Duet 3 keeps blowing the breakers in my house when powered on!!!

[dc42]

What breakers are blowing: current limit breakers, or RCD (aka GFCI) breakers?

I had a problem last year that the master RCD breaker in the consumer unit would trip whenever I turned on the laser printer in my office. Suspecting a faulty class Y capacitor (the ones between mains input and ground that help suppress EMI), I replaced the Class Y capacitors in it. A little while later, the problem returned. Eventually I realised that it only occurred when both our new induction hob and several pieces of equipment in my office were turned on.

What was happening is that the leakage of the hob plus mains wiring capacitance plus the class Y capacitors in all my office equipment together created enough current between live and neutral to trip the 30mA RCD.

I fixed it by relocating the hob/cooker circuit to the non-RCD-protected side of the consumer unit, using a RCBO (combined current breaker and RCD) on that circuit instead of a plain current breaker.

I've since read that induction hobs are renowned for tripping RCDs. I guess they have larger class Y filtering capacitors than most other devices, because of the amount of EMI they would otherwise generate.

[Phaedrux]

@dc42 said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

RCD (aka GFCI) breakers?

Based on the photos earlier no, they look like standard north america breakers.

[A Former User]

Some of them were tagged GFI - does that refer to protected outlets in the circuit?

[dc42]

@Phaedrux said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

Based on the photos earlier no, they look like standard north america breakers.

Here in the UK you can get RCBOs, which combine a current breaker with a RCD (aka GFCI). Might it be one of those?

EDIT: the ones with TEST buttons are RCBOs.

[whosrdaddy]

I had an instance with one of my printers where the IEC connector fuse would blow after 10 minutes.
At first I thought that the fuse had died, but after 2 additional fuses died, I replaced the fuse again and
monitored the printer while powered, at that moment I realized that the IEC connector was getting really hot!!! (It was a crappy chinese one, bought via Amazon). After replacing the connector with a better specimen, the problem was solved, for some reason there was a bad connection inside the connector causing sparks and resulting heat.

Long story short, check your IEC connector (and get one with a fuse)

[A Former User]

One of the IEC connects were questionable to say the least.

[dc42]

@eddygara said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

@bearer just removed the bed wiring all together, so no power is being drawn in from the bed. Breakers still blew. Again not sure what my issue could be?? So strange that this thing could be drawing that much power!

Here’s a pic of my breaker terminal if that help!

https://i.imgur.com/LV4RTOI.jpg

Which of those breakers trips?

[Phaedrux]

@bearer said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

Some of them were tagged GFI - does that refer to protected outlets in the circuit?

Yes. In North America any ground fault protection is typically present in the socket at the point of use rather than at the breaker.

[dc42]

@Phaedrux said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

@bearer said in Duet 3 keeps blowing the breakers in my house when powered on!!!:

Some of them were tagged GFI - does that refer to protected outlets in the circuit?

Yes. In North America any ground fault protection is present in the socket at the point of use rather than at the breaker.

Some of the breakers illustrated have TEST buttons. Those look like RCBOs (combined current breaker and GFCI) to me.

[Phaedrux]

@dc42 That could be.

[A Former User]

It doesn't make a whole lot of sense to have the full rated breaker current as the fault current without being able to see/hear/smell it to me.