Why would circuit breaker trip every few hours?

Crinkmeister

scarletjim wrote: »

Oh dear, I think I might have caused lots of unnecessary confusion on that point. This picture should help (if it works):

http://img3.uploadhouse.com/fileuploads/22462/22462583c35a36819f1c99c05e48bdaa35357a69.jpg

On the far right, there are 6 black switches - none of these move when the power cuts out. However what DOES move is the single black swith just above the 'RCD protected circuits' sticker. It reverts to the middle (tripped) position after a few hours of being reset. Does that make sense? So what I meant was that none of the individual switches trip, but that main one does.

(NB. The red side appears to work regardless, so we always have lights on even when the 'green side' keeps failing).

You are extracting the straw-coloured clear liquid now, aren't you?:D

scarletjim

brightontraveller wrote: »

Clarify cooker has plug point?
...
Cookers not on RCD You can spend the £7 if it cures fault /symptoms you need spend no more potential to gain if it doesn't take it back no loss or call out engineer they'll likely do same but charge you more than £ 7

Aha I see what you mean. No, the cooker has no plug, just an on off switch on the wall with a light next to it.

Kiran

You put a plug on it earlier didn't you?

brightontraveller

scarletjim wrote: »

Aha I see what you mean. No, the cooker has no plug, just an on off switch on the wall with a light next to it.

If you’ve followed my advice ie phone manufacture etc Buy a new cheap f/f
http://www.currys.co.uk/gbuk/household-appliances/refrigeration/fridges/essentials-cuc50w15-fridge-freezer-white-10116567-pdt.html#srcid=11026

component replacement cost ( callout + labour + materials going to cost more than new ff 99 % of the time + likelihood of solution lasting its gone once will again ? ) cheaper ditch it and get new one , Different scenario if you could change component yourself but if you struggle with a plug possibly not a good idea ?

Heedtheadvice

Or alternatively get a Portable Appliance test done on Fridge freezer.
Dear Brighton traveller, you could have asked if it is an expensive f/f, or new and still under guarantee etc........touch! ?

But seriously again, could maybe be the filter on the fridge freezer causing problems with unbalanced current live to neutral at motor start and PAT ought to be cheap and show this up. If that is the fault and the freezer is expensive and you would want similar as replacement the phone manufacturer and get estimate might be a good way forward.
In general though Brighton is right to point out the throw away society approach should be considered - if you believe the fridge freezer IS faulty.

brightontraveller

Heedtheadvice wrote: »

Or alternatively get a Portable Appliance test done on Fridge freezer.
Dear Brighton traveller, you could have asked if it is an expensive f/f, or new and still under guarantee etc........touch! ?

But seriously again, could maybe be the filter on the fridge freezer causing problems with unbalanced current live to neutral at motor start and PAT ought to be cheap and show this up. If that is the fault and the freezer is expensive and you would want similar as replacement the phone manufacturer and get estimate might be a good way forward.
In general though Brighton is right to point out the throw away society approach should be considered - if you believe the fridge freezer IS faulty.

Cost of F/F is irrelevant for engineer more a concern to client ditto if still in warranty

Unfortunately PAT Testing is hit and miss at best ? class 1 At a guess fridge freezer is classified? Would be optional test and surprise surprise many manufactures don’t cover specific fail in warranty ( to be fair to them didn’t matter till RCD became the norm )

Could require long run/soak test *go through all conditions. You can get testers appliance/item powered through and runs indefinitely or set time, gives all readings. exact time fault occurs etc plug in leave come back next day etc, But 95 % of Peeps testing don’t own these type they tend to cost 3 - 5 times more than your bog standard £500 to £1k ones

Or take item away run test etc again higher cost Even if test shows fault none show what’s faulty so again down to engineer what they replace ? Dibble about changing component e.g. cap etc or complete motor I know which most go for? ,

Your not wrong there are lots of alternatives possibly is a trapped cable that getting squashed as you walk over it but where do you end especially giving free advice? For me OP should explore all just my opinion there wasting there time doing so ? Call engineer or change F/F?

scarletjim

Hi fellas, just to give you an update, having looked at literally hundreds of forum threads from all over the net about freezers tripping RCDs, the main reason seemed to be the defrost heater. I looked that up, and discovered that it is actually relatively simple to remove and test - so last night, we did exactly that. Having unplugged everything (obviously) and let the FF thaw a bit, we followed the instructions and managed to remove the defrost element. This morning I bought a cheap multimeter, and followed the instructions for continuity testing. Whereas a paper clip was giving a reading of near zero, the terminals of my defrost heater give a reading of about 120. Having Googled that, it sounds like it could be the problem (?) - so I've ordered a new one of those, and will try to fit it when it comes. I know I'm not experienced at such things (as you've seen in this thread!), but with my girlfriend's electrician dad on Skype video from Poland to watch me in action, it should be fine.

If that fails to solve the problem, then I plan to contact Domestic & General and ask them for a 'repair and protect' policy (about £180 a year), but will need to check that they will deal with my problem before I agree to the contract (as my FF appears to be 'working' in terms of doing it's job, it just keeps tripping the electric, I need to ensure that's covered). Failing that, I've done all I can, I'll have to dig into my savings and buy a new one (not a direct replacement though - this one that was here when I moved in cost the previous owners £1,620 according to the receipt from 2011 - that is utter madness, you can buy a whole kitchen for that!)

Thanks for all your help - I'll report back tomorrow evening or Sat!

bsod

you've probably just tested it's resistance, a heating element is going to have a higher resistance than a paper clip. A reading of (120 ohms?) doesn't mean no continuity (infinite resistance) or a faulty element

a methodical diagnostic approach is much cheaper than relying on advice from bloggers, forumers and youtubers, demonstrating the effect of continuity on a multimeter doesn't require a paper clip, just touch the multimeter probes together.

turn the freezer off and fully defrost it manually. Check drain holes and reservoirs are clear, inspect for any obvious water/wire contact

turn off any appliances (irons/washer/microwave/clock/cooker hood?) that don't need to be on continuously at the wall socket. at the consumer unit, turn off any rcd protected circuits (marked 15-20) that don't need to be on continuously, garage, outside lights, water heater etc.

plug the freezer and all other suspect <13A (one by one) appliances into a

http://www.screwfix.com/p/masterplug-rcd-adaptor/63731

and hope it trips before the consumer unit rcd. If it does, you've proved it's the fridge freezer or another appliance, and stopped the rest of the house tripping for £6, and have a handy rcd backup for those gardening chores.

rcd's can also have faults, and are far cheaper than a freezer.

if you do prove it's the fridge freezer, you may be able to narrow it down further by adjusting the thermostats of each

scarletjim

bsod wrote: »

if you do prove it's the fridge freezer, you may be able to narrow it down further by adjusting the thermostats of each

Could you explain this further please? After a painful few days last weekend spent trying different combinations of appliances, we know it's the fridge freezer (just to explain, it is the only appliance that trips the main RCD when everything else is off, plus to double-check we plugged it into a socket on a different circuit, and it still tripped with all other appliances disconnected. Since we unplugged it, no trips now for 3 days).

However if adjusting thermostats can help to identify the problem, i'd be eager to understand that.

With regard to the defrost heater, when we removed the panel to get to it, there was a lot of thick solid ice on the back panel and round the components - however I don't know what it looks like normally, so I can't really be sure that indicated a problem. With regard to resistance, I simply followed what it said in the instruction manual - that if it didn't beep, there was no continuous circuit. I then looked up the resistance values here:

http://siber-sonic.com/electronics/ContTestRead.html

...where it suggests (or so I thought) that my reading of 120 meant a lot of resistance and potentially a problem - now sounds like I my have got that wrong. Not to worry, the new defrost heater will arrive today, we will fit it and see waht happens. If I can then somehow use the thermostats to identify the issue further, then great, but if not, then I'm happy to pass this on to a pro.

It's not that I won't spend the money when needed - in fact I'd have been happy to get someone in a week ago if I knew what I wanted them to do! It's more that I'm sick of the old me, just calling someone every time anything went wrong, making no effort myself to understand or resolve, especially as sometimes you can end up paying £200 for a simple task I could have done myself. But I've probably gone too far the other way in thi instance...

Heedtheadvice

Bsod is right. You have been led the wrong way up the garden path!!
120ohms corresponds to a heater rating of 500watts (in round figures) which seems fine. Your new one should be very similar.
The concern is not the heater resistance that you measured (you need that between line and neutral to create heat) but a low insulation resistance between the live or the neutral (or both) and earth. This can be either to part of an earthed chassis, an earth wire, around components that have bare terminals or owing to faulty components. Readings here should be in millions of ohms (for no problems) rather than the operational reading of 120ohms you have measured.

Given that you have been disconnected for three days and no tripping then it is very probable that the fridge freezer is your culprit. Note that does not rule out problems with other circuits/appliances but not a big enough issue to trip the RCD.

What is concerning was your comment about ice on the components as ice/water/corrosion etc between contacts/wires etc and earth could easily give rise to your fault. Ideally testing should be done at high voltage typically 500volts or more to measure the insulation resistance. Your multimeter will be doing resistance checks at just a few volts and should not be used to prove safety however it may well show up the low insulation reading. It is worth giving it a go.

Test resistance (with the supply wires disconnected from the mains!!!) in a similar manner to when you measured the heater but ensure to test from live to earth and neutral to earth. If you heater is currently disconnected do the same on it. If it has no earth wire check to the casing instead.

If it has been the moisture you report readings might well be fine now if it is dry but it would be worth inspecting where there was ice to see if there is any chance the ice would be in contact with the site's conductors or terminals etc or if there is any corrosion here.

You may be able to make progress now and maybe save the cost of a new fridge freezer or call out

Report back what you find.