# Forum Home Renovation Heating & Cooling  Split system tripping RCD - been told shouldn't be on an RCD?

## abitfishy

Hey all, 
A few years ago we have 2 Daikin split systems installed, a small 2.5kw in the bedroom (opposite side of the house to the fuse box) and a 6kw right next to the fuse box.  
The 6kw looks like it was installed on a seperate circuit, the 2.5kw in the bedroom was installed by plugging into an external powerpoint the electrician installed which sourced power from the main circuit (protected by an RCD). 
Last week we turned the bedroom unit on, and after a few minutes it tripped the RCD. We tried again, same thing. I then turned outside powerpoint off, then all back on, it ran for an hour or so, but I wasn't confident there wasn't a problem. I rang an electrician (I wasn't a fan of the guy who installed it anyway so rang someone else) who advised that they shouldn't be installed on an RCD protected circuit due to possibility of false tripping, but to ring Daikin first for a service call in case there is a fault with the unit (still under warranty).  
They came and were surprised to see it on an RCD circuit and said the same thing, that it shouldn't be. They tested the unit, did see it trip, but felt there wasn't a problem with the unit. In particular they said if the unit had a fault, it would most likely trip when turned on, not at varying times and that I needed to get it re-wired not on the RCD. When asked why after a few years he said that as components wear with age, whatever causes the false tripping can start. This is all exactly what was said by another independant electrician (so thats Daikin and 2 electricians so far) whom I rang before I rang the original guy with the 'evidence' as I didn't feel I should pay to have it re-wired when from what I was told should have been done seperately in the first place.  
Based on this information I rang the initial electrician to get him to come and redo it, and his response was that it was fine to install the way he did, 'I do a lot of them that way with no problem' and that its fine to install it on an RCD circuit. He couldn't redo it anyway as he had moved out of Sydney to far northern NSW.  
My question is this to all you electricians. Is it 'standards' not to put it on an RCD circuit, or is it just one of those things you don't do to minimise possible problems, or is it the type of thing that the manufacturers suggest not to and its up to the electrician. I'm just wondering what comeback I have towards the electrician since I'm likely to be up for a couple of hundred bucks probably to get a lecky out to get it rewired. I'd like to be able to send him the bill.  :Eek:  
Would it be safe to say due to being on the opposite side of the house it was a 'lazy' install by the electrician? I wouldn't think it overly difficult at time of install to do it the other way, the house is hardiplank and there is fairly good access under the house between the unit and the fuse box - as a matter of fact I can clearly see all the way from the unit to the other unit next to the fuse box and I've installed some additional phone points under the house quite easily (yes, I'm ACA licenced) and I was a 116kg chubby guy then.  :Biggrin:  
Sorry about the long and drawn out story but I think I needed to give you all the information I have and a better idea of the location etc. 
Thanks.

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## nev25

AS3000 reg 2.6.3.2 
Clearly states any additional GPOs (Power points) added to a circuit must be protected by a RCD 
Somewhere else in the regs it states all new circuit must be protected by an RCD
(oven use to be the exception but no so in the new regs)  
This is of course with GPOs 
Hard wiring is a different story  
In my option the original sparkie has done the right thing
And should be complemented for doing so 
To remove the original RCD and replace it with an C/B would be HIGHLY illegal 
I'm wondering what tests the Air-con So called experts did 
Get a sparkie in to megger the Air-con the prove there is no leakage.to earth 
My tip would be either the AIrcon is Stuffed or there is moisture in the power-point (assuming its a weatherproof out door unit) 
Its not uncommon to find these weatherproof GPOs full of earwig's or spiderweb that carry just enough moisture to trip the RCD

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## abitfishy

I don't think they meant remove the RCD and replace it with a circuit breaker, even I know thats moronic, I think they mean it should have been hardwired into its own circuit (as the bigger unit was) in the first place.

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## nev25

> I don't think they meant remove the RCD and replace it with a circuit breaker, even I know thats moronic, I think they mean it should have been hardwired into its own circuit (as the bigger unit was) in the first place.

  
 Did the unit come with a 3 pin plug???

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## abitfishy

> Did the unit come with a 3 pin plug???

  I would have a clue, he took it out of the box and installed it.  Currently its got what looks like a standard grey coloured 3 core lead with a clear 3 pin plug, plugged into a waterproof point.

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## nicm

Working in design of industrial electrical equipment, there is no reason for a device to leak current to earth while operating normally. I'd be weary of anyone who says otherwise or suggests it's normal for the RCD to trip !
With most split systems, there are 2 power sources required, one for the compressor the other for the head unit. Your plug does that go to the head unit or compressor ?  
nic

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## abitfishy

Wouldn't have a clue where the cord goes, I'll have to have a closer look. 
I don't think they said its normal for it to trip, but its common to false trip with aircons, apparently theres a similar issue with fridges?  Now this has been from Daikin AND 2 independant electricians have all given me the same info - odd its different info here.

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## nev25

> , but its common to false trip with aircons, apparently theres a similar issue with fridges? .

  Was the case 10 years ago but things like RCD and fridge design etc have changed   

> Now this has been from Daikin AND 2 independant electricians have all given me the same info - odd its different info here.

   Sound like a standard cope out responce like F**KED If I know
Too hard   
Tell then to read the regs

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## nev25

> , there is no reason for a device to leak current to earth while operating normally. I'd be weary of anyone who says otherwise or suggests it's normal for the RCD to trip !

  Couldn't agree more   

> , most split systems, there are 2 power sources required, one for the compressor the other for the head unit.

  Yeah most (But not all) the head unit gets it supply from the compressor unit.
(some older models the head unit plugged into a gpo and the compressor was hard wired)
I have come across some where the compressor gets it supply from the head unit (Some LGs are like this) 
I installed a small Fujitsu last Monday that the compressor was power from the head unit 
And the head unit just had a 3 pin plug.
and yes I installed it on its own circuit yes with an RCD as per as/nz 3000

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## elkangorito

My comments in blue.    

> Hey all, 
> A few years ago we have 2 Daikin split systems installed, a small 2.5kw in the bedroom (opposite side of the house to the fuse box) and a 6kw right next to the fuse box.   Are these kilowatts "refrigeration power" or "electrical power"?  
> Last week we turned the bedroom unit on, and after a few minutes it tripped the RCD. We tried again, same thing. I then turned outside powerpoint off, then all back on, it ran for an hour or so, but I wasn't confident there wasn't a problem. I rang an electrician (I wasn't a fan of the guy who installed it anyway so rang someone else) who advised that they shouldn't be installed on an RCD protected circuit due to possibility of false tripping, but to ring Daikin first for a service call in case there is a fault with the unit (still under warranty).   As Nev said, they MUST be installed on an RCD protected circuit, as per AS/NZ 3000.

   RCD's are electronic devices and as such, can fail easily if subject to faulty supply conditions (i.e. electrical storms, harmonics etc). My inference is that the RCD may be faulty. 
Most electrical motors (refrigeration compressors etc) do lose insulation resistance over time. Usually this takes many years. All electrical motors have a "residual earth leakage current", which is initially very small but gets bigger over time (many years). 
When motors are cold, their insulation resistance is usually quite high unless they are severely damaged. As a motor heats up, the insulation resistance drops. When you said, "*and after a few minutes it tripped the RCD. We tried again, same thing. I then turned outside powerpoint off, then all back on, it ran for an hour or so*", makes me think that if the motor was truly faulty and if the RCD was doing it's job, the situation you describe would not happen.
Based on your info, the RCD is is inconsistent with it's response.
I suspect the RCD.   
Typical problems.
If your air con unit is too big, the compressor will "short cycle", which will mean that it is not being adequately cooled by the refrigerant. This will shorten the life of the compressor both mechanically and electrically. 
As Nev said, the insulation resistance of the supply circuit may be low. This certainly needs to be checked. 
The RCD may be faulty. This can also be checked with appropriate equipment but it may be cheaper to buy a new RCD (make sure it is not cheap crap).

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## Timmo

I'm surprised at Daikin's response.
Every Daikin installation manual I have come across states that an RCD should be used.

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## Mojaord

Electrical wiring and connections should be made
by qualified electricians and in accordance with
local electrical codes and regulation. The air
conditioner units must be grounded.
The air conditioner unit must be connected to an
adequate power outlet from a separate branch
circuit protected by a time delay circuit breaker, as
specified on unit's nameplate.
Voltage should not vary beyond 10% of the rated.  
That's what it says on the installation manual, on my one. No mention of a RCD.

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## journeyman Mick

> .................That's what it says on the installation manual, on my one. No mention of a RCD.

  The requirement for a RCD would be from the Australian standard/wiring regulations which is a legal requirement, rather than the manufacturer's reccomendations which are a requirement for warranty purposes. 
Mick

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## sdrob

> I'm wondering what tests the Air-con So called experts did 
> Get a sparkie in to megger the Air-con the prove there is no leakage.to earth 
> My tip would be either the AIrcon is Stuffed or there is moisture in the power-point (assuming its a weatherproof out door unit)

  my two cents worth 
i would not megger the air cond unit full stop
meggering the unit to australian standards would most likely fry the electronics within the unit... as plumbers would know electric heaters can give down to earth readings as moisture can enter the heating elements...  
 if i installed the unit i would have hard wired the unit(no plug top) and not run a rcd at all
 some units can develop false trips, i would get a sparky to check the rcd and make sure that isn't faulty and that nothing else is on the circuit and a air conditioning tech to check the unit...

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## nev25

> i would not megger the air cond unit full stop
> meggering the unit to australian standards would most likely fry the electronics within the unit... .

  
Not if its done right 
DO it all the time    

> if i installed the unit i would have hard wired the unit(no plug top) and not run a rcd at all
> ...

  If it come with a plugtop and you cut it off to hard wire it in
Would that Void Warranty????

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## Smurf

> If it come with a plugtop and you cut it off to hard wire it in
> Would that Void Warranty????

  Not sure but here in Tas it is a requirement of the electricity supplier that, for most residential installations, the unit is hard wired. Reason for that is the separate metering with GPO's totally prohibited on heating circuits. I'm assuming that warranties are still valid but not certain.

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