Any electricians? Kitchen hob woes

Any electricians? Kitchen hob woes

Author
Discussion

GregK2

Original Poster:

1,660 posts

146 months

Tuesday 28th July 2015
quotequote all
We have developed an issue with our ceramic plated hob unit. It suddenly went off while in use, tripping the RCD.

No problem I thought, i'll just switch the RCD back to the on position, I think the hobs were turned off at this point but can't be 100% if i'm honest as I just called through to my GF to do it..anyway as I flipped the switch I saw a flash in the fusebox, accompanied by a bang.

Now I realise I should have switched the main power off before attempting to reset the tripped switch. Any idea's what i've damaged?

I can now reset the tripped switch, but as soon as i turn the switch on the kitchen wall for the hob power, it immediately trips it again without fail (no hob turned to on)

I understand the elements can be damaged from getting wet and cause issues like this, but it's tripping before I even turn a hob on making me second guess whether this would be the issue here.

Any insight welcome, i'm pretty much leaning toward replacing the appliance.

MajorProblem

4,700 posts

164 months

Tuesday 28th July 2015
quotequote all
Just isolate things to find the fault.

You e already proved the cable is good from disbox to switch so it has to be between the switch and the hob. The elements don't need to be on for it to trip.

Ganglandboss

8,307 posts

203 months

Wednesday 29th July 2015
quotequote all
Are you sure it's the RCD you have tripped?



The RCD is the double width one on the left and detects a leakage to earth by detecting an imbalance in the live and neutral conductors. The narrow ones on the right are MCBs and detect overcurrent / short circuit. Alternatively you may have an RCBO which is a combination of the two devices. It will be a single width unit, but will also have a test button.



Is there a cooker switch near the hob? What position is it in?

GregK2

Original Poster:

1,660 posts

146 months

Wednesday 29th July 2015
quotequote all
Sorry it's the MCB and RCBO that get tripped in that case.

Yes there are two switched on the wall in the kitchen, one for Oven, one for Hob. It's when I flick the Wall switch for the Hob that causes the trip. I've tried keeping the Oven wall switch off also but no change.

When it did first go, it took the oven out with it, but this came back on after a while.

Edited by GregK2 on Wednesday 29th July 10:46

Ganglandboss

8,307 posts

203 months

Wednesday 29th July 2015
quotequote all
If you turn the cooker switch off, can you reset the breaker then?

GregK2

Original Poster:

1,660 posts

146 months

Wednesday 29th July 2015
quotequote all
I've been switching the RCBO to Off, then putting the MCB Labelled Hob back to On and then putting the RCBO to On again. It will stay there until i use the wall switch again.

Ganglandboss

8,307 posts

203 months

Wednesday 29th July 2015
quotequote all
GregK2 said:
I've been switching the RCBO to Off, then putting the MCB Labelled Hob back to On and then putting the RCBO to On again. It will stay there until i use the wall switch again.
Okay. Your first post did not make it clear where you are turning it on and off. If power stays on whilst the local switch is off, that places the fault at the hob.

When you say RCBO, do you mean RCD? Is it the RCD that trips or the MCB?

GregK2

Original Poster:

1,660 posts

146 months

Wednesday 29th July 2015
quotequote all
I think I may need to get a pic up to accurately explain what the situation is. I'll get one up this eve which should make everything much clearer than me trying to explain! smile

Ganglandboss

8,307 posts

203 months

Wednesday 29th July 2015
quotequote all
That would be very useful. The usual culprit in cooker faults is a heater element. If the hob is off, the MCB should not trip as there is no way power can flow to the element (unless it is something more sinister). If there is a short between the element and earth, current could leak from neutral to earth and trip the RCD. As the neutral connection to the element is unswitched, the RCD would trip even with the hob switched off.

There are a few theories, but I'll shut up until you post the photo and we know what sort of fault we are dealing with.

Make and model of the hob would be useful too.

GregK2

Original Poster:

1,660 posts

146 months

Wednesday 29th July 2015
quotequote all
OK, here's the fusebox:






This is what happens when i reset everything and then turn the wall switch on


Wall Switch - undone to check wiring looked ok


Hob is an AEG 6439 E

CorradoTDI

1,461 posts

171 months

Wednesday 29th July 2015
quotequote all
The good news is that it's a separate circuit from the oven so you can upgrade to induction fairly easily!

Richie Slow

7,499 posts

164 months

Thursday 30th July 2015
quotequote all
Throw that awful hob away and buy a proper one!

Simpo Two

85,404 posts

265 months

Thursday 30th July 2015
quotequote all
CorradoTDI said:
upgrade to induction
yes

GregK2

Original Poster:

1,660 posts

146 months

Sunday 9th August 2015
quotequote all
Earth was bad from poor fitting of original hob. Nice new induction fitted now smile