is RCD mandatory on GPO?

Discussion in 'Electronics & Electrics' started by bonox, May 3, 2011.

  1. bonox

    bonox Member

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    I had a rather large electrical group in sydney out to install a pair of 20A GPOs (flat pin) in a residential property.

    Since they are primarily intended to run some heavy motors, I requested a quote for a pair of D curve breakers and whatever RCD is required to protect the pair of circuits.

    Quote was sent with 2x20A circuit installation+MCB/RCD noted, which I signed and returned.

    Happy fella turned up to do the installation, and left behind a pair of 20D mcb's and no independant RCD.

    Upon razzing head office I was told that no-one makes a combined rcd/mcb in d curve and because i was running machinery I didn't need an rcd.

    Now, since this is a flat pin gpo, i also plug my hand tools into the circuits (which is why I wanted GPO's and not round pin specials or hard wired machines) and the decision to ignore the RCD on the quote was not made in consultation with me.

    My question at this point, ignoring the poor customer service, is the legallity of having a pair of GPO's with no RCD - is this allowed? My way out of the mess is to back off to a C type RCBO (the circuits are slightly over-rated anyway and the 5-10n is sufficient for the motor start anyway since they are mostly unloaded at start) or to buy a plugin RCD to use with the hand-tools. This still doesn't help me if the presence of the pair of open outlets isn't legal though.
     
  2. aXis

    aXis Member

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    Can you keep the D-Curve breaker and get a seperate RCD?

    I'd hold them to their quote and ask them to come up with a fair solution.
     
  3. OP
    OP
    bonox

    bonox Member

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    i'd like that solution, which is the same pattern as the rest of the house. Will a 20A RCD handle 300A for 10 seconds? Not that it would actually see that, but i guess you need to size it to the rest of the circuit...?


    Still don't know if the existing installation contravenes the regulations in nsw though.... thoughts?
     
  4. RussellK

    RussellK Member

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    I'm pretty sure it does - if it's a new power point circuit, it's gotta have an RCD. If it was fixed wiring to a machine, ie. no plug & socket, then it wouldn't require one.
     
  5. sbadman

    sbadman Member

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    20A isn't that heavy, add another zero and you're starting to talk :p

    Seriously though, it is irrelevant what you intend to use the GPOs for, they are legally required to have RCD protection. Clipsal's RCD range for example has two and four pole available in 40 and 63A, which indicates their continuous current rating before they melt. There is no rule that says the RCD/MCB must be combined into one unit, but there is certainly one that all GPO's need RCD protection!
     
  6. BlueRaven

    BlueRaven Member

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    Any particular reason why you can't have one round pin/captive outlet + d-curve breaker installed for your plant and a standard GPO + combined RCD/MCB installed for your hand tools?

    Not exactly what you wanted, I know, but it just seems heaps easier to me. Plus, even the knobs that quoted you should be able to sort that out, and at a lower price too.
     
    Last edited: May 3, 2011
  7. xc351

    xc351 Member

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    a normal gpo requires a RCD but being a 20A and well its not a gpo circuit i think it doesnt.

    GPO is general power outlet.

    same how im 99% sure 15A aircon points don't need a gpo.

    i can check my as3000 friday if need be
     
  8. HotHed

    HotHed Member

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    i used to do installs in factories. You can buy GPOs with RCDs built into them, this sounds like your best option. (machines for one gpo, hand tools for seperate gpo with rcd)
     
  9. sbadman

    sbadman Member

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    No need :)

    Clause 2.6.3.2 Other electrical installations
    Additional protection by RCDs with a maximum rated residual current of 30mA shall be provided for final subcircuits sypplying -
    (a) socket-outlets having a rated current no exceeding 20A

    and 2.6.3.1 doesn't specify a maximum outlet rating at all, so even 15A aircon points need one. Basically, if it's possible for an unqualified person to plug and unplug from it, it needs one. Bear in mind that it's not limited to single phase outlets, 20A 3 phase outlets would be covered under this clause as well.

    I'd be betting that the person you spoke to at head office has never even read AS/NZS3000.....
     
    Last edited: May 3, 2011
  10. ArmoureD

    ArmoureD Member

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    As far as I know (since I last checked over a year ago) ALL socket outlets and lighting points are required to be on an RCD protected circuit.

    If the new sockets are on new circuits, they MUST be on an RCD.

    If the new sockets are attached to an existing non rcd protected circuit, then the circuit MUST have RCD protection installed.

    If the sparky swapped a worn/broken socket with a new identical one then they dont have to be on an RCD if an RCD was not originally installed. Although it is highly recommended.
     
  11. BAAZMAN

    BAAZMAN Member

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    If it is a fixed piece of machinery and therefore, assuming that it will remain the only piece of equipment used of the 20A outlet, it does not legally require a RCD.

    edit: but the outlet needs a label stating that it doesnt have RCD protection and that it is for a dedicated piece of equipment.

    That bieng said, you asked for and paid for an RCD and one should have been installed. As previously stated RCD modules can be installed at the GPO, especially easy if a "56 series" weatherproof/captive/industrial outlet has been used.

    edit2:
    just re-read OP and as you plan to use portable equipment on said gpo's, it does require a RCD
     
    Last edited: May 3, 2011
  12. OP
    OP
    bonox

    bonox Member

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    two machines = two circuits. These two points are intended to cover a pair of 4kW motors, a VFD and a welder. There's a very specific reason I wanted flat pin GPO's. I will only have a pair of machines running together, but they'll get swapped around regularly.

    That said, I see no reason why you shouldn't have an rcd on any equipment with a visible and unarmoured flex lead - it may be a 5hp saw, but that doesn't mean you can't damage the lead or get an internal fault that an rcd would pick up without you having to rely on a heavy earth lead to cover until the breaker blows.

    Especially when the breaker will let you put 300A through the circuit for a reasonable amount of time, it becomes a little about fire risk mitigation as well as personal safety.

    Old mate in charge of the job said he'd try to find a solution a couple of weeks ago - time to remind him I think....

    Thanks all for the AS feedback. Makes it even easier to argue for what I requested if the install is illegal.
     
    Last edited: May 3, 2011
  13. Nick_Henchel

    Nick_Henchel Member

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    Spot on. I was waiting for someone to bring this up. As stated a socket outlet (whether it be single or 3 phase) with a rated current of more than 20A doesnt need to be on a RCD by the regs.

    Saying that, if it were a residential premises where this socket outlet was being used to supply power to different appliances, i would probably still whack it on an rcd.

    Out of interest what the FLC of the motors you plan on running??

    Cheers, Nick.
     
  14. TERRA Operative

    TERRA Operative Member

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    When the AS3000 refers to fixed machinery (Clause 1.4.6 to 1.4.10), I think you'll find it makes no difference to the requirement of an RCD if it is connected to the supply via a socket outlet. (refer clause 4.3.1 to 4.3.4,

    If the machinery is bolted down, but you can still unplug it, the circuit requires an RCD as indicated by clause 2.6.3.1 and 2.6.3.2 as posted previously.

    There is no provision for a fixed appliance (1.4.7) not requiring an RCD if it is on a socket outlet.

    In fact, clause 2.6.3.1 (c) states that an RCD is required for "directly connected hand-held electrical equipment, e.g. directly connected hair dryers or tools;" when installed in residential, domestic or common areas.

    Clause 2.6.3.2 (c) reiterates the RCD being required for direct connected tools.




    Can people please stop inventing hearsay about these things? It's ignorant, stupid and just plain dangerous.
     
  15. 2xCPU

    2xCPU Member

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    Especially after the correct info has been posted.

    2.
     
  16. OP
    OP
    bonox

    bonox Member

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    19.6A

    4kW, pf 0.85 I believe

    edit: starting current on the datasheet is 115A
     
    Last edited: May 4, 2011
  17. RobRoySyd

    RobRoySyd Member

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    I'd simply have an inline RCD installed in the area where these GPOs are fitted. I've got one in my workshop that protects the 20A mixed circuit that it runs off. From memory the unit was made by Clipsal specifically for spas so it's weatherproof as well.
    The startup current of the devices should not be an issue that'll cause the RCD to melt, the current transformer inside the RCD is only measuring current difference and its output is under 1V, the device itself isn't handling the current directly as such.
    The electrical contractor may have done you a favour indirectly. Fitting a MCB/RCD combo in the switchboard is a bit cheaper than fitting a RCD in the area being protected but very inconvenient for the user / client. I'd just ask them to come back and do what I've suggested, heck even offer them a few extra dollars to get it done right.

    As for AS3000 I'd suggest it all gets a tad "grey" when you're running heavy machinery in a domestic situation. Is the workshop domestic? Should unqualified people be in that area at all? Given the type of equipment going to be used there, there seems to be considerable risks involved if unqualified people went in there and started to play around with the "toys". I'd suggest a lock on any access to the area would provide more safety for the "unqualified" than a RCD :rolleyes: . Not to say that you shouldn't have a RCD even if the regs let you get by without one, I'm saying that you should think about safety in a more holistic way.
     
  18. OP
    OP
    bonox

    bonox Member

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    ok, thanks. My secondary issue is that the work done doesn't meet the quote and also appears to be illegal.

    this isn't heavy machinery - we're talking a bandsaw and a mobile dust extraction cyclone that just happen to draw a little more current than some others. For general safety, it is my responsibility (just the same as an industrial workshop manager) to ensure that joe average doesn't wander in and fire them up. I lock the doors when i'm not around so the kids don't wander in. But most of all, I want the RCD I asked for for one major reason - the guy using all this equipment is me!

    This isn't a commercial outfit - it's my hobby. And you guys spend tens of thousands of dollars on your cars/home theatres etc - I spend mine on suitable machinery.

    Having said that though, qualified people still make mistakes and if the law says the outlet needs an RCD behind it then it doesn't matter if you are cutting your fingers off with a 300W saw or a 4,000W saw - an RCD won't stop you doing that anymore than a pool fence can stop you drowning in a glass of water.

    As also noted in the OP, these two outlets will have everything from this machinery to portable drop saws, soldering irons, lead lights, grinders, drill press, thicknesser and routers plugged into them - each with a plain old 10 or 15A flat pin plug on it.

    Is your in-line rcd in the fixed circuit (like a rcd socket) or in the flex lead for what you are plugging into it? I didn't know you could have a 20A mixed circuit. Or do you mean a 20A breaker on a circuit with 10A outlets?
     
    Last edited: May 4, 2011
  19. OP
    OP
    bonox

    bonox Member

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    Good news - they now agree that the installation needs an rcd and are arranging someone to rectify it.

    Thanks all. It's amazing how fast things happen when you mention a failure that leaves their arses hanging in the breeze.
     
  20. RobRoySyd

    RobRoySyd Member

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    I've run a standard 20A feed to the "shed" in 2.5mm cable protected by a 20Amp MCB in the switchboard. That feed just after it enters the shed runs through the RCD which is in a standard sized wall plate. You could mount that in anything really that met the usual requirements, I'm rather partial to Clipsal 238 mounting blocks these days.
    From there it feeds the lights and GPOs so everything in the "shed" has earth leakage protection.

    I just walked up to the "shed" for you. My bad the unit is made by PDL not Clipsal. Here's a link to it so it's still in production: http://www.productspec.net/products...ate-rcd-500-series-rcd-protected-devices.aspx

    Edit: I should say actually the feed is protected by a 16Amp MCB. I've never been overly happy rating 2.5mm at 20 Amps despite what the specs say. Your mileage may vary but I prefer to know that all my wiring is not glowing :)
     
    Last edited: May 4, 2011

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