RCD Tripping

[Sidonio Costa]

Hi Everyone,

just looking for any feedback on this:

i have an Clipsal Powerguard CR8030 80A 30mA that keeps tripping. When the washing machine is on (new), or when the dishwasher is on (new), or when the electric over is on (new), or when using any of the kitchen wall sockets with any appliance ( 1600W+ kettle / toaster...). The thing is, this doesn't happen all the times! Some times i can use any of the above for weeks and it doesn't trip, unless i use more than one appliance!

Bearing in mind that my electrical skills are .... err... 0 ..... what do you advise?! should I change to an 100mA RCD?!

Thank You.

 

[Risteard]

should I change to an 100mA RCD?!

No. Of course you shouldn't.

Phone an Electrician.

 

[EFLImpudence]

what do you advise?! should I change to an 100mA RCD?!

NO

It's a safety device

Correct the fault.

 

[Spark123]

There is possibly a short between neutral and earth on one of your RCD protected circuits or an appliance has become faulty.
Any appliance which has a highish current draw causes it to trip.
Try unplugging everything and plug them back in one at a time to see if one item causes it to trip.

 

[JohnW2]

Try unplugging everything and plug them back in one at a time to see if one item causes it to trip.

Indeed - but, unfortunately, this is one of those cases in which that could be a very long/slow process ....

Some times i can use any of the above for weeks and it doesn't trip ...

Kind Regards, John

 

[securespark]

I always used to advise customers to unplug or switch off ALL their appliances apart from the CH/ HW, fridges, freezers and alarm system.

When you need to use an appliance, I would explain, plug it in or switch it on then disconnect it the moment you have finished with it.

After staring at me in horror for a good few moments, they usually understood the idea behind the plan.

 

[bernardgreen]

There is possibly a short between neutral and earth on one of your RCD protected circuits or an appliance has become faulty.
Any appliance which has a highish current draw causes it to trip.
Try unplugging everything and plug them back in one at a time to see if one item causes it to trip.

Very often an RCD will trip whenever the load is above a certain value ( kWatts ) irrespective of what item is used to create that load. This create confusion ands misleads one as to where the fault is. Trning OFF the MCB on the circuit with the fault will NOT stop the fault tripping the RCD when a load is switched on on a different circuit. This falesly suggests the fault is on the circuit supplying the load.

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

With a dead short fault Neutral to Earth a small load (such as a lamp) on the other circuit will trip the RCD, with a resistive fault such as water in a lamp fitting a much larger load (such as a kettle or electric heater) will be needed to trip the RCD

The only accurate way to identify the location of the fault is by disconnecting both Live and Neutral in the consumer unit and carrying out insulation resistance testing on every circuit.

 

[JohnW2]

<bernard's famous 'NE fault' diagram>

Bernard, I wonder if there might be a case for putting that diagram into the wiki and linking to it when necessary? ... you appear to have included it in posts (at least) 53 times.

Kind Regards, John

 

[Spark123]

I didn't say turn off any MCBs, just unplug everything. Turning off doesn't always isolate the neutral hence unpluging is the best bet. I'm pretty sure if you had a faulty appliance causing the RCD to trip you could figure it out without calling an electrician out.

 

[bernardgreen]

When the washing machine is on (new), or when the dishwasher is on (new), or when the electric over is on (new), or when using any of the kitchen wall sockets with any appliance ( 1600W+ kettle / toaster...).

I'm pretty sure if you had a faulty appliance causing the RCD to trip you could figure it out without calling an electrician out.

It seems that the RCD trips irrespective of which appliance is in use. Suggesting that it is not related to an appliance but to the amount of load on a circuit protected by the RCD.

Hence the assumption that due to a Neutral to Earth fault a fraction of the load's Neutral current is not going through the RCD's sensor and thus Live and Neutral currents through the sensor are not equal. When the load is large enough that the fraction of Neutral current not going through the RCD is more than 30 mA then the difference between Live and Neutral currents in the sensor will cause the RCD to trip.

 

[Sidonio Costa]

When the washing machine is on (new), or when the dishwasher is on (new), or when the electric over is on (new), or when using any of the kitchen wall sockets with any appliance ( 1600W+ kettle / toaster...).

I'm pretty sure if you had a faulty appliance causing the RCD to trip you could figure it out without calling an electrician out.

It seems that the RCD trips irrespective of which appliance is in use. Suggesting that it is not related to an appliance but to the amount of load on a circuit protected by the RCD.

Hence the assumption that due to a Neutral to Earth fault a fraction of the load's Neutral current is not going through the RCD's sensor and thus Live and Neutral currents through the sensor are not equal. When the load is large enough that the fraction of Neutral current not going through the RCD is more than 30 mA then the difference between Live and Neutral currents in the sensor will cause the RCD to trip.

Thats correct, the issue are not the appliances . regardless of which appliance i use the RCD will trip! but as i said previously this doesnt happens all the times!!

 

[deadshort]

Hi, you need an electrician with test equipment to test the kitchen socket circuit for a fault and also a ramp test on the rcd.

Regards,

DS

 

[bernardgreen]

Hi, you need an electrician with test equipment to test the kitchen socket circuit for a fault and also a ramp test on the rcd.

He will need to test ALL circuits, the fault may not be on the kitchen socket circuit. It could be on any of the circuits protected by the RCD. It could be damp in an outside lamp that is providing the route for some of the Neutral current from the kitchen sockets to by pass the RCD sensor.

 

[crystal ball]

Have look at all the circuits fed from the RCD side, I had a similar problem of intermittent tripping when the fridge was plugged in, the fault was in the shower

 

[ericmark]

As it happens same fault in my own house last night, tried the standard leaving off non essential trips, but it seemed I would need to break out the insulation tester in the morning and investigate further. In morning fault gone. Not the first time this has happened in the 20 years of having RCD protection on all circuits this has happened many times.