Dishwasher fault

[baggielad]

Was loading the dishwasher when there was a flash and bang from the hinge area. Checked consumer unit and the circuit breaker had tripped (32a), but not the RCD. Took off the back panel of the washer and discovered that a wiring loom was relatively tightly pressed against the edge of part of the internal metal frame of the washer. Over time they had rubbed against each other and eventually exposed a number of wires which I assume then shorted (see picture).

Untitled

• baggielad
• 24 May 2011
• 1

It’s clearly a design fault and would suggest a dangerous one at that, but I’m curious to know why the plug fuse did not blow (13a) or the RCD trip. I thought RCDs was designed to check against a earth leakage which I assumed would have happened here as surely the metal frame would have been earthed. Also, how dangerous is it?

Thanks for any replies

 

[ricicle]

If your RCD hasn't been mechanically tested with the test button for a long time then the mechanism could be 'sticky' which allowed the MCB to operate first. An MCB will operate with L to N or E faults as well as overloads
An MCB will almost always operate before a BS1362 fuse.

How old is the dishwasher ?

And I would consider getting your RCD tested by a professional, especially if the test button fails to operate it.

 

[nozspark]

I've had this happen twice on me a few years ago,, different dishwashers BTW

Cables at the bottom of the door were either fractured due to their constant bending (opening & closing door) or were rubbing on the framework!!

 

[ericmark]

Short answer speed. The magnetic part of the MCB likely worked faster than the RCD could act. The fuse is an odd beast. The 13A version is quite slow to blow, but in some cases we fit fuses as they are faster than a MCB.

However I would still test the RCD. One should use the special tester in order to measure time. But the mechanical test button built into RCD will normally highlight faults other than faulty build of label which would have been found when it was fitted.

Do check size. 100ma - 300ma RCD is used with a TT supply to protect against fire. But in a modern house we use a 30ma to protect personal. But the 30ma does trip easy so common practice is to use more than one RCD in a house. The more RCD's used the less they are likely to trip for no reason. Hence the move to RCBO's which build the RCD inside the MCB.

 

[baggielad]

Thanks for all the replies.

How old is the dishwasher ?

And I would consider getting your RCD tested by a professional, especially if the test button fails to operate it.

This dishwasher is only 3 years old.

The consumer unit was new about 14 months ago. I have tested the RCD and it tripped as soon as I pressed the test button. It's an 80a 30mA one.

I have reported this to the supplier Kenwood (Currys) and they are arranging for it to be inspected although it's outside of guarantee.

 

[riveralt]

This dishwasher is only 3 years old.
I have reported this to the supplier Kenwood (Currys) and they are arranging for it to be inspected although it's outside of guarantee.

This should still be dealt with under the Sale of Goods Act even if outside the guarantee period because of the 'fit for purpose' definition - which gives you protection for up to six years.

The burden of proof shifts from the supplier to the customer over this period but if there is obviously a design flaw then the burden will fall squarely on the manufacturer. They have the option to either replace the dishwasher or repair it.

 

[radioredcat]

This dishwasher is only 3 years old.
I have reported this to the supplier Kenwood (Currys) and they are arranging for it to be inspected although it's outside of guarantee.

This should still be dealt with under the Sale of Goods Act even if outside the guarantee period because of the 'fit for purpose' definition - which gives you protection for up to six years.

The burden of proof shifts from the supplier to the customer over this period but if there is obviously a design flaw then the burden will fall squarely on the manufacturer. They have the option to either replace the dishwasher or repair it.

And recall the others out there as a fault like that is unforgivable and the that fault has been there since new.

Andy

 

[Steve]

My mums dishwasher did this. Only the fault manifested itself as smoke billowing up the front of the D/W as it was mid-program. I have always thought it was a bad idea to have all that electronic kit in the door.

 

[Adam_151]

Its more worrying when you wake up in the morning and see black lines up the front of the control panel of the dishwasher and it eventually transpires that the spade connection to the power switch had overheated and started burning up, which only stopped when it melted enough to be above to contact the metallic inner door of the dw, blowing a small hole in it and taking out the 13A plugtop fuse. 30A re-wireable back at the board never even noticed