How to Deal with a Power Tripper- clue, its not a politician!

Over the last few years we have all met some serious power trippers, but I meet more than most. Water and electricity are often an explosive mix and chances are you’re here because your coffee machine exploded or at least fizzed. So lets find out why and how?

Before I begin, I want to plug an en engineer gifted in communicating complicated stuff. I’m just going to quickly skim over the surface so at least we know the nature and extent of the problem, Dave Jones on his channel does a most excellent job on this topic in one of his best videos. ‘How not to explode your Oscilloscope”

So your coffee machine has tripped the power. What this means is it has tripped the RCD device in your fuse box. What is an RCD device?, it is the “Residual Current Device. This trips or switches off the power to your coffee machine rather quickly should current flow down the earth wire. You have to go and find the fuse box and reset it. And often if the coffee machine is still plugged in it trips again. Sometimes if the coffee machine element has cooled down or the leak has dried out, you get another crack at making a coffee and you put it down to gremlins. But sooner rather than later you call me.
So how did current get down the earth wire, well because a coffee machine being a high current device is “Mains Earth Connected”, that is all the metal parts of the machine are connected via earth wires back to the Mains Earth in your fuse box. And there is good reason for this, as it prevents you becoming the return to earth path should live current short to a part of the machine it shouldn’t. High voltages can gain connection to an earthed part of a coffee machine via a damaged or corroded component, often a coil or element, but more commonly a water leak.

So if you’re reading this chances are you have a water leak in your coffee machine or a damaged component. Now here’s the part you’ve been waiting for, the practical assistance with diagnosing the fault. If you leave your coffee machine to dry out, it can be a couple of days and turn it back on and everything seems ok. This is very typical of the Breville Dual Boilers, then it’s probably a water leak, although I have to state that heating elements in particular can leak to earth (not water, electricity) when they get hot. They are unpredictable. So usually the fact that a machine at least turns on after being left to dry out indicates you have a water leak. Water leaks of course provide a path for high voltage terminals like those on solenoid coils to find a path to earth.
If the machine trips the RCD as soon as the on switch is flicked then it’s a direct short probably an element and most likely the steam boiler element or the thermostat on the side corroded and providing an electrical path to earth.

Now I glossed over some important theory points above. Like why some appliances in your house only have 2 pins, these are not Mains Earthed, but rather isolated devices. These are class 2 devices and are double insulated with no metal parts and usually low current devices. This will be in the test as this is very important. Blow is a diagram I nicked demonstrating class one devices like coffee machines, that are wired to the RCD.

I also didnt talk about the ‘Neutral’ blue wire and ‘Mains Earth’ and what is the other earth, the so called cold earth? as opposed to hot earth or when you look at that picture above, the one I nicked, why is the Mains Earth connected to the neutral in the fuse box? Dave does above enough for us to be safe technicians.
I also didnt answer this question;

So how do we deal with these power trippers?

Firsly try and spot an obvious steam or water leak. This involves letting the machine dry out and then running it up and looking for the leak. In the Duel Boilers it’s pretty easy, usually they are venting from the water level probes like a Chernobyl Chimney right onto the triac board located conveniently right above.
You want to avoid constantly tripping the RCD, you can damage it. I use a Mega tester or insulation tester. This puts a high voltage at low current out, so I can connect the “live and Neutral” to the red and the earth to the black and send voltage into the machine. I can then eliminate one component at a time, yes cut the wire. When it stops burping oops beeping, it means it’s stopped leaking as I cut the right wire. It’s slightly more complicated that that. So try not to end up cutting every wire. You could just use your multimeter and look for the circuit between earth and live. Usually the short is the thermostat on the side of the steam boiler or an element. If I’m lucky its a coil. Often physical examination reveals damage to the component.

So that’s all I can think of to say about dealing with Power Trippers. I might post a video if I get time which is unlikely. I will also say that I have Breville Steam Boilers back in stock, both Gen 2 and Gen 3, Chances are you’re gonna need one. The Gen 2 Breville/Sage steam boiler is cost effective for repairing your old Duel Boiler