RCD trips when street lights come on, but ...

[MHF1995]

Hello everyone,

This is my first thread, and with English as a second language, I hope I can get you all trough my post without losing anybody.

So, as the title states - my current problem is as follows;

My neighbors just moved into their newly built house. One big house, separated into two separate homes, each with their own three-phase installation. Whereas each home has 3 consumer boxes, due to the possibility of renting out each floor as an individual flat.

The problem occurs, in both houses, exactly as the street lights come on, the RCD the main consumer box trips, including the RCD in the consumer box on the floors, where the AC units are running. Meaning, if the Aircondition units are running on the 2nd floor, but not on the ground and 1st, the main RCD will trip, along with the RCD on the 2nd floor - the two other RCD's will remain on.

The problem seems to only occur with the Airconditions's, as if they're all off by the time the street lamps go on, the RCD does not trip.

After the RCD has tripped, it is possible to flip the RCD back on, and it will not trip again for another 24 hours.

I have some theories regaring the RCD's being sensitive to harmonics coming from the airconditioners DC-inverters, but I am not entirely sure if this theory holds any grounds.

Any ideas?

Best regards,

Magnus Frederiksen

 

[Megawatt]

Hello everyone,

This is my first thread, and with English as a second language, I hope I can get you all trough my post without losing anybody.

So, as the title states - my current problem is as follows;

My neighbors just moved into their newly built house. One big house, separated into two separate homes, each with their own three-phase installation. Whereas each home has 3 consumer boxes, due to the possibility of renting out each floor as an individual flat.

The problem occurs, in both houses, exactly as the street lights come on, the RCD the main consumer box trips, including the RCD in the consumer box on the floors, where the AC units are running. Meaning, if the Aircondition units are running on the 2nd floor, but not on the ground and 1st, the main RCD will trip, along with the RCD on the 2nd floor - the two other RCD's will remain on.

The problem seems to only occur with the Airconditions's, as if they're all off by the time the street lamps go on, the RCD does not trip.

After the RCD has tripped, it is possible to flip the RCD back on, and it will not trip again for another 24 hours.

I have some theories regaring the RCD's being sensitive to harmonics coming from the airconditioners DC-inverters, but I am not entirely sure if this theory holds any grounds.

Any ideas?

Best regards,

Magnus Frederiksen

That is odd and never heard of that ever happening, wish I could help but there are mates on here that maybe help. Good luck

 

[James]

One of my neighbors used to have a similar problem when there other neighbour used there electric lawn mower. There problem was with N currents going down the neighbours earth spike.

 

[marconi]

What are the trip ratings for the RCDs? It will be a figure such as 30mA or 100mA.

Could you take a photo of the incomer and one floor's RCDs which shows all the symbols and lettering on them such as:



Is each consumer unit/circuit breaker board protected by just one RCD? If so, then before dusk at one floor's CU and with the AC running - but the other two ACs off - turn off all the other mcbs apart from the one for the AC and then see what happens when the street lamps turn.

Is your earthing by a copper rod with a thick green/yellow conductor?

Do the room lights dim when the street lights turn on?

Do you ever notice brightening of the room lamps?

I suspect an interaction between the electrical disturbances created when the street lamps turn on and the electromagnetic interference filters inside each of the ACs is causing a transient differential current (deltaLN) through the RCD and a brief transient current being 'dumped' to earth by the filter.

Once you have answered my questions I can recommend a fix for you which an electrician will need to carry out.

 

[telectrix]

MARCONI says it in a nutshell. all i can add is that your English is excellent, being a second language.

 

[DPG]

I agree with Tel - your English is better than many people on here. Hope you get the problem sorted. I dare say you will now that Marconi's interest has been awakened!

 

[MHF1995]

What are the trip ratings for the RCDs? It will be a figure such as 30mA or 100mA.

Could you take a photo of the incomer and one floor's RCDs which shows all the symbols and lettering on them such as:

View attachment 51703

Is each consumer unit/circuit breaker board protected by just one RCD? If so, then before dusk at one floor's CU and with the AC running - but the other two ACs off - turn off all the other mcbs apart from the one for the AC and then see what happens when the street lamps turn.

Is your earthing by a copper rod with a thick green/yellow conductor?

Do the room lights dim when the street lights turn on?

Do you ever notice brightening of the room lamps?

I suspect an interaction between the electrical disturbances created when the street lamps turn on and the electromagnetic interference filters inside each of the ACs is causing a transient differential current (deltaLN) through the RCD and a brief transient current being 'dumped' to earth by the filter.

Once you have answered my questions I can recommend a fix for you which an electrician will need to carry out.

First of all - thank you, everyone, for taking an interest and thank you, Marconi, for the in-depth answer! I will when I get a hold of my neighbor, carry out the tests at his place! It might be a day or two until I can, but I will bring an update ASAP!

 

[marconi]

MHF1995 - a few more items of information from you please:

1. What type of street lamps? If you don't know could you describe the colour of the light and if they flash before warming up to full brilliance.

2. Do the street lamps turn on together or is street lamp controlled by its own switching system?

3. Have the street lamps been recently replaced?

4. Are the street lamps the column type?

5. Do you ever feel a tingling sensation when touching metalwork, pipes, taps, metal electric appliances?

 

[static zap]

MHF1995 - a few more items of information from you please:
...
5. Do you ever feel a tingling sensation when touching metalwork, pipes, taps, metal electric appliances?

I'm thinking the other angle ,
(Tingling from the street lights -as they burst into life -take care ) --Untrustworthy Volt stick / Neon in the semi dark.!
(..And my favourite -have you watered you earth rod recently )
Are ALL the street lights working ?
(Do take care if they are hard to access)