# Interest group forums > Electrical Contracting Industry Forum >  Random earth leakage problem

## BillH

For a few months now I have been experiencing random earth leakage problems - earth leakage switch tripping for no apparent reason. For a while it appeared to be both random trips and when plugging in a charger power brick for a laptop. 

I have now spent several thousand rands on replacing all sorts of things based on advice from sparkles, eg gate motor, pool pump, all day/night switches, plus I have had the garage/workshop rewired with a new DB and own earth leakage breaker because some of the problems occurred when the garage lights were switched on each day! Each of these faults was detected using a 'megger' (?). 

Interestingly I find that this still occurs BUT still trips in the house and not at the new EL breaker, despite all the feed from the house now via the new switch.

I cannot find a sparky who can get me past this point.

I understand that the combined effect of power bricks and ups units (I have several ups units powering essential systems in the office) can create a background earth leakage level that makes the el breaker trip at very low additional el loads?  

I would appreciate some diagnostic advice as this is now driving me nuts!

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## murdock

if it is a heineman  60 amp unit dated 2006 - 2008 i can understand...i have been having huge problems with heinemen 60 amp earth leakage units...to a point  that i now longer install heineman earth leakage units....and the joke..heineman only offer a 1 year warranty...i wonder why.

i had a simmilar problem in december...i managed to find the problem...a wire which was no longer used...but not diconnected...i managed to find all the other little issues in the house...like water in light fittings...gate motor and pool pump...must have been from all the rain we had...once all the little faults whre found...the earth leakage unit still tripped...i replaced the earth leakage unit with a different make and havent had a call sinc...i did test the new earth leakage unit with an earth leakage tester and it did trip at 25 mA

an insulation resistance tester(commonly refered to as a "megger" which is a brand of insulation resitance testers ) is used to find insulation resistance issues...

fluorescent light fittings are a common problem when connected to an earth leakage units...when they ignite (start up) they cause tripping issues...bad idea to have them connected to an earth leakage unit...but in saying that...all sabs regs must be adhered to at all times.


sounds to me like the sparky has connected the new earth leakage in series...which is incorrect...it must be connected in parallel...believe it or not but this is a common practice...a quick way to determine whether the sparky knows what he is doing or not...

i sympathise with you trying to find a good sparky...there are hundreds if not thousands of them out there but when it comes to anything more than chasing walls and connecting plugs...there are only a few good ones left.

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## Dave A

Has the earth leakage unit in the house been replaced?

Nuisance earth leakage tripping sure is a PITA. Part of the problem is the fault that is causing the tripping never gets enough juice to really advertise where it is while on the earth leakage unit. My sparkies use the term "blow the fault clear." It involves taking the suspect circuits off earth leakage so that when the fault blows, it blows properly!

Obviously needs to be done with due regard for safety issues, and I'm probably going to take some flack for even suggesting it - but sometimes it is the only way to find the fault.

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## AndyD

> For a few months now I have been experiencing random earth leakage problems - earth leakage switch tripping for no apparent reason. For a while it appeared to be both random trips and when plugging in a charger power brick for a laptop.


There's no reason a laptop power supply would cause earth leakage, they're usually Class II appliances and don't even have an earth connection. 




> I have now spent several thousand rands on replacing all sorts of things based on advice from sparkles, eg gate motor, pool pump, all day/night switches, plus I have had the garage/workshop rewired with a new DB and own earth leakage breaker because some of the problems occurred when the garage lights were switched on each day! Each of these faults was detected using a 'megger' (?).


Assuming the electrician removed the garage subDB from the RCD (earth leakage breaker) in the house when he fitted a new RCD in the subDB then this rules out the garage as being the problem. If the garage is still supplied via the main RCD in the house then without discrimination it's a lottery which one would trip fiirst to a fault in the garage. 




> I cannot find a sparky who can get me past this point.


This seems to be your problem. You need someone who's capable of localising and fixing this problem. You're going to have to get past the cheapest price mentality and find a good capable electrician and pay him his extortionate labour rate to find the problem. 




> I understand that the combined effect of power bricks and ups units (I have several ups units powering essential systems in the office) can create a background earth leakage level that makes the el breaker trip at very low additional el loads?


 Firstly there's no such thing as background earth leakage. There's just earth leakage.... period. Earth leakage is usually measured in milliamps unless there's a lot of it and then it might be measured in amps.

Secondly class2 appliances (double insulated) such as cellphone and laptop chargers would have zero earth leakage. A UPS usually has a chassis with an earth so with the UPS it's possible to have a low insulation problem resulting in earth leakage. It is unlikely however and would easily be proved using a Mega tester. 




> I would appreciate some diagnostic advice as this is now driving me nuts!


 My immediate diagnosis is that you need a decent electrician otherwise your prognosis is looking bleak.

RCD nuisance tripping is one of the more difficult problems to solve. 
Start with sorting out the easy stuff and only then get complicated if necessary. 
1  Ramp test both RCD devices.
2  IR test all circuits on the main DB and fix anything with an IR value of less than 2 MΩ.
3  Do same with Sub DB in garage.
4  Check both DB's for circuits with borrowed or crossed neutrals. 

One thing you can do is keep a log of every time the RCD trips. Note the time of day, exactly what appliances are running and any other circuit breakers that trip at the same time. 

Can you attach photos of the inside of the main and garage DB's?
Can you tell us whether the RCD resets first time after it trips?
The more info you can give the better.






> fluorescent light fittings are a common problem when connected to an earth leakage units...when they ignite (start up) they cause tripping issues...


If fluorescent light have low IR readings then they're faulty. A fluorescent light should present no earth leakage even during ignition cycle.




> My sparkies use the term "blow the fault clear." It involves taking the suspect circuits off earth leakage so that when the fault blows, it blows properly!


 Not sure what 'blow the fault clear' means but the phrase is exciting in a very scary sort of way.

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## BillH

Thanks very much for your response. I can respond to the issues you raise as follows:

The earth leakage switches are both Heineman but I have no idea as yet re their manufacturing date. Will look tomorrow. I was not aware that there are other makes? Can you recommend what I should buy?

The fluorescent lights did not trip today - first time for a while after the sparky said he found loose connections in the switch yesterday.

The only trip I have had today was when I plugged one of my microscopes (I am a biologist) into a multi-plug.  Not sure how this could happen as this only powers the lamp and it's a new scope.

Multiplugs are so necessary but seemingly problematical.  Is it possible to buy good quality multiplugs that have an in-built trip switch?

The sparky did not disconnect the sub-board feed from the trip switch in the house.  I assume this is what you mean by in series?  I did ask him why I assumed he would have by-passed the house trip.  He indicated that this was how it should be done.

I would really like to find a knowledgeable electrician.  The guy I am using now was recommended by Geyserwise, before that I was using a "reputed" Somerset west company who eventually just stopped coming back.  They have not been cheap either, plus they have recommended a lot of expensive replacements of stuff that turned out to have not been the problem.

I am open to any recommendations for a good sparky in the cape town area - or an electrical engineer who does fault finding!

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## BillH

Yes, it was replaced quite early in the process.

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## BillH

Thanks for your time to respond so comprehensively.

I found a USA forum where someone found that different laptop power bricks tripped his circuits from different points in his house.  This is exactly what I have been experiencing.  The forum responder said that this was common and that with many such units plugged in renders the earth leakage more sensitive.  Seemed logical at the time - some transformers give quite a buzz if you touch the wall socket end when disconnecting?

I urgently need to find a good electrician who can fault-find in a scientific manner?

We have kept logs for a while but could not link the faults to any appliance switching on or off.  We have three types of occurrence: entirely random, plugging in a charger or the garage light issue.  The random could be ants or geckos but we cannot find where if this is the case.  Maybe a frayed wire underground somewhere.

Thanks again!

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## BillH

I forgot to add that the earth leakage resets immediately.

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## BillH

Hi again,

In response to the make of earth leakage switch, they are not Heineman (my mistake) but are marked "CBi".  Most of the other breakers on the boards are SAMITE, with one or two Heineman switches left over from the original DB when we built the house 30 years ago.

Is the CBi make OK?

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## BillH

Ok, today (Friday), had a random trip around 08:00 and the garage lights again tripped the house RCD and not the new one in the garage!

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## garthu

You gonna have your hands full with this one...I'm not a pro on this so leave it to the likes of AndyD/Dave etc but wanted to chuck this in anyway as have had a load with it with the rains. Related to water anyway? Rain, sprinklers, bath emptied. Sure you considered it but just offering.

AndyD... love the comment.. 


> Not sure what 'blow the fault clear' means but the phrase is exciting in a very scary sort of way.


It does hey! Need to be around to see this one... kinda like an exciting Guy Fawkes eve  :Smile:

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## Sparks

You bet it can be scary. Too many youngsters here for me to suggest it but now the cat is out the bag. I just hope they are at least carefull when trying it. I have read this thread from the beginning and it appears all the bases have been covered. In light of the fact that the power tripped with the 'scope I suspect it could be a "imported" multiplug. The finest quality I love as much as a bicycle pedal. I am however also considering the scope itself does it perhaps have a transformer and then finally, is there perhaps a incorrectly installed SPD? As for CBI, they are all I use.
As was mentioned, the best for you here is to note what is plugged in at the time of tripping. 
In closing, do not throw the geyser out before checking. Some idiots actually do wire them through the ELCB

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## Dave A

> AndyD... love the comment.. 
> 
> 
> 
> 
> 			
> 				Not sure what 'blow the fault clear' means but the phrase is exciting in a very scary sort of way.
> 			
> 		
> ...


Probably sounds more dramatic than it is - certainly not Guy Fawkes level. What you're trying to achieve is a fault current limited by the over-current protection rather than the piddling 30 mA or so you get on earth leakage protection. It makes the flash-over point easier to identify (especially in the dark), or permanent (carbon tracked or fused).

We normally go this way when we've identified an underground cable fault, but the client doesn't want to run to the cost of a thumper test or replacement of the cable without clear, unarguable evidence - and they're not happy with a marginal insulation result using a meggar. Take the cable off earth leakage, put earth leakage protection on the demand end, and with the next rain the fault really blows.

However, we did have one where we'd pinned the problem down to a lighting circuit. It turned out the surfex cabling had a series of tiny pin holes in it - literally only visible with a magnifying glass - and I doubt we would have found exactly what the problem was any other way than watch for the flash.

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## BillH

OK, sparky came back today to connect the new RCD in parallel, but this was a miserable failure as he could not get it right and ended up with everything tripping.  We are now back where we started with a new RCD that doesnt do anything?

Anyone know of an electrician who knows what they are doing??

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## AndyD

I've come across those damn 5 into 1 multi-plug adapters where the indicator neons in the switches were wired between the switched live coming off the switch and the earth. Each multiplug showed about 2.5 MΩ @ 500volts test and three of them was enough to cause nuisance tripping. 

The thing with earth leakage is that unless the circuits are all on individual RCBO's it's a cumulative fault so a lot of small IR problems dotted around an installation all mount up to appear as one big problem at the single RCD.

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Dave A (06-Jan-12)

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## AndyD

> OK, sparky came back today to connect the new RCD in parallel, but this was a miserable failure as he could not get it right and ended up with everything tripping.  We are now back where we started with a new RCD that doesnt do anything?
> 
> Anyone know of an electrician who knows what they are doing??


I love a good fault that you can get your teeth into but unfortunately I'm flying out again on Monday and won't have time to commit to this type of problem before I go. I'll pop into the forum while I'm away as time permits so if you don't get sorted out in the next 2 weeks you're welcome to send me a pm and I'll schedule a visit when I return. 

Good luck.

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## BillH

> I love a good fault that you can get your teeth into but unfortunately I'm flying out again on Monday and won't have time to commit to this type of problem before I go. I'll pop into the forum while I'm away as time permits so if you don't get sorted out in the next 2 weeks you're welcome to send me a pm and I'll schedule a visit when I return. 
> 
> Good luck.


Many thanks for the kind offer!  Still feeling a bit shell-shocked after this mornings "re-wiring" of the RCD exercise - in the process with the multiple on/offs I now seem to have two UPS units that don't work anymore!

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## BillH

After three or four sparkies on the same problem, with no progress other than outwardly through my bank account, I am amazed at just how incapable these guys have been at even reasonably logical (scientific) fault finding.  This is very worrying as it does not say much for the quality of training.  They all tell stories about how many times they have been blown off their ladders (equally worrying) but anything beyond basic wiring up of a new installation appears to be beyond them.

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## Dave A

There's no doubt fault finding is the real test of a sparky's understanding of their trade - and nuisance tripping can be a real hunt for the proverbial needle in a haystack (or a pile of needles as Andy points out).

Struggling to nail down the cause of the problem first time around is kinda understandable and forgivable - being unable to separate that outbuilding circuit and get it off the main house earth leakage unit is less easy to accept.

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## murdock

cbi...heineman...same company...the older earth elage units where the better ones...the new ones...seem to be a lot more "sensitive" to voltage fluctuations etc...or so i am told by the experts...but if the earth leakage is really old and has been causing endless tripping problem...it "could be a place to start...

having 2 earth leakage units in series is just unpracticle...the ony reason you fit one in an outbuilding...so that the person in the outbuilding doesnt have to keep going into the house to reset it...so you isolate the outbuilding from the main house..etc 

the older type light fittings like the 8 ft double with the big ballast have caused many a headache for me in the past...especially in factories where we have multiple rows of lights...the newer 5 ft and electronic ballast units dont seem to affect the earth leakage unit as much...but then in saying that i dont connect light fittings to an earth leakage unit...and the fatories which i service...i remove the light circuits from the earth leakage...if they create an issue.

dave the sound of it is bad...but in theory only 15 amp plug sockets and a few other items as per sabs regulations are required to be on earth leakage...maybe they should try an insulation resistance tester "megger" before blowing them selves up... dont ever try that if you work near RBM or any of those big companies in richards bay...the DOL are like lice in that place :Big Grin:

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## murdock

> After three or four sparkies on the same problem, with no progress other than outwardly through my bank account, I am amazed at just how incapable these guys have been at even reasonably logical (scientific) fault finding.  This is very worrying as it does not say much for the quality of training.  They all tell stories about how many times they have been blown off their ladders (equally worrying) but anything beyond basic wiring up of a new installation appears to be beyond them.


and what is even more scary is when you work on industrial sites where these so called qualified sparkies work...in close proximity...i get nervous...and when you get called out to repair something they break while working..then tell the customer that it must be something i did...well then i just dont play nicely anymore...in fact the last incident...i had set up a meeting with the site engineers and the other company owner...the owner went to site an hour before the meeting and realised that it was in fact his electricians fault...and in fact it was a 5 pin plug and not a 4 pin plug...he was too embarressed to attend the meeting...instead rather got someone else to call and apologise...but here is the joke he is still the prefered contractor on site...regardless of the fact that his staff have been sited for numerous safety violation...need i say more... :Shutup2:

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## SparkyScott

So the lights still trip in the garage even though its been rewired?are they new light fittings?

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## Dave A

> maybe they should try an insulation resistance tester "megger" before blowing them selves up...


They do  :Wink: 

And it's not that big a blow for crying out loud. Technically it isn't even a contravention of regs as long as the plugs are on earth leakage (and earthing, isolators etc. are all where they should be).

Certainly out of the question on heavy current stuff - but then in those situations nuisance earth leakage tripping doesn't normally come into play anyway.

I don't know how many times it's been the geyser after being left off for a few weeks that's been the culprit.
And stove plates at coastal holiday flats! Don't get me started on those...

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## BillH

> So the lights still trip in the garage even though its been rewired?are they new light fittings?


Yup, installed less than a year ago.


Just had the latest trip. Guest plugging in a MacBook charger!

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## Dave A

It sounds like something along the lines of Andy's post 15 is looking more and more likely. You've got something (or an accumulation of things) which is producing a steady drip of current to earth and it just takes the smallest of capacitance take-up to push the earth leakage unit to trip.

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BillH (07-Jan-12)

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## BillH

So would splitting the circuits in the house over two RCDs help to minimize the frequency of this?

By the way, the RCD tripped this morning when my wife turned on the kitchen lights, which are not connected to the earth leakage circuit!

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## Justloadit

Does your electrician own an earth leakage tester?
This would help in checking at what current the ELCB trips at, with loads connected and with out loads connected

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## mikilianis

I have been caught out by earth leakage units on many occasions, the trickiest was a missplaced neutral do yourself a favour and have the neutrals cheched. All circuits on E.L.U. must have the neutrals going through the E.L.U. as well.Also had many multiplug faults. But the majority have been neutral faults,
Regards
Mike

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## Sparks

Now that says a lot. The fact that the kitchen lights are not supplied from the ELCB yet still cause it to trip can only mean a stolen neutral. You need to disconnect all the neutrals and switch everything on, then 1 by 1 reconnect the neutrals. The guilty circuit is bound to be given away by the ELCB. Not quite sure if I understand correctly but if the garage lights are tripping in the house it could mean that there are 2 circuits to the garage. The "original" garage light & plug circuit which was possibly "replaced/upgraded" with a heavier circuit & sub DB, where the sparky never disconnected the "original" "mixed" circuit. Subsequently there could have been extensions done with the wrong neutral.


What are the chances of you posting photos of the insides of the 2 DB's?

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BillH (08-Jan-12)

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## BillH

> Now that says a lot. The fact that the kitchen lights are not supplied from the ELCB yet still cause it to trip can only mean a stolen neutral. You need to disconnect all the neutrals and switch everything on, then 1 by 1 reconnect the neutrals. The guilty circuit is bound to be given away by the ELCB. Not quite sure if I understand correctly but if the garage lights are tripping in the house it could mean that there are 2 circuits to the garage. The "original" garage light & plug circuit which was possibly "replaced/upgraded" with a heavier circuit & sub DB, where the sparky never disconnected the "original" "mixed" circuit. Subsequently there could have been extensions done with the wrong neutral.
> 
> 
> What are the chances of you posting photos of the insides of the 2 DB's?


Would you please explain what this stolen neutral issue is please? All the sparkles I have had here have solemnly stated that this could be the problem, but have not been able to do anything about it.

I will take some pictures. I had intended to yesterday but when the sparky got into a panic when he found he did not know how to desire the outbuildings from the house el, and everything started tripping (two ups units got fried during the many off and one) I did not get around to it.


Still no recommendation for a good cape town electrician? Maybe there arn't any?

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## Dave A

> All circuits on E.L.U. must have the neutrals going through the E.L.U. as well.


Also the neutrals for all circuits *not* on the ELU must also not be on the ELU neutral bar.

Crossed neutrals don't constitute my definition of nuisance tripping though. That's a permanent wiring fault that should be easy to identify.

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BillH (08-Jan-12)

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## BillH

Based on what I have learnt through this forum, I am going to do the following to reduce the "capacitance" problem:
Appoint a registered electrician to:

1.  Get the garage ELU wired correctly;
2.  Take my office's dedicated plug circuit off the ELU completely - the plugs in the office are all in cupboards and can be "red plugged".  
3.  Split the remaining circuits on the DB into 2 ELUs (there is space for another one).

Agreed??

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## AndyD

Sounds like a good plan to alleviate the inconvenience factor. The plan isn't likely to actually remedy the core problem although if the contractor has his eyes wide open he may come across the problem during the work.

@ Dave, your right, the definition of nuisance tripping doesn't include wiring faults. Nuisance tripping is when a protective device trips for no valid electrical reason. I'm also guilty of using the phrase out of context and most customers assume that nuisance tripping means any tripping fault that'sa nuisance to them.

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## Sparks

So many possibillities, and more than enough knowledge on the forum, but without actually being on site it is impossible to trace the cause.

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## bergie

bill,i can help you out. the only problem is i am travelling from blouberg.it would add an hour each way onto every trip,making it expensive.pm me if you need me

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## murdock

if the neutrals are conected on the wrong neutral bar...as soon as you apply a load the earth leakage will trip (should trip)

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## Adam Mashinini

cbi, let's see, their e/l, i dont use, their switchgear, i dont use, their anything they make or touch, i dont use.

do yourself a favour, buy a lear e/l at around 210 rand, replace the e/l and see if the problem still exist. if so, then from there on it is a process of elimination. eliminate circuit by circuit (that means live AND neutrals) until you get the SOB. sometimes it is more than 1 circuit, but u will get there, should not take u more than 1 to 5 hours.

or, get an expierenced eleccie to do it for u, should not cost you more than 12 grand. :-)

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## AndyD

I've haven't had problems with CBI equipment as such, it's okay, it's just overpriced. I can buy Merlin Gerin cheaper than CBI so it's a no brainer. 
I would ramp test the RCD first and check the disconnect times before replacing. RCD's that nuisance trip when there's no fault are very rare, 99.9% of the time if an RCD trips there's a fault that's causing it.

Did you get the problem sorted out by the way Bill?

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## bergie

i went through there and took the garage db off the main earth leakage. i didnt even try looking for faults as there was about 15 circuits on 1 earth leakage and the accumalative earth faults must be very high. i recommended a new d.b. with up to 2 extra elr's. once that is done it will be very easy to find any faults. there might not actually be any fault.

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## murdock

been having a fair share of these random tripping issues...especially the weekend ones where people get a call to tell them that the alarm battery hasn run flat( i know you should have the alarm on e/l )i wasnt the fool who wired it like that...and others who arrive at work on monday morning and the office power has tripped...this has been happening for a couple of weeks now.

then i got an interesting call today...a customer complaing about a power surge at 1 am on saturday morning...which caused a problem with some electronic equipment...then while chatting about that issue another person indicated that the saturday night there was an outage in the area...starting to wonder if its not time to connect the fluke 435 to the db and monitor the power over the weekend...why i am concerned is the fact that everything is shut down for the weekend...yet it still trips...got me thinking.

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