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Posted By Topic: The Missing Link

Satobsat
Oct 18 2019 16:23

So I came across a switchboard yesterday that hasd no MEN link. When I cam to do my EFLI test at the SWB I got a measly 6A PEFC. Looking at the neutral bar and the way it has no empty tunnel connectors on it I'd say this board has never had an MEN link. It also has two RCDs which feed 5 MCBs each so it was done quite a while ago. The original boad was outside and still has the meters on it and a neutral bar and earth bar in the back with a link but only the main neutral is on it and the SWB neutral, there is no MEC to that bar or any other earth or bond wire, it is empty. There is an electrode and MEC to the indoor board and it is labelled as the MEC at either end. How on earth excuse the pun) did this get missed?
Anyway my question is do I need to get it inspected as there may have never been an MEN link, or can I just treat this as maintenance and replacement?

There was also two earth bars one bar had one PEC connected but the bars were not linked. I have pictures if any one is interested.
   

DougP
Oct 18 2019 20:57

Personally, I would have fixed it immediately.

It's potentially lethal the way it is. Certainly the circuits on RCDs might be slightly safer, but there's a good chance that the higher risk appliances like the hot water and stove, weren't on RCD.

As far as inspection being required - work on the MEN link other than just removing and replacing for testing, is "mains work" and requires inspection.

It's never a '"bad" idea to have a second person check and test the high risk work on an installation.
   

Satobsat
Oct 18 2019 21:19

Hi Doug, of course the first thing I did was install a link. My question is am I obliged to get it inspected? There clearly never was a link after the new electrode was installed and the MEN should have been switched from the old board to the new board. I'm happy with my EFLI test after I relocated the link. I think there could be issues with earth leakage tripping the RCDs if the current state of affairs is repeated through the house. That's if the PECs are up to spec. Before I see no real reason why they would operate, unless there wa a decent fault path. Same with a phase to earth fault, 6A isn't a lot especially if it's not a a short to earth only transient voltage. And that 6A was at the board pf the incoming main to the MEC.
   

Satobsat
Oct 18 2019 21:28

"unless there wa a decent fault path."
Should read "unless there wa a decent fault path to physical earth."
   

BCee1
Oct 18 2019 23:04

Have tried to find a previous discussion on this but it may have been under another heading. From memory the upshot was, yes very important to put the link back in to get the EFLI back to where it should be, but it is mains work and requires inspection.
   

Satobsat
Oct 18 2019 23:16

Customer is not going to like that, she has been ripped off by her brother in law that charged her almost $30 000 tor refurb an existing sleepout. On what grounds are you classing replacement of an MEN link as mains work?
   

DougP
Oct 19 2019 00:21

ESR 4 definition of "mains work" (in part)

(iii) work on the connection between earth and neutral made by the removable link within the MEN switchboard closest to the point of supply;
   

Satobsat
Oct 19 2019 10:05

I agree but we don't get an inspection everytime we remove and refit one for testing. If the link was not replaced after testing due to human error. Does that then mean that it must be inspected when it is replaced?
   

Satobsat
Oct 19 2019 10:07

Might see if I can find it on the HRDB. Then get the inspector back for free to do what he should have done in the first place. What year did it become mandatory for RCDs to feed no more than 3 circuits?
   

AlecK
Oct 19 2019 12:34

The 3-subcircuit rule came in with A1 to 3000:2007; so became mandatory in NZ from introduction of ESRs 1/4/10.

The HRDB doesn't go back that far - even if the original work (moving the MEC to inside swbd)was ever inspected in the first place. The HRDB came in with 2013 amendment, so only records from 31/12/13.

removing / replacing the MEN link for testing is specifically exempted from being "mains work", but that's not an accurate description of what happened here. There was clearly mains work of installing new electrode & MEC, which should have been inspected - but probably wasn't.

For what you've done, while technically only the relocating the MEN link - from original to new location - requires inspection; having that inspected means someone else will be at least running their eyes over the main safety elements of the entire set-up; which can't be a bad thing.