Discuss Problem - Fridge Freezer Causing Nuisance Rcd Tripping. How Do I Rectify? in the Electrical Appliances Forum area at ElectriciansForums.net

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The client is looking into the warranty but it may come down to me installing a dedicated supply, hopefully then any electrical spikes generated by the fridge freezer won't be caught by the RCD, otherwise i'll take it off the RCD and label it accordingly.

I would PAT test the appliance as i'm qualified in that area but the I don't have a tester.

Thanks for all your swift responses to my query. :)
 
........any electrical spikes generated by the fridge freezer won't be caught by the RCD, otherwise i'll take it off the RCD and label it accordingly.
This whole fridge affair is getting more confusing to me. How is the RCD catching spikes? Surely this would be a taylormade job for a surge arrestor or MOV device. How is the fridge generating spikes other than the simple switching on and off of a standard induction motor?

I still don't understand why it's accepted practice to hard wire the fridge on a spur circuit with an isolator rather so you can omit earth leakage protection rather than having the low ins fault localised and repaired.
 
A fairly common problem with some modern frost free fridge freezers is earth leakage on the defrost heaters. If the unit is designed to run off a 13A plug top then there should be no problem with it doing so. Sounds more like a job for a Domestic Appliance Engineer or the manufacturer.


Had the same fault on an American style FF some months back. The manufacturers repaired FOC as it was a common fault on that particular model.

Hope it helps.
 
I still don't understand why it's accepted practice to hard wire the fridge on a spur circuit with an isolator rather so you can omit earth leakage protection rather than having the low ins fault localised and repaired.[/QUOTE]


i would say that this practice is not to omit earth leakage on the freezer, but to prevent a fault on another part of the installation tripping the RCD and taking out the freezer circuit with it. not nice to come home after a few days away and find a freezer full of soggies
 
i would say that this practice is not to omit earth leakage on the freezer, but to prevent a fault on another part of the installation tripping the RCD and taking out the freezer circuit with it. not nice to come home after a few days away and find a freezer full of soggies
I agree there's a certain amount of inconvenience if it does trip a RCD but removing it from earth leakage protection is more dangerous for the user so how is this justified?
 
as long as it's a dedicated labelled socket, it's acceptable if surface wired.relying on the overcurrent device for fault protection. alternatively, the freezer can be wired to a RCD socket or RCD FCU.
 
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The client is looking into the warranty but it may come down to me installing a dedicated supply, hopefully then any electrical spikes generated by the fridge freezer won't be caught by the RCD, otherwise i'll take it off the RCD and label it accordingly.
Thanks for all your swift responses to my query. :)


You need to know what is going on with the freezer and the other circuits in terms of earth leakage before you just remove the safety feature of a protective rcd! As Des said earlier is it a cumulative fault? Putting fridges on dedicated circuits is not to allow faulty appliances to be used but to prevent nuisance tripping wasting all the frozen peas. If there is a big problem with the fridge you could end up giving people nice tingly feelings.
 
This whole fridge affair is getting more confusing to me. How is the RCD catching spikes? Surely this would be a taylormade job for a surge arrestor or MOV device. How is the fridge generating spikes other than the simple switching on and off of a standard induction motor?

I still don't understand why it's accepted practice to hard wire the fridge on a spur circuit with an isolator rather so you can omit earth leakage protection rather than having the low ins fault localised and repaired.


Of course protecting a circuit with an RCD is more desirable because of the added protection but if nuisance RCD tripping can't be avoided because of the way the appliance operates then another solution must be found.

Since I started this thread iv'e done a little research into the problem and had a look in BS7671.

The clients fridge freezer is quite large and has all the extras and i'm assuming either the defrost function or the ice maker function is causing the problem and also there are alot of other electrical items plugged into this ring circuit and as reg 314.1 states in BS7671, this should be avoided to reduce the possibility of unwanted tripping due to excessive protective conductor currents.

I came across a site that gave me some useful information you might find interesting Marv...

Possible Causes Of RCD Tripping

Faulty appliance – unplug all electrical appliances, does the RCD reset OK? If the RCD resets OK plug the appliances back in one at a time. Reset the RCD as you plug each appliance back in to find the faulty appliance.

Incorrect RCD current rating – RCDs have ‘current ratings’ similar to fuses. The current rating is the current that trips an RCD. The current rating of the RCD could be too low. Seek advice from a qualified electrician.

Poor quality RCD – poor quality RCDs can trip when they shouldn’t. Seek advice from a qualified electrician.

Items with motors or pumps starting – many items with motors or pumps, for instance showers and pond pumps, cause momentary electrical spikes that are big enough to trip RCDs. Seek advice from a qualified electrician.

Older washing machines – aging washing machine heating elements can cause momentary electrical spikes that are big enough to trip RCDs.

Certain wash cycle phases – some cycles of the washing machine, for instance the spin cycle, can cause momentary electrical spikes that are big enough to trip RCDs.

Certain dishwasher cycles – some parts of the dishwasher cycle draw a lot of current, a faulty component, for instance the motor, can trip an RCD.

Overloading a washing machine – too many items in a washing machine can cause certain wash cycles, for instance the spin cycle, to trip an RCD.

Fridges and freezers cooling – the fridge or freezer cooling motor starting.

Turning a sun bed on – a sun bed uses a lot of electrical power, the surge in electrical power can trip an RCD.

Turning an heating element on after a long time of being off – moisture in heating elements can trip an RCD, for instance in a sun bed or electric fire. Try resetting the RCD a few times so that the heating element can cause the moisture to evaporate.

Pond pump faulty – pond pumps sometimes have to ‘work very hard’– for instance when they have ‘digested’ part of a plant from the pond. Check your pond pump for blockages.

Moisture in outside electrical distribution boxes – remove the supply and dry the distribution box. Check the weather seals have not perished.

Moisture in outside electrical sockets – remove the supply and dry the electrical socket. Check the weather seals have not perished.

Ice maker on a fridge – a faulty ice maker on a fridge can cause ‘nuisance’ RCD tripping.

De-frost timer on a fridge or freezer – a faulty defrost element on a fridge or freezer can cause ‘nuisance’ RCD tripping.

Central heating elements – faulty heating elements can cause an RCD to trip when they are turned on by a timer.

Water heating elements – faulty water heating elements can cause nuisance RCD trips when the thermostat tells them to heat the water.

Moisture in wiring – moisture in the electrical wiring is a common cause of RCD trips. Have you just emptied a bath? Taken a shower? Is it raining – rain can get into the electrical wiring under the floors or in the loft.
 
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You need to know what is going on with the freezer and the other circuits in terms of earth leakage before you just remove the safety feature of a protective rcd! As Des said earlier is it a cumulative fault? Putting fridges on dedicated circuits is not to allow faulty appliances to be used but to prevent nuisance tripping wasting all the frozen peas. If there is a big problem with the fridge you could end up giving people nice tingly feelings.

Of course getting to the problem of the fault is the main concern which is why iv'e advised the client to look into the warranty. But after doing my research I think alot of these newer model fridge freezers have functions that may cause sensitive RCD's to unfortunatley trip. Another theory I have is there might be too many items plugged into this circuit causing excessive protective conductor currents as stated in BS7671 reg 314.1. Whatever the problem at the least the RCD is doing its job.
 
I am now wondering how these excessive protective conductor currents are being generated but the phenomenon must exist otherwise BS7671 wouldn't refer to it.

Perhaps because the cpc's run next to the line and neutral conductors maybe a small emf would be generated and transfered to the circuit cpc's within the cable runs which the RCD is picking up.

But then if i remember rightly the emf's produced in the line and neutral conductors are supposed to cancel themselves out so maybe thats not the reason or there is is some residual current left and because of the many items connected to the circuit all these currents might add up to a small current that the RCD could detect.

Does anyone have any idea's on how these protective conductor currents are being generated as refered to in BS7671?
 
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I have traced the nuisance tripping down to the fridge freezer and im wondering how best to go about rectifying the problem

Is the nuisance tripping an appliance fault or an accumalation of circuit leakage ?

If it is a fault on the appliance. It may be a better option to clear that fault, rather than altering the fixed installation to permit the fault or leakage to go undetected

I think you could be right it might be the accumalation of circuit leakage as there are quite a few items connected in this circuit. Cheers.
 
The functional earth leakage exist usually on computers and such that have a deliberate functional earth facility, for the sound operation of those appliances

Household junk is usually leakage free, unless there is a deterioration in the appliance itself
Circuits with rcd protection should be split up to an extent that a leakage on that circuit does not take out other circuits
Its a consequence of the rcd anything regulations that we may have these sort of problems
A full rcbo board that takes out only that circuit was what was envisaged by the 17th regs,but economic reality played a part and split rcd boards were accepted as the norm

These however have a very fatal weakness, as you may have found.
Multiple appliances with a little leakage on each can accumalate to trip the rcd where no real problem is evident

If the problem has been diagnosed and found to be the freezer,then why not first measure the amount of leakage and act on whats found
I dont think looking for answers with protective conductor currents is the best approach, nor the modification of the installation to suit an appliance that is not operating now the same as when it was manufactured
 
The functional earth leakage exist usually on computers and such that have a deliberate functional earth facility, for the sound operation of those appliances

Household junk is usually leakage free, unless there is a deterioration in the appliance itself
Circuits with rcd protection should be split up to an extent that a leakage on that circuit does not take out other circuits
Its a consequence of the rcd anything regulations that we may have these sort of problems
A full rcbo board that takes out only that circuit was what was envisaged by the 17th regs,but economic reality played a part and split rcd boards were accepted as the norm

These however have a very fatal weakness, as you may have found.
Multiple appliances with a little leakage on each can accumalate to trip the rcd where no real problem is evident

If the problem has been diagnosed and found to be the freezer,then why not first measure the amount of leakage and act on whats found
I dont think looking for answers with protective conductor currents is the best approach, nor the modification of the installation to suit an appliance that is not operating now the same as when it was manufactured

I'm assuming its the fridge freezer as client advises me the circuit appears to function adequately with it disconnected and once connected the RCD trips after a period of time, I'm guessing when the defrost function or the ice maker function kicks in.
Maybe the fridge freezers operation is just enough to make up a problem current that the RCD is detecting on this circuit.

Thats the bottom line then Des, full RCBO boards are the answer but t the end of the day cost is a bigger factor over convenience and now i'm seeing the inconveniences.
 
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Most earth leakage on a refrigerator will be from the compressor. Normally it is when the compressor windings start to breakdown and leaks to earth.

I'm afraid it's a rock and a hard place really. The client will not most likely want the outlay of a new refrigerator and will be looking at you for a solution. I would first off ramp test the RCD after you have isolated all the circuits and see what it trips at. The trip range on RCD is huge it could be as low as 15mA on a 30mA RCD. If it is pretty low below 20mA then if you have a spare in the van fit this and see if it's slighlt higher, it may well be over 20mA and give you a little extra to play with.

If you got a clamp meter that reads the Earth Current then activate all the circuits and turn on as much as you can and check what the earth current is. If you haven't got one then I can recommend this

Alphatek TEK633 3 in 1 200A AC/DC Clamp Meter. Buy online or callhttp://isswww.co.uk/ACDC-Digital-TR...Alphatek-TEK633-3-in-1-200A-ACDC-Clamp-Meter/

It's quite dear on this site but you can pick one up a little cheaper. I think this is a great piece of kit with the amount of RCDs being used and a great fault finding tool.
 
Alot of electronic devices have filters that naturally put very small currents into the earth this is particularly common with computers and necessitates extra circuits in offices where the demand would not initially warrant it.
 
Just spoke to the client. They had the fridge PAT tested yesturday and it failed so Samsung are coming out to look at it. Ill let you all know what the result of that will be.
 
Most earth leakage on a refrigerator will be from the compressor. Normally it is when the compressor windings start to breakdown and leaks to earth.
Most earth leakage problems I've encountered with fridge freezers are caused by the evaporator defrost elements. Leakage from the compressor windings usually only happens during burnout due to high head press/temp or locked rotor due to mechanical failure.

With air conditioning I've come across earth leakage due to moisture in the refrigerant. Because air cons generally evaporate above zero the moisture doesn't always effect the refrigeration system but it will cause earth leakage. Moisture in a fridge/freezer would cause a blockage at the point of expansion so the fridge wouldn't get cold.
 
The idea of the non rcd protected circuit is that other appliances on a circuit sharing the same rcd could cause a problem and take the freezer out
Take away the buried cable bit and the labelling so that it cant have something else plugged in,the Iee have returned to reality and allowed a dedicated socket ,surface run to be non rcd protected
The freezer non fault is the thinking on this

Makes sense doesn't it
 
I have traced the nuisance tripping down to the fridge freezer and im wondering how best to go about rectifying the problem and staying within the 17th edition regs.

Any ideas would be greatly recieved.

The problem turned out to be a failed heating element which Samsung have now replaced.
 

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