electrician currently coming of the production line; heaven help us all!

 

[vernam616]

Too true, amazing how people have to consult a forum to fault find, i usually just go get my test kit out because....... Im an electrician and thats what im trained to do

You should do the same OP

 

[wildgoose]

Your not going to know anything, until you get your test kit out and start going through the system. Just wondering how dedicated circuit RCD'S can trip out the whole DB?? Another reason why you don't always take notice of anyone that has unreliable knowledge of what's happening and when... At the moment no-one can advise you on what's causing the fault(s), the permutations being too many!!

Engineer54 is spot on. Until you get your test kit out and/or experience it yourself, then take what's described as 'background info only not to be relied on'. My experience of 'information via committee' has not been very reliable in the passed!