What to do when the differential does not reset. Example procedure.

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Sometimes we receive requests for help regarding differentials that “click” and never reset again. It can happen in new plants, but is more likely when the plant is several years old.

Each of us in the house, in the apartment, in the shop, but also in more complex structures has a switchboard or an electrical panel. In some cases there is a single general switchboard for everything, in other cases instead there are several switchboards or switchboards that supply electricity to some zones. Let’s see with an example to clarify the concept of how to identify the circuit that determines the fault, or at least carry out an initial verification before calling a professional: at least try.

Let’s consider a panel or switchboard where we have a differential switch and a series of circuit breakers. The differential trips and it is no longer possible to reset it, whether it is manual or with automatic reset: in the latter case, it either tries to reset a few times or gives a fault indication and does not reset again, then it proceeds as if it were a manual differential.

In normal operation, all switches are in the “ON” or “1” state, as in the following figure. In this case we have a type A 30mA circuit breaker, a series of circuit breakers alongside and which receive power from the differential.

At a certain point, suppose on a Saturday evening, perhaps during a dinner with friends at home, the differential is triggered. The hazard lights come on. We go and see, the differential is reset but it doesn’t “stay up”, it continues to shoot. What I do? Panic? Who do I call now? We are as in the following figure.

Then I try to do the following procedure.

I turn down all the circuit breakers.

First of all I just put the RCD on, if it stays active then do the following, if it doesn’t activate then it could be the RCD itself or some circuit that hasn’t been opened. In this case we recommend calling a professional.

Then I insert only the first magneto-thermal switch, then the differential and check if the latter doesn’t trip. I’m trying out the daytime lights circuit in this example.

Well, for example I see that the differential remains engaged, so the day light circuit is ok.

Now I proceed in the same way with the second circuit breaker and so on until I will probably find which one generates the fault.

I get to try the kitchen socket circuit, and I see that now the differential “triggers”. Maybe the problem is in the kitchen socket circuit? We leave this switch “off” and try the others as well to confirm.

Well, the others are “all up” and so is the differential. So almost certainly the problem lies in the kitchen socket circuit in the example, but in your case it could be any other circuit, such as external light, driveway gate, video door entry system, external sockets, laundry sockets, garage sockets, burglar alarm, video surveillance circuit, depending on how many circuits has your electrical system been divided into.

In this case, if the kitchen socket circuit has not been changed over the years and only makes the kitchen sockets, just try to disconnect all the appliances from the sockets and check if the differential resets, it could be due to some appliance for example (fridge, dishwasher , food processor, etc…) . You may find that the problem is simple, in which case you have found the fault and have not needed any help. Great.

Otherwise it could be complicated for a number of reasons, for example:

  • the plant has its own age.

  • Appliances have their age, but they’ve always worked well until today.

  • Perhaps I also had some lights under the wall units added to the socket circuit to do faster, I think the kitchen socket circuit also does something else but now I can’t remember.

  • I’ve done some things over the years, but I don’t remember anymore.

  • Maybe I have some water or humidity leaks in certain places.

  • Maybe I have some grips a little broken but I use it anyway as long as it goes.

Troubleshooting can become expensive in the sense that it may take some time to find the cause of the failure. If the circuit has remained consistent over the years, simple attempts are made first to eliminate simple causes. If not, you have to start from the circuit breaker that triggers the differential, check that it is not faulty, then you go on to examine the circuit that is powered by that circuit breaker, from the shunt boxes, etc… It all depends on how your system it has been divided, if the circuits over the years have remained faithful to what is written on the label on the panel (kitchen socket circuit only feeds the kitchen sockets, or something else as well).

We are well aware that a subdivided system with multiple differentials can cost you more, but it is important to bear in mind that, when we install a system, we probably know what the problems may be over time. For this reason we propose solutions that help you as much as possible to solve problems that will arise in the future on your own. Sometimes we are required to install just one socket circuit and one light circuit and nothing more, this is normal especially in small systems, but we always think that a good electrical system for one of our customers is like what we would do if it were our homewith our wealth of experience, for our family or for our company.

In this case our boys had to arm themselves with “holy” patience and find the fault.

Also here.

#Electrical system #Renovations #private #maintenance #industry #commercial

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