Oven tripping RCD

[anyone8542]

Hi,

I have a 4KW Double oven which has started tripping the RCD when both ovens have been switched on for about 5 mins.

Any ideas why this could be happening???

Thanks

 

[securespark]

Sure it's just when both are on? That sounds like an overload.

What device is protecting the circuit?

Is it an RCBO?

Is it 16A?

If you turn Oven A on does it trip?

Now leave oven A on for 30 minutes.

Does it trip?

Let Oven A cool down.

Now turn on Oven B.

Does it trip?

Leave oven B on for 30 minutes.

Does it trip?

 

[Taylortwocities]

What exactly is tripping?

RCD
RCBO
MCB

Each is a different device. This pic may help you identify.

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

Then come back and clarify the info in your post.

Thanks.

 

[anyone8542]

Right been doing some testing as per second post
Oven A on @ 180C for 30 mins no problem
Oven B on @ 180C for 30 mins no problem

Both ovens on @ same time @ 180C
after 5-6mins RCD trips
Allowed oven to cool between tests

Just to confirm what's tripping here's a picture

Untitled

• anyone8542
• 21 Jun 2012
• 1

The thing with the yellow test button tripps.

Also can anyone confirm if this a 17th edition consumer unit??

 

[PrenticeBoyofDerry]

Sounds like the combination of earth leakage of both elements on the oven are adding up to enough to take the RCD out.
Name and model of cooker?
How long have you had it? if still under warranty call the service line!

 

[Taylortwocities]

Also can anyone confirm if this a 17th edition consumer unit??

There is no such thing as "a 17th edition consumer unit". Its a misnomer that marketing people are using.
You'll also find there are 17th Edition Testers on the market - again, there is no such thing.

Its the installation that might comply with the 17th edition of the wiring regulations. Compliance with the regulations may include how the consumer unit is made up, but other factors are in place including methods and types of wiring.

 

[securespark]

It would be nice to eliminate the RCD from the equation.

 

[pompeygit]

It would be nice to eliminate the RCD from the equation.

Easy to assume the RCD is faultless. 3 months ago had an RCD that was tripping every hour or so. It was on a new board that had only been installed for a matter of weeks and had been tested.

It tripped on both 1/2 times tests, so yes RCD's do fail

 

[bernardgreen]

The fault might be a neutral to CPC fault on a different circuit and the current taken by both ovens being on is high enough to cause the divided neutral current being high enough to trip the RCD

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

With dead short fault the divided currents are about equal ( depending on the ratio of impedance of the two paths, neutral and CPC ) so a 60 mA load will result in 30 mA difference through the sensor. The 60 mA load divides equally with 30 mA by passing the RCD sensor and 30 mA returning through the sensor on the Neutral. The sensor has 60 mA on Live and only 30 mA on Neutral so trips.

With any resistance in the fault the divided currents will not be equal and the current by passing the RCD sensor will be very small compared to the current returning through the sensor on the Neutral. The ratio of impedances will determine the load current required to create a 30 mA current in the by pass.