Help me before I cook myself

Forums › Home Workshop DIY › Help me before I cook myself

1 | 2

richms

28187 posts

Uber Geek

Trusted

Lifetime subscriber

#2408373 28-Jan-2020 20:04

neb: Doesn't the RCD do that too, or is it a pure RCD function? I'm also not 100% certain that that's the actual problem, I went as far as I could without pulling apart the distribution panel but it could be something else. The symptoms are that with the RCD off there's no power, with the RCD on and the MCBs on or off, doesn't matter, there's power. The reason why I hadn't noticed it until now is that one of the three MCBs powers nothing I can identify (see "Casa de Cowboy"), the second is for a circuit that never gets turned off because there's a bunch of stuff that may get upset about power losses, and the third is for the kitchen with nothing very obvious that changes state when power is lost.

When its done the cheap way like that, the RCD is only doing RCD stuff, and then the 3 breakers after it (used to be no limit so you would see one RCD or 2 per house for all breakers) do the over current.

The A on the RCD is its maximum, nothing to do with overcurrent.

If you go for combined RCBOs, like you should do, it costs a little more but takes up less space, doesn't need the mess of neutral bars and means that half your stuff doesnt get turned off when the flatmate leaves his window open and a powerstrip on the windowsill.

Richard rich.ms

Bung

6486 posts

Uber Geek

Subscriber

#2409373 28-Jan-2020 20:43

Domestic RCD have to break active and neutral and I thought that it has only fairly recently been possible to do that reasonably with an RCBO that was a similar size to an RCB. At least I hope. Our version of Casa del Cowboy is a good example of the perils of the local professionals. I've picked an electrician to do some rework on the basis that he wouldn't have been around when it was done and not knowing who the previous owner had do the work I'd hate to pay the original by chance to do what he should have done at the start.

xpd

Geek @ Coastguard NZ
13767 posts

Uber Geek

Retired Mod

ID Verified

Trusted

Lifetime subscriber

#2409460 29-Jan-2020 08:32

The more I read your guys posts and think about things, the more it seems I will get a sparky in..... thinking about how a lot of the house was built, I don't know I'd trust the wiring to be totally up to code :D

Damn 80's "home handyman" attitude on a lot of stuff here. :)

Gavin / xpd / FastRaccoon / Geek of Coastguard New Zealand

LinkTree

Fred99

13684 posts

Uber Geek

#2409498 29-Jan-2020 09:47

neb:
richms:

neb: Not just why but who, the sparkie who wired up the distribution board somehow bypassed the MCBs so only the RCD that covers the three MCBs has a function. Sorting out what's wrong in the wiring would require poking round in the distribution board which is well above my pay grade, we need to get more wiring done when we do the big rebuild so I'm leaving it until then.

So there is potentially no over current protection on those circuits at the moment? Sounds like that "sparky" needs dobbing in to worksafe for doing a giant F up.

Doesn't the RCD do that too, or is it a pure RCD function?

If it does, it should be marked as an "RCBO" (the "O" for overcurrent protection), with current rating marked on the RCBO.

I have no idea about the legality of leaving MCBs on the board when they're no longer connected to any circuit - doesn't seem like a very good idea - especially and more-so if they're marked as if they're protecting circuits. Seems dangerous to me (not a sparky).

Bung

6486 posts

Uber Geek

Subscriber

#2409540 29-Jan-2020 10:26

It probably wasn't the intention to bypass the breakers just like it wasn't the intention of my neighbour's plumber to have his apprentice leave all the under house waste joints unglued. Maybe the electrician assumed a trainee knew what he was doing.

Employing professionals isn't a guarantee of a perfect job but at least you don't cop the blame personally.

Fred99

13684 posts

Uber Geek

#2409558 29-Jan-2020 10:56

Bung: It probably wasn't the intention to bypass the breakers just like it wasn't the intention of my neighbour's plumber to have his apprentice leave all the under house waste joints unglued. Maybe the electrician assumed a trainee knew what he was doing.

Employing professionals isn't a guarantee of a perfect job but at least you don't cop the blame personally.

I was on a job a few years back, there was a "sparky" on site, we didn't have our inverter for testing some gear and needed a circuit wired and livened up, he did it. I was talking to him, he knew my son (almost registered - should be sparky in a couple of months). Talk to my son when I get home, the "sparky" was an apprentice who'd just completed pre-trades at polytech and was being sent out on his own in a van to do basic - but restricted - work on his own. Put yourself in the apprentice's shoes - and what would you do? He was doing as he was told.

neb

11294 posts

Uber Geek

Trusted

Lifetime subscriber

#2409603 29-Jan-2020 12:24

Bung: It probably wasn't the intention to bypass the breakers just like it wasn't the intention of my neighbour's plumber to have his apprentice leave all the under house waste joints unglued. Maybe the electrician assumed a trainee knew what he was doing.

Employing professionals isn't a guarantee of a perfect job but at least you don't cop the blame personally.

It may not have been the electrician who did the panel but the cowboy wiring in the house. In other words he replaced the 1970s distribution board (ceramic breakers screwed onto hardboard) and assumed the wiring did what it was supposed to, when in fact it did God knows what once it left the board.

In terms of the quality of the work, it was top-notch, everything neatly lined up and clean, nothing to fault there, so I'd be just as willing to blame the existing cowboy wiring for the issue.

1 | 2