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Over the weekend the earth wire was inadvertently disconnected from the supply to the dishwasher. In this state the door is live (approx 120v). I have restored the earth connection and the door is no longer live.
This isn’t normal is it? There’s no measurable short across Earth/Live or Earth Neutral pins on the plug which confuses me. And why 120v, not 240? The dishwasher is a Siemens model and should still be under guarantee, am I right in asking for a warranty check? Any other advice?
Thanks
Nick
Re: Dishwasher door live
Nick,
Quite the normal for you to have experienced this after your earth supply was disconnected. The reason is that the ‘mains filter’ ( a suppression device attached to the incoming terminal point within the machine) is grounded to earth through capacitance both to the live and neutral supply.
For you to note a 120 volt reading on the door or any suitable earthing point throughout the machine, would be the inevitable consquence of this.
In the trade we learn right from the beginning that THE most important connection in an AC fed electrical circuit is the EARTH.
I’m pleased you realised the problem when you did and sorted it 🙂 Perhaps it also would be advisable for Siemens to check your machine out fully for you, if only for piece of mind 😉
Martin
Re: Dishwasher door live
I’m assuming the loss of earth was at the socket, in which case this would be an installation fault and not a manufacturing defect.
It would be up to the engineer (or manager) but you MAY incur a charge even if it’s within the warrant period. 😯Re: Dishwasher door live
Martin
Is this true for all appliances with ‘noisy’ motors? Washing machines, vacuums etc. I thought that the Earth was a secondary safety; I’m not saying it’s not important, but I thought that appliances cases should be free from voltage without an earth unless there was a fault.
BSH-MAN
Thanks. I realise that the lack of earth is an installation issue, but as I’ve set out above, I would not expect a voltage on the case unless there was a fault. It appears that this is misguided.
Nick
Re: Dishwasher door live
This is not surprising. Most filters fitted to domestic equipment have quite a high leakage current to earth. This is another good reason to ensure that domestic appliances are supplementary protected by an RCD via a split-load Consumer Unit.
Any device that contains a filter will have leakage cuurent, thus making the chassis ‘float’ to a voltage any where up to full mains voltage if the earth is diconnected or the leakage current on a filter should increase. 😉
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