Help! Cooker trips RCD.

[Goody]

Hi,
An electrical cooker stays on for a while and trips the RCD. When the RCD switched back on straight away, the cooker stays on for a length of time and trips again (doesn't trip straight away). The circuit tests OK and the MCB stays on all the time.



What could be issue and where do I look? Thanks!

 

[telectrix]

element breaking down when hot. get int the controlls, disconnect 1 at a time till you find the dodgy 1.

 

[Goody]

element breaking down when hot. get int the controlls, disconnect 1 at a time till you find the dodgy 1.

We will do, thank you!

 

[MarkieSparkie]

Another possibility is the cooker terminal box check for insulation breakdown due to thermal effects and heat damage caused by poor termination, particularly on thermo-plastic terminal boxes.
In recent times some cooker manufacturers instructions have specified making the cooker connection in heat resistant flex. However, I am finding a lot of melted/burnt appliance terminal boxes on cookers that have been poorly terminated with flex (Only 1 in 30 years terminated in T+E). If you are terminating flex it is wise to use crimped ring terminals on the flex ends to minimise the chances of the screw connections loosening under repeated load/heat cycles causing damage to the terminals and/or the box.

 

[Goody]

Another possibility is the cooker terminal box check for insulation breakdown due to thermal effects and heat damage caused by poor termination, particularly on thermo-plastic terminal boxes.
In recent times some cooker manufacturers instructions have specified making the cooker connection in heat resistant flex. However, I am finding a lot of melted/burnt appliance terminal boxes on cookers that have been poorly terminated with flex (Only 1 in 30 years terminated in T+E). If you are terminating flex it is wise to use crimped ring terminals on the flex ends to minimise the chances of the screw connections loosening under repeated load/heat cycles causing damage to the terminals and/or the box.

As telectrix pointed out, I think it is a case of the elements breaking down. I checked all circuits and asked them to try. They turned on a bigger element with a pan on and a smaller element without anything on. It tripped after five minutes. I asked them to turn off the smaller one and it stayed on since. This concluded that the smaller one a dodgy one (they probably knew this already). The cooker must be at least 10 years old.

 

[SimpleSimon]

If you can, find the instructions which could giv you a break down of the Wattage for different sized elements. Using that calculate what the resistance should be per element than test using low ohms resistance and see how much of a break down you get.....but thats long and youve now solved it.

Sent from my GT-I9100 using Tapatalk

 

[Deleted member 26818]

You can usually see which element is the problem, as the element often glows brightly at the point where the break is.

 

[cakey]

Or get a new cooker

 

[Goody]

If you can, find the instructions which could giv you a break down of the Wattage for different sized elements. Using that calculate what the resistance should be per element than test using low ohms resistance and see how much of a break down you get.....but thats long and youve now solved it.

Sent from my GT-I9100 using Tapatalk

That cooker is probably more than 10 years old and I have the remote chance to get hold of the instructions. Turning one by one to see if the RCD trips was an easier option for me and it worked. Thanks for the input, anyway!

 

[Goody]

Or get a new cooker

Or simply don't use the offending one! Would save some money.

 

[jks]

It could be that,one of the stats is arcing when it cuts out at temp