Testing appliances for faults?

[corbs]

Evening all,
I have a problem in our house at the moment and would like to rule out (or find) our appliances as the problem prior to calling in the heavy artillary (read the sparky). We have an annoyingly regular electrical fault which causes the safety switch to go on the fuse board around 6am usually once a week. I have a multimeter and would like to test our appliances but dont really know how to use it. I dont want to do any of the greenie work myself, just find what is causing the problem and get it fixed or remove it from the house alltogether. Any assistance/guidance on how to use the multimeter to check would be greatly appreciated...

Corbs

[DavidG]

What happens at 6am.
What electrical things are in use.

With the suspect items unplugged
Use your multimeter on the OHMs range
and measure between the earth pin and either of the others.
Should measure in the Meg Ohms.

[rona]

By the sound of it, it is possibly a couple of appliances that are switched on and are overloading the circuit at 6.00 am when the toaster, or electric jug or some other appliance is switched on. I s it the same circuit breaker each time that is throwing out ?
If this doesn't seem feasible, I would suggest you talk to a sparkie, just to be on the safe side.

Cheers,
Ron.

[abitfishy]

Few possibles (although I could be way off):

Off Peak Hot water does something at 6am???
Back to base alarm dials base (a lot do this without you knowing as a test each day to ensure the back to base is operational) Sounds strange but I have known of an odd problem that was traced back to this.
Do you have any sort of timer or anything in the garage, or maybe heatlamps (I have reptiles, so heatlamp comes on certain time of day)

You might need to think hard.....

[spartan]

Corbs from pusser to from a mango sparky....

throw away the multi-meter. You probably have an earth leakage problem if it is your safety switch that is being blown.

Now their are a range of simple tests that you can do, quite legally to test this. In fact if you call your local electricity supplier (Country Energy in ACT??) they would tell you to do a number of things....

As indicated above look at things that kick in at 0600. Now I'd be thinking off peak hotwater - but it usually comes on twice a day so you would have that problem twice....except......because you live in Canberra there is evey possibility that there is condensation present in the AM that isn't there at say 2300 when the it turns on at night....

After the hotwater I'd check fridges, freezers, pool pumps, air con.....

Its a pain, but if you can turn them off before 0600 and see if it still happens you can rule that out.

Another possibility is that your safety switch is on the way out.....You will always have earth leakage from various devices but it shouldnt trip until 30MA, if your background earth leakage is high because of you applicances a small surge when another leaky appliance comes on line could be enough......look at your hot water first old son....

and the on the beam up,rest, ready etc.....

[corbs]

We are in a Defence house and DHA will send a greenie around to check the problem. If it turns out to be one of my bits of kit then I get the bill so I just want to go through the house and test all of my equipment. As it is not a daily thing that happens all the time, I have not been able to isolate the problem to an area of the house. I thought it was an extension cord which I have disposed of but it happened again last night. What I would like to know is how do I use the multimeter to test my equipment. What settings and what should I expect to see for a good/faulty reading? Thanks for the advice provided so far...

Corbs

For Spartan (Push up position ready, lower, raise, lower, raise, lower, raise, in that time continue)

[Dan]

A multimeter won't be much use. You'll need an insulation tester (megger).

[corbs]

What happens at 6am.
What electrical things are in use.

With the suspect items unplugged
Use your multimeter on the OHMs range
and measure between the earth pin and either of the others.
Should measure in the Meg Ohms.

David,
I had actually missed your reply, not sure what happens at 6am but its not regular enough for me to narrow the search down. I was playing with an iron last night (of course it was unplugged, I dont want to burn myself) before posting in the OHMs range. When the probes are apart, I get a reading of 1 and when + & - are connected it reads 0. On the iron across the + & - I get a 0 reading and from either +/- to the earth I get a reading of 1. The question is, what should I expect to see in a faulty reading? Its one thing to do a test, but another to recognise a problem once it presents itself.

Corbs

[DavidG]

corbs
Which end of the ACT are you.
I am down south.
I can show you faster than I can explain.
Dave..

[thatirwinfella]

okay, try this....

• set the multimeter to ohms scale
• disconnect the appliance from the wall
• apply one test lead to earth and the other to the top left pin [the active]. The result should be infinity/OL [over limit] huge, etc]
• do the same again but between the top right pin [neutral] and earth. the results should be the similar as the above test.

If anything is under 1M ohm, put it aside as suspect.
thats about the most you can do without some fancy equipment.

if you find anything that seems a bit sus, then take these to a test and tag company or appliance repairman. if one of these is in use at 6 in the morning then it will most likely be the cause of the tripping.

most HWS aren't connected to an RCD for the reason that they do frequently nuiscance trip, so this is unlikely to be the reason, but still possible.

are you certain that it is the RCD/earth leakage tripping and not the circuit breaker. on the RCD there will be reference to 30ma as well as a higher aperage, the breaker will generally just have an amp rating, 10A, 16A etc. the theories suggested about overloading make sense if it is the circuit breaker, but would be unlikely to trip an rcd.

[edit]

another thing you can do is a visual inspection of appliances. if the lead is damaged in anyway get it repaired. if it doesn't work properly, get it repaired.

if the lead is in good condition on the outside [insulation intact, etc] plug it into the powerpoint and turn it on. turn the appliance on, and wiggle the lead about across the entire length. if you are wiggling the lead and the power drops out, or the appliance goes on and off, you have found a problem in the lead. something like this could very easily be the cause of your problem.

[corbs]

David,
I am up North (Gungahlin) will be in Sydney for the next couple of weeks but I might send you a PM if I remember when I am coming back next to make an appointment with you.

Thatirwinfella (thats a mouthful),
Lot of info there, will have a play around and see what I can find. I will have another look at the fuse board to see if there are any markings on the switch that is going off. Will test some equipment around the house to see how it all goes too.

Thanks for the assistance

Corbs

[DavidG]

Corbs
PM me when you are ready, gives me an excuse the take my new motorbike for a run.

Everything should read very high to open circuit when measuring from earth to either other pin.

Think about things on timers like
watering system,
fans, heaters.
Fish tank.
Pool filter. etc.

Dave..