Jump to content
mecheng46

Oven tripping mains supply

Recommended Posts

mecheng46

Brand new Zanussi double oven. The oven has been given to me as brand new and faulty.

 

I switched on the bottom oven and the fan started with no issues. After a minute the mains supply tripped.

 

I tried the same with the top oven and the same thing happened.

 

The old oven was same brand, power rating, amps etc.

 

I don't want to keep trying the oven if there is a chance i will cause more damage.

 

I had a look on the internet and people suggest moisture in the heating elements, this oven has 4 elements, surely can't be all 4 of them faulty. The elements can only be accessed from the back so at the moment I am looking for some advice before i start taking the oven apart.

 

Any advice on where to start with this oven?

Share this post


Link to post
Share on other sites
ProDave

If you had an insulation tester it would be easy.  Without, it's going to be hard. 

 

could well be the fan.

Share this post


Link to post
Share on other sites
Andy™

dampness in a new element is not all that common, but it does happen and it can be dried out reasonably easy but only if you know what you are doing

 

 

Share this post


Link to post
Share on other sites
mecheng46

I can get my hands on an insulation meter tomorrow, what do i need to measure?

Share this post


Link to post
Share on other sites
Andy™

er... insulation resistance?

Share this post


Link to post
Share on other sites
mecheng46
Just now, Andy™ said:

er... insulation resistance?

 

on all 4 elements?

im thinking that if the problem is there on both top and bottom ovens then it must be something common to them

Share this post


Link to post
Share on other sites
Geoff1946

What's common is the neutral connection. These are not switched by the cooker controls.    Only by disconnecting each element and testing it alone can you find which one(s) are guilty.

Share this post


Link to post
Share on other sites
mecheng46

I will test all 4 elements tomorrow, what sort of resistance I am looking for?

 

Can i do the same for the fan motors?

 

IMG-4277_.jpg

Share this post


Link to post
Share on other sites
ProDave

Unplug the wires from each element in turn MAKING SURE YOU NOTE WHICH GOES WHERE and test the insulation of each terminal of the element to earth.

 

If those are okay, test the insulation of the windings of each fan motor to earth.

 

then there is the light bulbs inside each oven,  if you still have not found the problem.

Share this post


Link to post
Share on other sites
mecheng46

I moved the oven to a different location this morning. I will get some readings tomorrow and post here.

 

If I don't find anything wrong with it I am tempted to put some power through the oven and give it a go at the new location. I am still unsure why it took around 1 minute to trip the mains (previous location), I am wondering if it was something to do with their circuit breaker, i seem to remember their circuit breaker was 20A and I just found on Zanussi website that this oven requires a 30A fuse.

 

I guess i will find out soon.

Edited by mecheng46

Share this post


Link to post
Share on other sites
Murdoch

Hold on , what’s tripping ? 

 

mcb?

rcd?

 

if it’s the mcb, what’s the rating of the breaker? And what do the manufacturers instructions say about the necessary supply ?

 

are you sure it’s the same load as the old unit ?

 

and what do you mean about the new location ?

Share this post


Link to post
Share on other sites
mecheng46

new location means i brought the oven to my house, before it was in a different house. I have the same oven in my house with the same rating so I am confident if there is nothing wrong with the oven then it will work fine at my place. Whilst is out I will check the elements to make sure are ok, if they all seem ok i will give it a go.

 

I am not sure if it was mcb or rcd. Original manufacturer suggests 30A and the guy mentioned to me that he changed the circuit breaker with a new 20a one, old one was 20a too.

 

This might be the issue but whilst the oven is out i will take some readings just to double check.

Share this post


Link to post
Share on other sites
apprentice87
Just now, mecheng46 said:

new location means i brought the oven to my house, before it was in a different house. I have the same oven in my house with the same rating so I am confident if there is nothing wrong with the oven then it will work fine at my place. Whilst is out I will check the elements to make sure are ok, if they all seem ok i will give it a go.

 

I am not sure if it was mcb or rcd. Original manufacturer suggests 30A and the guy mentioned to me that he changed the circuit breaker with a new 20a one, old one was 20a too.

 

This might be the issue but whilst the oven is out i will take some readings just to double check.

 

BIG difference..

Did you actually get any elements to heat up, or did the little motors trip the power off.. [Do they run separately to the elements??] I have no idea, do not have a cooker..

john..

Share this post


Link to post
Share on other sites
Murdoch
Just now, mecheng46 said:

This might be the issue but whilst the oven is out i will take some readings just to double check.

 

Interesting response, do you know what you are looking for ?

Share this post


Link to post
Share on other sites
mecheng46

I am looking to find out why this brand new oven was tripping the mains. Was there a problem with his mains or is there a problem on the oven? That's what I am looking for.

 

only thing i experienced was the fan motor started spinning and after a minute or mains supply tripped, same thing on both top and bottom ovens, that's it.

 

The more i think about it the more i believe that it was possibly his circuit breaker and that it was under-rated (20a instead of 30a), that's why it tripped after a minute, on both ovens same amount of time.

 

I took the oven of his hands with the plan that it will be a faulty element or a fan motor, change it and use the oven to replace mine (same model, brand etc)

 

It's unlikely to be both the top and bottom ovens faulty on a brand new unit, also i won't expect it to run for a minute before it trips.

 

Saying all these, i am not an expert on this kind of stuff so i might be wrong.

Edited by mecheng46

Share this post


Link to post
Share on other sites
Andy™

you also need to test the elements when hot... the reading can be completely different to that of cold

Share this post


Link to post
Share on other sites
ProDave

Okay, when you do your tests note exactly what happens.

 

It is IMPORTANT we know if it's an rcd or an mcb that trips. If you are not sure, take a picture of what trips and post it.

 

Does YOUR house even have any rcd's?

 

Turning on ONE oven should not trip a 20A mcb.  If both ovens are on it might, but would probably take several minutes for it to trip and the ovens would be well on the way to warming up by then.

Share this post


Link to post
Share on other sites
binky

just nurse it on very gently and dry it out - nothing leaves a factory without being tested, so as it's brand new it is unlikley to be a faulty element or faulty anything, just damp in the insulation. get it on at the lowest heat possible, leave for 30 mins, nure it up  a bit more and repeat

Share this post


Link to post
Share on other sites
Murdoch
12 hours ago, mecheng46 said:

Brand new Zanussi double oven. The oven has been given to me as brand new and faulty.

 

 

What was said about the fault?

Share this post


Link to post
Share on other sites
ProDave
13 minutes ago, binky said:

just nurse it on very gently and dry it out - nothing leaves a factory without being tested, so as it's brand new it is unlikley to be a faulty element or faulty anything, just damp in the insulation. get it on at the lowest heat possible, leave for 30 mins, nure it up  a bit more and repeat

Not quite.

 

I had a customer bought a range cooker "brand new" from ebay,  It went from elation at the bargain price to disappointment when I connected it and turned it on and it instantly tripped an mcb.

 

The fault was an internal wire had got trapped and pinched between two sheets of metal.  I guess it could have tested okay in the factory if the insulation had not punctured straight away?

Share this post


Link to post
Share on other sites
revjames

I went to a friends mothers house as the oven had gone bang and tripped the supply. Couldnt find anything wrong with the element but couldnt get a supply on to the terminals even though the display was on. Took it out and decided to take it to the workshop for a more thorough look. Realised a bit of faffing was needed with the timer to get element to come on and the bang was the bulb going as it was in tiny fragments inside the cover when I took it off.... Total repair cost £2

Share this post


Link to post
Share on other sites
mecheng46

I am tempted to wire the oven and start it without testing anything and see what happens, this will give me a better idea of what the fault is and when it happens instead of relying on what I have been told.

 

Once i have a better picture and i know what trips and when I can start testing stuff.

 

Assuming it has an unknown fault, is there any danger of damaging something in the house by connecting it up as it stands?

 

My fuse board is an old style Wylex and it used to have fuses when i first got in the house. Few years ago i replaced the fuses with this other type below. The picture is just an example, i replaced the old fuses with the same rating.

 

 

mcb.jpg

Share this post


Link to post
Share on other sites
Murdoch
Just now, mecheng46 said:

I am tempted to wire the oven and start it without testing anything and see what happens, this will give me a better idea of what the fault is and when it happens instead of relying on what I have been told.

 

Once i have a better picture and i know what trips and when I can start testing stuff.

 

Assuming it has an unknown fault, is there any danger of damaging something in the house by connecting it up as it stands?

 

My fuse board is an old style Wylex and it used to have fuses when i first got in the house. Few years ago i replaced the fuses with this other type below. The picture is just an example, i replaced the old fuses with the same rating.

 

 

 

 

Not picking a fight but your OP said you'd already done that ......

Share this post


Link to post
Share on other sites
mecheng46

not in my house, i only saw the oven connected up in a different place.

 

I tested all the elements and they all seem fine. I am waiting for the food to be cooked on the old oven and i will stick this one in to give it a go.

Edited by mecheng46

Share this post


Link to post
Share on other sites
ProDave
Just now, mecheng46 said:

not in my house, i only saw the oven connected up in a different place.

 

I tested all the elements and they all seem fine. I am waiting for the food to be cooked on the old oven and i will stick this one in to give it a go.

So YOUR house probably does not have an RCD.  It may well run fine in your house.

 

If the owners house does have an rcd it may still trip there, so you may be no further forward.  Other than you can dry all the elements, so if it works in your house, run all the different functions to ensure every element has been heated up for a while.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

Terms of UseWe have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.