L5512RVF Relay Module - Switched Neutral

Discussion in 'C-Bus Wired Hardware' started by pravp, Mar 22, 2013.

  1. pravp

    pravp

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    When I had this module wired, the user manual for the module itself showed a lamp connected through on of the relay modules utilising a switched neutral. As a result I wired up my entire board where I was switching the neutrals instead of the lives and the lives were always fed out.

    However, in some of the newer installation manuals there does not seem to be any indication as to if the neutral is switched or the live is switched.

    Switching a neutral would oviously be better for the relay itself in regards to arching etc. so just wanted to know if there is anything wrong with doing it this way?

    The downside being that all of the cables running out to the circuits are "live" all the time as the neutral is switched?

    Some of my work-in-progress photos attached, the system is fully installed now will post some final photos later on. I wired up the board "industrial style" with double stacked terminals.

    [​IMG]
     
    Last edited by a moderator: Mar 26, 2013
    pravp, Mar 22, 2013
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  2. pravp

    Newman

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    It is generally more preferable to switch the active than switch the neutral. There can be a couple subtleties to watch out for when switching neutrals as, when off, one side of the fitting is always at active potential. With a bit of capacitive coupling to earth through a fixture there can be small leakage currents that can flow.

    That's right, and this is generally not preferred.

    There is absolutely no difference in switching the active or the neutral in terms of stress/arcing on the relay.
     
    Newman, Mar 25, 2013
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  3. pravp

    pravp

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    What would be the side effects of this in terms of long term use? the light would stay on even though its off?

    So far there have been no issues with any or the lights and I have a mix of downlights (both halogen and LED) and standard light fixtures.

    This would be a relatively easy change in my Cbus board as I have used a terminal strip, however the only thing would be the wiring colour scheme within the board! I will have to rewire the common feeding the relays to be a live and then the common bank on the dual stacked terminals would be neutral instead.

    Finding the time though would be the issue, do you reckon there would be any issues with running things this way in the interim and if so for how long. As you suggested earlier there would be no difference switching the active or the neutral.
     
    pravp, Mar 26, 2013
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  4. pravp

    DarylMc

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    I suggest someone delete these posts before some criminal liability comes the way of Clipsal or feel free to explain why it is OK to switch the neutral for lighting loads.
     
    DarylMc, Mar 26, 2013
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  5. pravp

    pravp

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    Since you think this is "criminally liable" and you are an expert in this field I dont think it will be an issue for you to point to the AS/NZ standard that states switching a neutal is against the law?

    I will post an image from the Clipsal manual which lead me to conclude that the neutrals need to be switched.
     
    pravp, Mar 26, 2013
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  6. pravp

    DarylMc

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    Please post the image from the Clipsal manual
     
    DarylMc, Mar 26, 2013
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  7. pravp

    DarylMc

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    It is only my opinion that it is dangerous to switch the neutral for lighting.
    I looked in AS3000 for a rule and could not find it.
    But I am happy to forward it to the relevant state electrical safety office to see what they think.
     
    DarylMc, Mar 26, 2013
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  8. pravp

    pravp

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    What do you make of this from the installation manual that came inside the box?

    I certainly read it like a switched neutral

    [​IMG]
     
    Last edited by a moderator: Mar 26, 2013
    pravp, Mar 26, 2013
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  9. pravp

    Ashley W

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    The current installation guide for that product is a little bit clearer in so far as it doesn't really matter from an operational perspective. If switching neutral in practice or not is a good idea is a different story. As others have said switching active or neutral doesn't matter to the relay, though me personally I would be switching the active because the last thing I want is voltage on a light that is 'turned off', or in your case having an exposed link bar that is live, when it is just as easy to have that as neutral.

    I do wonder how old the document you posted is or if they are instructions for another country. Never seen a document that says an MCB is required for every channel either.
     

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    Last edited by a moderator: Mar 27, 2013
    Ashley W, Mar 27, 2013
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  10. pravp

    DarylMc

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    I think there is a number of dangerous things about the wiring on these boards.
    • It looks as if he plans to use a neutral link as an active link
    • Switching the neutral and having a continuous live feed to the lights
    • Since switching the neutral for lighting is an unusual practice I question the qualifications of the person to wire the installation

    Clipsal also needs to address the fact that he was sent installation instructions suggesting to switch the neutral.
     
    DarylMc, Mar 27, 2013
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  11. pravp

    Ashley

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    AS/NZS 3000:2009 Section 2.3.2.1.1

    (b) Neutral conductor
    (i) No switch or circuit-breaker shall be inserted in the neutral
    conductor?
    (A) of consumers mains; or
    (B) where the neutral conductor is used as a combined
    protective earthing and neutral (PEN) conductor for
    protective earthing of any portion of an electrical installation.
    NOTE: This requirement applies to situations such as an earth
    sheath return (ESR) system or a submain neutral used for
    earthing of an electrical installation in an outbuilding in
    accordance with Clause 5.5.3.1(b).
    (ii) A switch or circuit-breaker may operate in the neutral conductor
    of circuits other than those in Item (i) where?
    (A) the neutral pole of a multi-pole switch or circuit-breaker,
    having an appropriate short-circuit breaking and making
    capacity, is linked and arranged to switch substantially
    together with all active poles; or
    (B) the switch or circuit-breaker is linked with corresponding
    switches so that the neutral contact cannot remain open
    when the active contacts are closed.
    A switched neutral pole shall not open before and shall not close
    after the active pole(s).


    So you can't switch a neutral unless you also switch the active at the same time. End of story.

    Personally I think any discussion on the mains side of C-Bus should be banned. If you have to ask you clearly shouldn't be doing it (or you need a refresher course :) )
     
    Ashley, Mar 27, 2013
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  12. pravp

    jboer

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    Someone has done a copy/paste mistake that wasn't picked up by the looks. It obviously has been picked up as it was changed and the AS rule certainly is not new. Recalls have been done for less.

    However I do agree with Ashley, even though those boards look really nice and a lot of work has been done well, there are a few dangerous flaws. This would not have happened if they had been done or even checked by a competent licensed electrician. (I add competent because I have seen some very non-competent licensed electricians too :) ) I doubt in a court of law following the single sheet instruction manual would be much of a defense if something were to happen.

    Just my 2C
     
    jboer, Mar 27, 2013
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  13. pravp

    bmerrick

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    Hi Pravp,

    This is one forum post that I really should be staying away from (I don't have time to sit on future inquests etc).

    I see you are a new member and we all normally like welcoming people like yourself to the community with open arms.

    But....... I need to tell you, I have not seen a forum post with SO MANY senior members trying to help you by telling you to use an electrician or at least read and comply with the Australian wiring standards. Legally, all 240V MUST, MUST I'll say it again for clarity, MUST be performed by a suitably licenced AND qualified electrical contractor.

    Now many will say that this is just ridiculous for things like putting on a new 3 pin plug or fitting a dimmer etc. To some extent at that level I may agree with them BUT IT IS THE LAW!!!!

    You are wiring a Switchcboard and you are doing it completely the wrong, most illegal and most dangerous way possible. Please take note of the number of members, senior members etc all very experienced people telling you to get it checked.

    This is the most solid groundswell of collective care for you and your family that you can get. Get it checked by someone who knows what they are doing. For all your nice looking looms and nice crimps and all that, you are possibly mitigating many of the safety mechanisms designed to save you and your family from electrocution and or fire.

    Newman's warning alone about Earth leakage should at the very least worry you about the effectiveness of any protected power RCD/RCBO systems you are looking to implement.

    Please don't ignore all these (not so) subtle warnings. Your board design and approach is truly dangerous. Please do pay an electrical contractor to at the very least assess and rewire your systems to meet the standard.

    According to Australian Law, your house would likely have NO INSURANCE until you do.

    Good Luck,

    Brad
     
    bmerrick, Mar 27, 2013
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  14. pravp

    Ashley W

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    I am still very curious about the drawing he has posted. Where did that come from because it is clearly wrong, for Australia at least.
     
    Ashley W, Mar 27, 2013
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  15. pravp

    bmerrick

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    Here are some scans of some of the previous installation manuals I had for the relay. One is from 2003, one is from 2005 and one is from the previous model 5504RVF from 2001.

    So if there is an incorrect document, it would suggest that it was between 2001 and 2003. I think the picture is more likely from a unofficial 'training' guide, perhaps from another country.
     

    Attached Files:

    bmerrick, Mar 27, 2013
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  16. pravp

    znelbok

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    I just recently installed a relay and it had the same diagram in it showing the neutral being switched. This was in the instructions that were in the box with it.

    The relay was a 2012 built version.

    Mick
     
    znelbok, Mar 27, 2013
    #16
  17. pravp

    pravp

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    Hi all, thanks for the abundance of replies and advice from all of the senior members. Just so we are clear here that nobody is breaking the law;

    1. The installation was done by a licensed electrician
    2. I am an Electrical Engineer and not clueless, i realised there was something wrong with the relay module manual and hence the reason I am checking here. The boards were designed with dual RCD/RCBO's protecting both supplies to the two C-BUS boards as well as RCD's on the load side of each of the relay and dimmer modules. The boards were designed with safety, nuisance tripping and ease of installation in mind. The electrican who installed everything went through the manuals and both him and myself were puzzled in regards to what Clipsal were suggesting with their wiring diagram. Totally admit that it was our oversight in regards to compliance with AS3000 as we naturally assumed Clipsal will not provide drawings that dont comply with the standards!
    3. Now that I know the Clipsal manual is wrong and does not comply with AS3000 in regards to wiring recommendations, I will have the wiring changed to have the live switched instead. This is a relatively easy change in the board due to its design with terminals.

    I also have tried searching for my version of the manual which does not seem to be available online. The manual came in the box and was printed in 2011. the manuals floating around the internet were printed in 2003/4 so natural assumption was that the 2011 was more current.

    Someone needs to notify Clipsal/Schneider about this as this is a terrible oversight on their part. Lesson learnt on my part, even large MNC's like Schneider/Clipsal have copy/paste issues and poorly checked documenation.
     
    Last edited by a moderator: Apr 2, 2013
    pravp, Apr 2, 2013
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  18. pravp

    paulw11

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    The diagram posted is the same in the manual for relays I purchased last year. It is on page 7 and definitely shows the neutral being switched. The date on the back of the manual is listed as February 2011.

    The text refers to IEC60669-2-1 in regard to the need for MCBs on each channel - this is applicable in the UK and other jurisdictions where that standard applies.

    I am surprised that the electrician didn't think to query the diagram with Clipsal, because it is so against everything they would have done in their career even without referring to AS3000.
     
    paulw11, Apr 28, 2013
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  19. pravp

    pravp

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    The wiring on the c-bus boards has been revised to suit a switched active. Thank you all for your contribution and input in this major oversight in both the manual and the installation itself.
     
    pravp, Apr 28, 2013
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  20. pravp

    Phil1987

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    There are still some brand new L5512RVF's kicking around with the manual that shows to switch the neutral.

    Whilst I was waiting for my project to unravel the other day I thought I would flick through the manual of one I received last week, it had drawn the neutral leg feeding through the relay.

    Does anyone know if Clipsal have revised this? I know a lot of electricians that dont know/have the ability to work out how to connect this stuff and its only a matter of time before there someone else wires it up switching neutrals.
     
    Phil1987, Jul 10, 2013
    #20
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