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George-Allsorts
George-Allsorts, Senior Appliance Technicial Manager
Category: Appliance
Satisfied Customers: 1448
Experience:  A whitegoods technician with 30+ years service in Domestic Appliance Service & Repair, and General Mechanical & Electrical Repair
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New bosch hob tripping RCD 70V between case and earth if you

Resolved Question:

New bosch hob tripping RCD 70V between case and earth if you disconnect the earth on the hob and test between the two

Submitted: 2 years ago.
Category: Appliance
Expert:  George-Allsorts replied 2 years ago.
Hello, my name is George..

Can you give the ENR of the appliance please.. It will be on a label underneath the hob.

Kindly be patient whilst awaiting any responses from me as I'm not constantly available.
Customer: replied 2 years ago.

Hi

ERN:PKE611D17E /01 FD9502

Regards

Darren

Expert:  George-Allsorts replied 2 years ago.
First port... Check that the earth is valid at the connection point at the wall
Customer: replied 2 years ago.

Earth has been tested I even tested the case (with earth disconnected) to the earth on the ring main at that showed the same voltage.

Live to earth 230v with the cable taken out of the hob and tested.

Expert:  George-Allsorts replied 2 years ago.
If you are sure that the earth in the ring main is good, and you have your wiring in the connector block correct, then return the product as fauty.
Customer: replied 2 years ago.

Hi Thanks

I am a qualified Electrician but not have done a lot with white goods, the Consumer unit has just been installed 17th edition with two rcd's just wondering if you came across this before.

Regards

Darren

Expert:  George-Allsorts replied 2 years ago.

Normally this would only happen if the interior earth on the appliance failed or if the earth circuit of the property was defective at the point of connection or further.

Problem is, if you open it up to check the earth and find a defective element or something else, you would have invalidated your warranty to get it repaired/replaced

Customer: replied 2 years ago.

Thanks every thing works ok ,washing machine ,dishwasher shower etc. just the hob trips it .Thanks for advice have been on some forums and this has happened before due to a RCD being installed .

Expert:  George-Allsorts replied 2 years ago.
The RCD being installed should not create this problem... Is there an explanation given for the theory?
Customer: replied 2 years ago.

all they say all other appliances may be eating into the tolerance of the RCD ...One even said the service engineer got a belt of a case (80V) on the case..

Expert:  George-Allsorts replied 2 years ago.
It doesn't sound like it is anything to do with the RCD to me.

The fault is an earth fault... There is no argument over that.. It sounds like the appliance is not earthed.

To me it sounds like the earth route to the consumer unit from the appliance is interupted.

Question: does the RCD trip when any other device is operated?
George-Allsorts and other Appliance Specialists are ready to help you
Customer: replied 2 years ago.

No only if the hob is connected..

Expert:  George-Allsorts replied 2 years ago.

If the hob is disconnected, you need to put an insulation tester on the feed cable to the appliance. Neg on earth, and live on both neutral and live together, or separately..
Something like a 500v megger would do the job

Let me know what readings you get