Problem - Fridge Freezer Causing Nuisance Rcd Tripping. How Do I Rectify?

[KDT Projects]

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.

 

[Des 56]

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

 

[KDT Projects]

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.

 

[malcolmsanford]

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.

 

[pushrod]

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.

 

[KDT Projects]

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.

 

[Marvo]

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.

 

[Des 56]

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

 

[KDT Projects]

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.

 

[Marvo]

Thanks for the info KDT, it's nice to find out the end result.