Kitchen Ring earth fault?

[Ross1]

Hi guys,

Customer woke up this morning with the Main switch/RCD tripped. He narrowed the problem down to the kitcken ring so He unplugged all the counter top appliances and switched all the big under counter appliances off at the switches.

I got there and turned the mcb on then plugged the toaster in first and the RCD tripped. I then punplugged the toaster and reset the RCD. I then plugged everything in the kitchen in One by one and left each appliance plugged in individually for 5 - 10 mins each, the only thing that that tripped the RCD was when I plugged the freezer in.

I checked the wiring behind each socket and all was ok. So I plugged everything in except for the freezer and the RCD didnt trip. I waited for nearly an hour and no trip even with the toaster plugged in and the switch turned on.

I didnt have any test equipment on me but I`m going back tmrw with test equipment, so my question is can anybody advise on possibley the quickest way to iddentify the cause of the fault?

Thanks

 

[mattmoo1974]

Like for Like you dont have to issue a MWC?

 

[telectrix]

correct.

 

[LlandrilloSpark]

A little earth leakage clampmeter would come in handy here, clamp on the earth of the ring then operate each appliance one by one and monitor the earth leakage, or you could switch the appliances in one by one and monitoring the leakage as you go, and see if it is anywhere near the RCD tripping current, which is very rarely 30mA, Ive had an RCBO trip at 21 this week

 

[Knobhead]

No wonder I suffer with depression!

No test equipment!
The freezers screaming at you!

For gods sake take up gardening!

 

[LlandrilloSpark]

fridges, freezers and cookers are well known leakers of current to earth

 

[richy3333]

Are some sparks are above BS7671?

Page 336

...'This certificate (Minor works) may also be used for the replacement of equipment such as accessories or luminaire,'...

Nuff said me thinks, as whoever wrote the Regs clearly thought different about when to use the MW certificate

 

[telectrix]

the key word is " may " it don't say " must "

 

[robsparky1975]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^agree^^^^^^^^^^^^^^^^^^^^

wait for the 2nd ammendment in a couple of years and then it will be a MUST.

 

[kathwilcox]

please don't say that think i/we all have enough paperwork to do as it is, anymore paperwork and i my aswell have trained to be a secetery not a spark.

 

[richy3333]

Hi Tel'

Sorry, but I can't agree with you there mate.

As you haven't been more specific I presume you are referring to 631.3 when you refer to the word 'may'?

631.3 Where minor electrical installation work does not include the provision of a new circuit, a Minor Electrical Installation Works Certificate, based upon the model given in Appendix 6, may be provided for each circuit altered or extended as an alternative to an Electrical Installation Certificate.'

The devil is in detail of the grammar? This section does not give an electrician permission to obviate the requirement to provide a certificate? The paragraph doesn't say ... a certificate may be provided...' i.e. complete a certificate if you feel there is a need to do so, otherwise don't? So to the question that the next amendment might change the word 'may' for 'must' - I doubt that would happen so specifically because it would change/alter the context of the paragraph and in any event there is already a requirement to supply certification for work completed by way of one of the 3 certificates detailed in BS7671. Personally I cant understand people bemoaning about completing certs - it's part of an electricians job, a necessary evil, just something that has to be done.

This section uses the word 'may' to offer an alternative to an electrician to use a MW cert rather than a full EI cert.

I would suggest that some electricians could chosen to read this section as they see fit rather than having due consideration for the correct punctuation.

Page 148 of the Onsite-guide also states when a MW cert should be used. Nowhere does it say that the use of the MW cert (or any other cert) is optional as part of our job.

Page 19 of the Onsite-guide for the Building Regs (England & Wales) says that when undertaking minor works a MW cert should be issued, or where work is undertaken by a DIYer then compliance to the Building Regs can be shown by having an electrician insect, test and certify the work by way of a MW cert.

Page 79 of the NICEIC guide for Inspection, testing and certification states that 'BS7671 requires inspection and testing to be carried out, and appropiate certification to be issued,...'

Certificates also assist in providing defences under Reg 29 of EAW Regs.

If anyone can show me where in BS7671 it says specifically that certification is optional then I am happy to change my view...

Back to the thread...

I would support the comments that you should undertake the IR tests and then put an earth leakage clamp meter on the appliance as it sounds as though this is at fault.

 

[dagrat]

631.3 Where minor electrical installation work does not include the provision of a new circuit, a Minor Electrical Installation Works Certificate, based upon the model given in Appendix 6, may be provided for each circuit altered or extended as an alternative to an Electrical Installation Certificate.'



sorry I agree with telectrix here, as replacing a fitting is not altering or extending a circuit, which I beleive is what the reg is refering to.

 

[ezzzekiel]

Carrying out like for like replacement does not require any certificate, sometimes you need to apply common sense

 

[telectrix]

the other thing to note is the MWC itself asks for "details of the modified circuit". replacing a fitting /accessory is not modifying the circuit. therefore, IMO, no certificate is required (although i do not dispute the idea that it may be advantageous to complete a test of the circuit and issue a MW

edit:sorry, double post.

 

[telectrix]

the other thing to note is the MWC itself asks for "details of the modified circuit". replacing a fitting /accessory is not modifying the circuit. therefore, IMO, no certificate is required (although i do not dispute the idea that it may be advantageous to complete a test of the circuit and issue a MWC). a like for like replacement can be carried out by any householder without any paperwork whatsoever.

 

[robsparky1975]

agree with tel,otherwise the diy sheds could not sell any electrical accessories as the diy bloke couldnt change a socket without having to call someone out to test and inspect/issue a mwc.