RCBO main breaker problem

[Oiler1fan]

Being safety minded, I wanted to add RCBO's to some of my house circuits - washing machine, kitchen plugs, exterior plugs, water pump.  Our area is standard TNC-S with MEN but my sparky discovered that the house is wired with many shared neutrals so he could not install the RCBO's on three of the four circuits.  He said a problem he sees a lot.  Next best option was to install a 50A 2P main breaker RCBO which I had waiting for another project - but to do this he said he needed to remove the incoming neutral from the ground.  OK I said not really understanding the reason why, he just said to avoid nuisance trips.  All was good after circuit testing but now tonight I have three LED lamps that don't shut off completely, it's like they are on a very low dim.  Your expert guidance needed please ????????

[sometimewoodworker]

The guidance is that you do not have an electrician. 
 

An real electrician will be able to actually diagnose the wiring and isolate the circuits.

This is a very time consuming operation and rewiring could be cost effective option.

 

I defer to @Crossy to opine on the de-bonding the MEN link. I suspect that you may now be less safe than you were.

 

As an alternative to a complete rewire job, installing completely separate feed RCBOs for important circuits is a sensible alternative. 
 

Depending on your location I know an actual electrician who can do the job but it’s almost certainly going to cost tens of thousands to do the work. 

Edited August 4, 2022 by sometimewoodworker

[Oiler1fan]

Thanks for the feedback, yeah de-bonding the MEN link was a red flag, interested to hear @Crossy opinion on options.

[Crossy]

Yeah, borrowed neutrals are a major problem here ???? 

 

Anyway, where was your N-E bond before the incomer was replaced? If it was in the correct location (before the incoming breaker) you should be just fine to leave in place and your sparks is mistaken.

 

Your LEDs glowing when "off" is a bit worrying, can you verify that your incoming polarity is correct? Also check the voltage between neutral and earth of your now TT system. 

 

Maybe post a photo of your board with the lid off, a picture is worth many words.

[Oiler1fan]

The N-E bond was in the correct location before the incoming breaker, I verified that before the job started.  I'll check the N-E voltage and get a pic of the board this afternoon.

[Crossy]

10 minutes ago, Oiler1fan said:

The N-E bond was in the correct location before the incoming breaker, I verified that before the job started.  I'll check the N-E voltage and get a pic of the board this afternoon.

 

In that case there was no need to remove it, putting it back would be advisable, but do check your polarity first, just in case.

 

[Oiler1fan]

Forgot to mention the polarity is ok too, that was the first thing we checked.  Going to measure N-E and get a pic now.

[Oiler1fan]

OMG - the polarity on the main breaker is reversed and N-E is 226V ????

[Crossy]

4 minutes ago, Oiler1fan said:

OMG - the polarity on the main breaker is reversed and N-E is 226V ????

 

Ouch. Did your man disconnect at the meter when he did the work? If so it's sooooo easy to get the polarity swapped putting back the two black wires (I've put white tape on the neutral at the meter, just in case).

 

That would also explain the LEDs glowing.

[BritManToo]

18 minutes ago, Oiler1fan said:

OMG - the polarity on the main breaker is reversed and N-E is 226V ????

My house was like that when they first built it.

Never touch any wire without a tester screwdriver, saved my life the first day I moved in.

Went to wire in an electric shower heater, wire was live even with the shower fuse off.

Not much point having all your fuses wired to the neutral, and live running to all your sockets all the time. Not to mention wasting all that electricity heating up the earth around your earth rod.

 

Yep, I've also got a shared neutral ...... these guys are idiots.

Edited August 4, 2022 by BritManToo

[Oiler1fan]

Polarity at the meter is fine, they reversed it at the breaker as the final step.  They marked the Live with red tape at my instruction and then connected to Neutral.  He is on his way here now to fix it, we will also reinstall the N-E bond and check the RCBO operation, if a problem will put the standard breaker back.

[Oiler1fan]

Our PEA neutrals are white striped

 

[Crossy]

33 minutes ago, Oiler1fan said:

Our PEA neutrals are white striped

 

Yeah, a sensible sparks would disconnect at the outgoing side of the meter where the cables are both black.

 

And, I see you have that rare animal, seals on your meter ???? 

[Crossy]

34 minutes ago, Oiler1fan said:

Polarity at the meter is fine, they reversed it at the breaker as the final step.  They marked the Live with red tape at my instruction and then connected to Neutral.  He is on his way here now to fix it, we will also reinstall the N-E bond and check the RCBO operation, if a problem will put the standard breaker back.

 

Yeah, looking at your photo that's what they've done!

[Oiler1fan]

Normal service has been resumed, N-E bond restored and polarity corrected.  All circuits running fine with the 50A RCBO as you suggested it should.  Now to wait for darkness to fall to search for glowing LED's ????.  Appreciate the input from everyone for a fast solution ????????

[Oiler1fan]

[Oiler1fan]

Happy to report this morning that all is good ????????