Combi Boiler reverse polarity

[Subby]

Hi sparks.
Gas safe plumber here please be gentle.
Just went to a boiler breakdown. I traced the fault to the room thermostat so I linked it out on the pcb board in the boiler.
The boiler is working fine now. 2 year old B&Q combi.

While I was there I checked with my multimeter the supply to the boiler and had earth to neutral 230v and earth to live 0v.
I was too paranoid to switch the neutral and live in case I blew the board.
Should I have switched them? How come the boiler is working fine like that? Will it damage anything being like that? If I need to reverse the polarity, then why?
Thanks in advance

 

[Andy-1960]

First thing I would do is check to see if it’s just the boiler that is connected up incorrectly or if the problem is back at the CU.

The boiler will work with a reversed L&N, but I think it should be checked out as if the reverse is in the CU, the live supply to all equipment in the property will be without any fused or MCB protection.

 

[Subby]

Thanks And just the answer I was looking for. I take it the MCBs only do the live and that's the issue with reversed polarity

 

[Strima]

If the full installation has reversed polarity there are serious safety implications as the MCBs will only switch off the neutral so the circuit will still be live.

This needs looking at and confirming ASAP.

Also would reverse polarity on a boiler not make things colder???

 

[Subby]

My god electricians have an awful sense of humour

 

[Octopus]

OP, you should add one of these to your tool bag - they are pretty good and would tell you at a glance if all is well - BUT they do not replace a proper test by a competent spark.

Kewtech Kewcheck 103 Socket Tester - https://www.screwfix.com/p/kewtech-kewcheck-103-socket-tester/45558?tc=AB5&ds_rl=1245250&gclid=EAIaIQobChMI3Zu8sKHB1wIVrZPtCh0BGwMOEAQYBCABEgKwofD_BwE&gclsrc=aw.ds&dclid=COTrwLKhwdcCFSOi7Qod91UDTA

Do you have a sparky "mate" you recommend to clients?

 

[Subby]

My Sparky mates will not fit in my tool bag and besides he charges too much for that service anyway

 

[Octopus]

Oops - I forgot the link!

Now added

 

[Octopus]

My Sparky mates will not fit in my tool bag and besides he charges too much for that service anyway

How much for what?

 

[The Ghost]

If I were at a site and found some kind of gas anomaly/problem I would advise the customer to get a gas safe person in. But then, I'm an electrician not a fitter.

 

[Subby]

That's just what I told the customer after reading Andy's reply, "call an electrician in to check the rest of the house" to only be told "I'm selling the house next year so I won't bother". Stinjy f**ker, and he's got 3 kids in the house.

 

[PEG]

There are several places,where the reversal could have occurred...would have been nice,to find out where,even if it was the leads to the multimeter

 

[Subby]

There are several places,where the reversal could have occurred...would have been nice,to find out where,even if it was the leads to the multimeter

Can't see how the leads on the multimeter would make a difference. I had 230v between neutral and earth, why would it matter where the leads were plugged in

 

[123]

You've done all you can, there is no helping some folk sadly

 

[PEG]

Can't see how the leads on the multimeter would make a difference. I had 230v between neutral and earth, why would it matter where the leads were plugged in

An analogy,would be if a ball-cock valve,were to be fitted,180 degrees out.

Definitely not having a pop at you,but you wouldn't be the first person to inadvertently place the meter leads in the wrong ports...i've done it,anyway.......so there,I'M Sparticus