Three phase RCD tripping

[Davido]

Hi Folks,

I have a question about a property in Spain and its power supply

I think I have messed up with my electrical company and asked them to supply me with a lower potential than I require. The house did have a 12,000 KW supply, I asked for a night rate and in order to get this I had to opt for a different power connection either 10,000W or 6500W. I assumed that the 6500W would be per phase I am thinking now it is 6500W in total.

The day they changed the meter the oven started tripping the RCD, the hob also trips it.

Is it usual for an RCD to trip but not latch down just to trip the power? It can be reset by toggling the switch.

Would not having enough power in the one of the phases cause the RCD to trip?

The bumer is if I have to ask to get the higher 10,000W rate I will have to have the house certified again. Is there any way that all three phases can be used together to give me more power?

Thanks in advance

 

[cobrauk]

Rcds only trip on a earth fault, ovens are always doing this because of the elements could just be unlucky and it happen when it did ?

If you only have 6500w available then that's only about 30amps depending on your voltage ie 6500/230 = 28.26amps and if it was spread over 3phases then you will be in big trouble wouldn't you?

 

[Davido]

Thanks, what gets me is that the RCD does not fully trip, the button does not come all the way down. any clues ? Yip big trouble, that is why I posted here. The RCD also trips on the hottub and hob when it starts drawing around 12 amps. never noticed it on the oven or hob untill I bought a new element for the hot tub thinking that was the cause.

If RCDs only trip on earth faults being under supplied with power on a resistive load should not matter.

I shall call the company back that changed the meter just in case their is a fault there, I am wondering if they have programmed it correctly.

 

[Darkwood]

Some rcd's trip to mid position to allow you to tell its tripped and not been turned off, as said before they only look at earth leakage and i suspect one of the elements in the oven is showing early signs of failure... get an Electrician in to check this out, if it trips after a time of the oven been on the fault may not show if elements are tested cold it may be the case it only faults when the element is hot and slightly expanded.

 

[cobrauk]

Are you sure these are rcd's and not rcbos ? is this the main switch you are talking about or for one circuit ? did they fit it when doing this work ? give more details please

 

[Victor]

If you have a 12kw supply, this would be 4kw per phase as it is here in France. However if you have not balanced the various circuits equally between the phases and have one phase that is exceeding the 4kw limit, then the whole system will trip out.

 

[Engineer54]

That's one thing you guy's in UK don't have to worry about, you get up to 100A on DNO supplies for domestic installations straight off the bat so to speak. In most of Europe and a good few other countries, you pay different rates for different supply KW values. I wonder how many households in the UK could get by on a max 12 KW supply (espeacially over a 3 phase install) or less?? Not many, the dammed 10.8 KW showers would be a killer straight away!! lol!!

 

[WilcoxElec]

If you have a 12kw supply, this would be 4kw per phase as it is here in France. However if you have not balanced the various circuits equally between the phases and have one phase that is exceeding the 4kw limit, then the whole system will trip out.

--- so if you have 6500 kW that would be a setting of 10A per Phase. In France the setting in AMPERES is on the disjoncteur de branchment - I would have thought this would be the same in Spain.

 

[cobrauk]

only 10amps per phase that is very low isn't it ? in the UK the minimum is 60amps on a single phase to house holds

 

[Engineer54]

--- so if you have 6500 kW that would be a setting of 10A per Phase. In France the setting in AMPERES is on the disjoncteur de branchment - I would have thought this would be the same in Spain.

So what are the supply values/bands in France, that you get to choose from, for typical domestic installations??

 

[bertt]

Hi,

About power installed and your evaluation and RCD tripping.
Warning:
- The installed power capacity and maximum power absorbed simultaneously for any premises there are separate and different things.
- About RCD please take a picture for me if you don’t mind.
Probably burned actually.

Thank you.


bertt. :rolleyes2:

 

[Farmelectrics]

Don't they supply single phase supplies why have they given you a 3 phase supply

 

[RogertheBodger]

Davido - From the meager information you have given I am guessing that what has happened here is that when you contracted for your supply to be down-rated to 6500W, the power company has come along and fitted a new control circuit breaker which for your supply size would be a 10A TP&N (an ordinary circuit breaker, not an RCD) This is why your higher rated appliances are tripping, This circuit breaker (or ICP) is the way that they ensure you can only take the amount of current you are paying for and is perfectly normal in Spain.

You need to alter your contract with the supplier back to 12k (15A per phase) or even higher.

 

[Farmelectrics]

why 3 phase why cant they supply a single phase

 

[lyntonworcs]

What sort of property do you have in Spain? I have an apartment which is only single-phase and have no problem with regards loading other than when all the heaters and cooker is on, then it trips on overload rather than earth fault.
I'm not aware of many homes in Spain having 3-phase!

 

[Farmelectrics]

^^^^^^^^^^^^^ agree still waiting for a reason they cant give you a single phase supply

 

[bertt]

So, Who ..got the solution?

:gunsmilie:Man Fights Goose, With Lightsaber - YouTube

 

[RogertheBodger]

The size of the cable supplying a property could be the limiting factor, three phase into domestic properties is common and may well be supplied by 4 x 6mm cable, which would make a single phase supply a bit iffy, the cable could be upgraded but it may be more trouble than it's worth depending on length/difficulty etc.

Edit. OP's probably still in the queue at the electric company office, they're hard work to deal with.

 

[WilcoxElec]

So what are the supply values/bands in France, that you get to choose from, for typical domestic installations??

Puissance souscrite. (kVA)	Réglage Disjoncteur (A).
3	15
6	30
9	45
12	60
15	75
18	90
24	40
30	50
36	60

But this is not the whole story. Lower settings with 3 Phase unlikely - obviously :smile5: .

 

[WilcoxElec]

Often in this case the 4 wires are used as two pairs for monophase giving a total x-section of 12 mm2 - which would be counted as 10mm2 - at least temporarily

 

[WilcoxElec]

Three phase common in the countryside here in France - for agricultural use - pumps and so on. People often buy an old farmhouse and find they have 3 Phases - and usually the first thing they do is get it changed to mono - unless they are farmers and want to run motors and stuff ....... The disjoncteur de branchment is effectively an RCBO type "S" - which means it can be set to different sensibilities - but is sealed by the electricity supplier and can be set by an electrician contracted to do so by the supplier - but otherwise it is a criminal offence to break the seal -- I expect it is the same in Spain - from what I can make out here. A 12kVA three phase supply would probably be OK on three phase - 20 Amps per phase - provided the cookers and hotplates were appropriate and could be wired to more than one phase - which is often the case - (especially with induction). I always encourage customers with 3 phase to change to monophase unless there really is an electromechanical thing that is best with 3 phase ....... like a big irrigation pump !