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Post by hal on Sept 26, 2022 15:47:25 GMT 1
I know it has been covered before, but I did not make any notes..
Remind me please the possible causes of an ID (but not the mcb that it is protecting) AND the main EDF switch would trip together (swimming pool pump is the culprit)
- I hope it is not an indication of poor earth...
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Post by pcpa on Sept 26, 2022 17:40:26 GMT 1
More than 500ma of fault current, usually to earth.
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Post by robertarthur on Sept 26, 2022 18:08:06 GMT 1
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Post by hal on Sept 26, 2022 18:38:11 GMT 1
Yes that was a nightmare - and my worry is, and I must confess here, that despite my promise, I never had my earths checked - laziness and it all seemed good after the anode was replaced…
I will definitely call someone..
When you say ‘a fault to earth’ does this imply a poor rarth or a good earth!
This time it is the pool motor. It will not start, but there is no ‘burnt ‘ smell that one associates withotors that have given up the ghost. I cannot afford this down so bought a new one regardless
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Post by robertarthur on Sept 26, 2022 18:49:56 GMT 1
Hal. a fault current to earth can happen everywhere: touching not so good wiring in your bathroom, from your hands through your body to your feet and wet floor. You don't need an earth rod to produce a current to earth. Switch off the circuit to your pool and probably your ID and your DB (disjoncteur de branchement) will be happy to let the electrons flow.
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Post by pcpa on Sept 26, 2022 19:00:39 GMT 1
When you say ‘a fault to earth’ does this imply a poor rarth or a good earth! It means that somewhere in your wiring there is an earth leakage current, that is to say that for example 2.2kw of electricity is passing through your chauff eau heating element, 9.16 amps are travelling down the live wire to the element and 9.16 amps travelling back along the neutral wire, both the ID and the DD do not sense any differential current, what goes out in one direction (phase) comes back in the other (neutre) everything is in balance, no earth leakage = safe system = no tripping. Now if 30Ma were to be leaking to earth via a corroded heating element sheath there would be 9.163A going out on the phase but only 9.16 returning on the neutre, 30mA earth leakage = imbalance = ID tripping. You have more than 500ma of earth leakage so both the ID and the DD are tripping, in an ideal world the former would trip before the latter. I used the example of the chauff eau element as it was under suspicion last time and has recently been worked on, if its the pool pump then the 2.2kw would become say 750 watts but its irrelevant, its the earth leakage current which is causing the tripping. I would also be looking to disconnect all the redundant wiring to the HP/HC relay, if its been done properly then there will be a 2 amp disjoncteur marked asservissement or C.E. if its fitted you should switch it off, that is on the basis that you said you no longer have an HP/HC abonnement.
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Post by pcpa on Sept 26, 2022 19:08:50 GMT 1
I should add that any tripping of the main breaker should be a big red flag, it indicates that somewhere there is a leakage to earth of more than 500ma, this is enough to kill an elephant, not desirable in a rental property.
Hopefully your earthing system is in good order and the fault current will be safely dealt with and the ID/DD tripping before any metal casings etc can become an electrocution risk.
In your shoes where you dont have confidence in those doing the service contract for piece of mind I would buy a plug in socket and RCD tester from Amazon or Ebay which will tell you if any circuits are missing an earth, have live & neutrals transposed (probably 50% of them but no big deal) and test the operation of the ID's.
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Post by hal on Sept 27, 2022 7:30:52 GMT 1
You mention the word ‘condition’ which maybe I should have concentrated on from the start.
Pool pumps and other appliances fail, so I guess that, as you imply, my earthing must be good on the face of it to allow the switches to trip, yes? What would happen if a pool pump or water cylinder failed where the earthing was not good?
If I am correct, then I am happy the ID is doing its job - but why pull the main EDF switch down with it?
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Post by robertarthur on Sept 27, 2022 10:53:19 GMT 1
@ Hal, ad 1/ Conditions change sometimes, rodents testing the eatability of plastic cables. A soon as it starts to rain you will notice, not at flagrant délit. ad 2/ Flash back, two quotes from last year's topic (your leaking boiler): a/ The disjoncteur de branchement (DB) is available in two versions: standard and disjoncteur sélectif S. Why this S -type? It thinks a while before it decides to switch off your power supply: " Disjoncteur de branchement ou disjoncteur de tête, retardé de 40 millisecondes environ, permettant d’assurer la sélectivité avec des dispositifs différentiels haute sensibilité 30 mA placés en aval" (text of Promotelec). This might partially explain the not very perfect cooperation between your RCD of 30 mA and the DB of 500 mA. b/ If specialized measurement equipment available it is rather easy to check this out, takes one minute, does the ID in question react in time, and below 30 mA, see picture. The same instrument also tests the earth resistance, local loop test, also one minute affair, after a first check of the line conditions pushing the test button is enough. 3/ The intervention treshold current of such a sensitive electromechanical device as a RCD (ID) may change over time. Worst case scenario: your 30 mA device going up to 60 mA and at the same time a disjoncteur de branchement (DB) going down to 300 mA. Making it much easier for a sudden peak fault current to trigger both of them. 4/ Nuisance triggering. There are always very small currents going down to earth (insulation not perfect, modern power supplies, fridges etc.). They are cumulative. As long as they are under the radar they go undetected because they are below the 30 mA RCD treshold level, everybody happy. It is however not difficult to imagine that only a relatively small extra fault current can exceed this safety level and there you go. See also this article by Chauvin Arnoux.
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Post by pcpa on Sept 27, 2022 11:16:05 GMT 1
so I guess that, as you imply, my earthing must be good on the face of it to allow the switches to trip, yes? Not necesserally but probably. An appliance can be unearthed meaning absence of an earth conductor or a break in the earthing circuit but still pass a fault current via its casing to the ground, Mother Earth via its fixings or mountings or pipework leading to it or through the body of the rodent that is chewing through the wires, all of these will trip the ID at the safe threshold of 30ma. That both the 30ma ID and 500ma DD are tripping together means a very fast heavy current of 500ma passing to ground which is likely to be through the earthing circuit as any other resistive circuit to ground would trip the ID while the voltage was building. Don't take a risk though, buy a plug in socket and RCD tester, they are only something like €13 delivered, maybe less.
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Post by robertarthur on Sept 27, 2022 11:45:51 GMT 1
This one goes for about € 23, checks the presence of earth (not: its resistance!) and incorporates also a simple RCD tester (30 mA threshold current, not the 500 mA DB range, no speed measurement). Made by Chauvin Arnoux this testeur de prises CA 751, only earth presence, about the same price. Bonus: makes it much easier to use the test leads of your multimeter, because the obturateurs (child safety) of the modern sockets make them rather difficult to access.
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Post by pcpa on Sept 27, 2022 12:19:50 GMT 1
Thats the one.
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Post by hal on Sept 27, 2022 13:13:51 GMT 1
Good idea. First I must find someone to check the main earth. I am on it!
OK, so accepting that appiances fail and that I have no problem with this, what I do have issue with is that I have IDs spread all over the place - maybe too many even - to avoid a failure pulling the whole place down, how can I avoid the main EDF switch from tripping?
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Post by robertarthur on Sept 27, 2022 13:43:09 GMT 1
@ Hal, never too many IDs.....In hospitals the 10 mA ID (patient safety) is quite common, start counting. To prevent a minor incident in only one circuit switching off everything when protection devices are in series there is always the principle of selectivity between these devices, hence the gap between 30 mA and 500 mA devices. It is not an absolute guarantee, sometimes a sudden very high fault current can trigger more than one device in such a chain. In your case: check the main switch, it should be the S type, reacting after some thinking, is this worthwhile to react immediately. Next step: ask a friendly electrician to test the differential earth leakage mechanism of the main switch, should be around 500 mA after switching off every circuit to minimise the cumulative effect of their residual earth fault currents, ranging from a few mA to perhaps 15 mA per circuit. The EDF main switch (single phase) without the suffix S.
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Post by chrisell on Sept 29, 2022 16:29:13 GMT 1
Ermmm .... The pumps f*""ed ...fix it or buy a new one. If it's blowing the EDF box it's pretty much shorting to earth so it's properly ..... It could be wiring if a mouse got hungry or the pump but either way it's that circuit. The pump is the most likely
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