switchboard problem in phase - that jumps

[jepeto91]

Hello,

I have problems with my electrical panel.
I have a subscription to 18KW with 30A on my circuit breaker.

It is an installation from 20 years ago and the former owner with a carpenter's woodworking machine ... hence this three-phase

I balanced the phases and added RCDs that were missing from the installation.
As soon as I use the electric balloon or my new oven (it worked with the old one), the main circuit breaker 500 mA set to 30A ... blows.
The balloon was not grounded, I put it.

I tested the amperage on the phases and I am just above 16A when it jumps. I also have 16A on neutral at that time.



Where is the problem ? I no longer know where to look.
Thanks for your help ... my last hope before calling an electrician.

[deceitful]

Is there an energy manager in Zone and load shedding on this electrical network?

[elephant]

Well, apparently you have already had the experience of lowering all the divisional units, then raising them 1 to 1, since you have come to the first conclusions.

Need refining: disconnect the devices then put them back on the circuit. Optionally, with an extension cable, fetch the current on another circuit.

If it continues under these circumstances, there is no photo: there is a fault in the insulation in your devices.

[Forhorse]

If the installation is old, it is not certain that the differentiation of the neutrals is made.
At the time, the neutral was neither protected nor cut.
For the installation well done there was simply a neutral bar at the bottom of the board from which all the neutral wires started.
In less well done installations, often a neutral wire was used for several circuits.
When we try to modernize such an installation, sometimes we have concerns ...

Now the strange thing is that only the main circuit breaker trips.
There would be an insulation problem on a device, the 30mA of the circuit concerned should react.
this is not guaranteed to 100% since I suppose that the main one is not selective, but still, it is always him who jumps and never the 30mA normally much more sensitive it is really bad luck .

[Grelinette]

At my place too there is a very old three-phase installation (40 years old! I will post a photo).

Apart from the phases which were unbalanced as and when the 4 homes were enlarged, I had 2 times failures that were difficult to identify:

1) an external outlet took the water and caused the general to trip randomly

2) more spectacular, breakdown that I also took a moment before finding: 2 mice had entered the table and had burned out between several contacts! ...

It is still unlikely that these are the same breakdowns at home ...

[i.dugra]

You may not have thought that, for ErDF and its overhead circuit breaker, 18KW in three phase means that you have to 6KW maximum on each phase! ...

According to your diagram, the 2 phases on 3 have their sum of the maximum loadings which, precisely, can exceed 6KW:

1 phase: 7,5 + 1,5 + 2 + 0,2 + 0,1 + 0,1 + 0,3 = 11,7 KW

2 phase: 1,6 + 1 + 0,1 + 0,2 + 0,1 + 0,1 + 1 = 4,1 KW

3 phase: 3,6 + 0,5 + 0,1 + 0,1 + 0,1 + 2,4 = 6,8 KW

So you must either better distribute the loads over phases or ask to switch to single-phase (it's far from being free!)

[raymon]

The simplest solution is to take a single-phase subscription if you have nothing in sorting. that's what I did at home and no more problems.

[i.dugra]

Corrigendum / Mail addendum 25 / 01 00: 02:

You may not have thought that, for ErDF and its overhead circuit breaker, 18KW in three phase means that you are entitled to maximum 6KW and simultaneously on each phase! ...

... ie 30 Amps maximum (to 2 or 3 amps close!) on each of them, whatever the time of day.

For the 1 phase, for example, only your induction plate at full power, all alone, is capable of saturating said phase! ...

To really see what is going on, the preferred tool to use is a Clamp that is placed at the top and around the phase to be examined.

Finally, note that eventually, it is entirely possible to turn the three-phase motor of your woodworking machine with a single phase ... Yep! ... but on condition that you do not ask too much of it ... And that is a whole different story! ... outside of the problem that you posed ...