Hi Fitzgordon

Electrical Circuits are different from country to country and this can look subtle, say 220V compared to 230V or 13A to 16A circuits, but can result in an increase in use of the capacity of the circuit by 20 or more percent, causing breaker trips in the new lower capacity circuit that would not occur in a more robust circuit with greater capacity. In a second explanation for breaker tripping, this may be a case of an espresso machine being well within the capacity of a circuit, but as many suggest a circuit breaker may trip when an appliance/machine has a component inside it that is either in the process of reaching 100% failure or that has failed. Component failure will cause a breaker to trip to protect the device and circuit from overheating and fires. If the second scenario, a failed component, is the case here (an not a circuit capacity issue), it appears our Original Poster ("OP"), Fitzgordon, has already begun brilliantly narrowing the fault location/component identity by disconnecting the Bezzera's pump and heating element. High-end espresso machines may differ from common mass produced appliances . . . they are often much more highly engineered machines and this might present some differences in electrical current needs as Fitzgordon and those responding have identified. Certainly Bezzera espresso machines are highly engineered with very precise specifications involved in their manufacturing, functional logic and operation.

Some Questions to consider:

• What are this Bezzera's power specifications? (How many Watts etc.)
• What type of Plug is on the machine (E, F, K type, photos always fun!) ?

Helpful and Fun possible additions for the OP:

• Any photos of this Bezzera Machine will be of good assistance, possibly identifying the exact model? (people love pictures)
• Any photos or videos of the internals (from when you disconnected the pump and heating element perhaps).
• Finally, any photograph of the involved breaker that is tripping if that's accessible?

Comparison of Denmark and Hong Kong AC Voltages, Frequencies, and Circuit/Plug-Types

1. Denmark
   1. Single-phase voltage (volts): 230 V
   2. Frequency (hertz): 50 Hz
   3. Plug type:
      1. C (2.5 A, not grounded)
      2. E (16 A, grounded)
      3. F (16 A, grounded)
      4. K (16 A, grounded)
2. Hong Kong
   1. Single-phase voltage (volts): 220 V
   2. Frequency (hertz): 50 Hz
   3. Plug type:
      1. G (13 A, grounded)

As bean74 mentioned brilliantly above (a fantastic read!), there are important considerations relating to sockets and circuits by comparison from Denmark to Hong Kong. While 220V and 230V may look similar and generally be suggested as interchangeable, due to the difference in circuits between Denmark and Hong Kong (16 A versus 13 A), a Denmark appliance may be closer to overloading a circuit in Hong Kong.

Ratings:
Appliances and espresso machines have a specific Rating. This can be shown in Watts. It's possible to represent Wattage in Amperage by dividing Watts by Voltage. For example, an Exobar Brewtus IV might have a wattage rating of 2000 Watts, and a Denmark home might use 230 V, dividing 2000 Watts by 230 V gives you 8.70 Amps. But also remember that the Denmark E, F and K Plug Types are 16 A and this likely indicates a 16A circuit . . . meaning . . . that such a 2000 Watt machine would push the Circuit to just a bit more than 50% of its capacity.

• The Denmark Math looks like: (2000W÷230V) ÷ 16A = 0.54 (54%) Circuit Capacity.

Now consider the 13A G Plug Types in Hong Kong. They are likely indicating a 13 Amp circuit and combined with the 220V Hong Kong voltages (instead of Denmark's 230V), the math suddenly jumps that 50% Denmark use of circuit capacity way up to 70%, still within range but pushing the limits of the circuit capacity harder for sure.

• Here's the math for Hong Kong on a Brewtus IV: (2000W÷220V) ÷ 13A = 0.70 (70%) Circuit Capacity.

Such a Rating can be important as it may provide guidance on the kind of Circuit to consider using, which can perhaps affect the Rating of the Outlet.

In the case of a 13 A Socket, it is very possible the Circuit could be 13 or so Amps, and it's worth considering keeping the Socket's Amperage from over-taxing the Circuit's Amperage. In the case of Hong Kong's G type plugs, this could mean the Circuit is 13 to 15 or so Amps. How this will affect a Bezzera's upper tier technologies and engineering is yet to be determined based on any forthcoming provided specifications/model etc.

Verifying Circuit Amperage/Plug-Type-Ratings:
Amperages on Plug Types ("G" in Hong Kong is for 13A, and in Denmark its E, F and K 16A) can indicate the Circuit's Amperage. Circuit Amperage is worth noting carefully since if an espresso machine's Amperage exceeds (or is regularly close to) the Circuit's Amperage Capacity (80% max rating safely), there will be regular, perhaps persistent tripping of a Breaker (a good thing as it protects your machine's components and the human's near the Circuit from possible fires). Definitely Fitzgordon's mention of possible dangers is well founded as a Breaker failure can result in escalation of the failure in the circuit, which could lead to a fire in a runaway uncontrolled circuit.

Voltage is important:
Using the Brewtus IV, as an example again, a machine with 2000 Watt specifications, on the Hong Kong 220V power supply in the 13Amp "G-Type" plugs/circuits is different than on the 230V of the 16Amp Denmark E, F an K (unlikely that 2.5A C-type used) plug/circuits. Suddenly the 8.7 Amps in Denmark's higher capacity 16A circuits becomes 9.09 Amps in Hong Kong's less robust 13A circuits. If the nominal safe and usable capacity for a Circuit is defined as 80%, then in Hong Kong, the amount a 2000 Watt espresso machine will use on a 220V Single-phase (volts) 13 Amp Circuit will be 70% compared to the 54% of Circuit Capacity being utilized in Denmark's 230V 16 Amp system. While a 2000 Watt Brewtus IV can work in a 13 Amp system, its closing in on that 80% of the Circuit Capacity considered safe to avoid Breaker Tripping and spontaneous espresso machine combustion.

Anyway, that's a few ideas and there are some very brilliant posters already in here above in the comments by bean74, dyno, Giampiero, homeburrero, Marcelnl! Hopefully this adds some extra info. Its going to be interesting to see what Fitzgordon discovers further! Fascinating post by Fitzgordon and the other commenters above that will definitely benefit many!