RCD's on 3 phase socket outlets

Hi all,

In Australia and New Zealand we are legally bound to fit RCD protection to any 3 phase socket outlet rated at 20A or under that is intended for "general use" with a 30mA RCD device.

Safe to say that the amount of nuisance tripping I encounter with welders and portable machinery etc is a pain. Anyway safety is safety so I oblige, but generally exploit the loop hole and install 32A outlets instead.

I am curious where else in the world has compoulsory RCD 3 phase requirements similar to those in Aus / NZ?

HJTRBO said:

Hi all,

In Australia and New Zealand we are legally bound to fit RCD protection to any 3 phase socket outlet rated at 20A or under that is intended for "general use" with a 30mA RCD device.

Safe to say that the amount of nuisance tripping I encounter with welders and portable machinery etc is a pain. Anyway safety is safety so I oblige, but generally exploit the loop hole and install 32A outlets instead.

I am curious where else in the world has compoulsory RCD 3 phase requirements similar to those in Aus / NZ?

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Yes! but in the UK they apply to single phase circuits to.

Domestic single phase circuits should be protected by a 30mA RCD and "Mobile equipment" not exceeding 32A for use outdoors.
However, Agricultural premeses,construction sites,fairgrounds, caravan parks or "Special locations" (Anything remotely wet) also warrant an RCD.
The reality is that we fit RCD's everywhere!!!

RCD's ?

Residual Current Device - in the US we call them GFCI's or Ground Fault Current Interrupter devices.

Put a sticker on the outlet, with the purpose they are used for like a welding machine, then you do not have to use the RCD just the connectors for general use. (as in different machines.)

shooter said:

Put a sticker on the outlet, with the purpose they are used for like a welding machine, then you do not have to use the RCD just the connectors for general use. (as in different machines.)

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This is also true in the UK - but then Europes regulations are supposed to be "Harmonised".
Regulations do allow skilled persons to use unprotected sockets!

Be careful with the 32A outlets as a solution, there was an OHS ammendment that came out in New South Wales in February 2011 that gave a 4 year window until ALL outlets must be RCD protected.

bernie_carlton said:

Residual Current Device - in the US we call them GFCI's or Ground Fault Current Interrupter devices.

Click to expand...

I'm getting a bit sticky on RCDs - my Consumer Unit has a mid-board RCD that gets tripped by the pub (Public House = eating and drinking establishment) 150 yards from my house.

They have halogen/gas discharge lights in their car park and beer garden, and my RCD regularly (not everytime) gets tripped when they turn them off.

This has only started happening since a new supply cable (or sections of) was installed in the road from the substation.

My earthing is TT (an earth rod), it's been tested as 0.14 ohms Ze, which I understand is very good, so it seems as though I'm being hit by the transients other users are creating.

It's an on-going situation, the Distribution Network Operator (DNO) are saying my 30mA RCD is faulty, as it trips at 15-20mA, yet the manufacturer says that is normal.

I'm saying that I've had no problems since they laid new cables. Perhaps the Neutral/Ground connections haven't been done to spec in the supply.

I'm using my ControlLogix training rig to record the power-down time and date.....

Also nuisance RCD tripping

This is a problem I've been encountering with nuisance trips as well.I have a generator with 32 amp RCD's on a socket outlet feeding a gas well site. When the noise filters for the VSD get older the leakage current increses tripping our RCD's. I tried to find some info on whether we could install 100mA rcd's(don't like this as it's above 30 mA which can be fatal) or change them to circuit breaker's, and if we then had to hard wire them.As usaul it s hard to find a yes or no answer so if anyone could point me in the right direction it would be greatly appreciated.

ggc said:

Be careful with the 32A outlets as a solution, there was an OHS ammendment that came out in New South Wales in February 2011 that gave a 4 year window until ALL outlets must be RCD protected.

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Any word if that will make it into as/nzs3000 in the near future?

Currently i have energy safe victoria agreeing that the 32a socket on a 20a mcb and 2.5mm cable solution is an acceptable workaround.

A bit off topic, but answering dabas point. The RCD tests to show normal operation are that it shouldn't trip at half current, any thing above half current up to the full 30mA is a pass. I find that ABB RCDs tend to trip around the 20-21mA whereas Merlin Gerin are nearer to 28mA. I haven't tested other makes. So the manufacturer is correct that the RCD is within spec.

This is a problem I've been encountering with nuisance trips as well.I have a generator with 32 amp RCD's on a socket outlet feeding a gas well site. When the noise filters for the VSD get older the leakage current increses tripping our RCD's. I tried to find some info on whether we could install 100mA rcd's(don't like this as it's above 30 mA which can be fatal) or change them to circuit breaker's, and if we then had to hard wire them.As usaul it s hard to find a yes or no answer so if anyone could point me in the right direction it would be greatly appreciated.

Click to expand...

I use Zener Electric VSDs on swimming pools all the time and they fit low loss filters for me - never had a trip. The RCDs I use are from HPM Legrand.
In Ozz they also apply to single phase.
Basically RCDs on just about everything.

Not sure if the changes in NSW will be reflected in AS3000, but with the ongoing push to harmonise the OHS rules across states, I wouldn't be surprised to see the other states follow NSW's lead.

It is all in the latest A/NZ3000 wiring rools. You should have a look at the many pages of stuff that have been added for swimming pools - a veritable minefield.
I have to work with the switch board standards too.
Then there are the local rools for the supply authority to add more confusion.

BryanG said:

A bit off topic, but answering dabas point. The RCD tests to show normal operation are that it shouldn't trip at half current, any thing above half current up to the full 30mA is a pass. I find that ABB RCDs tend to trip around the 20-21mA whereas Merlin Gerin are nearer to 28mA. I haven't tested other makes. So the manufacturer is correct that the RCD is within spec.

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Thanks for that BryanG - do you know where that is documented ?

The DNO tested my RCD with a box that has switch-selecteable leakage - in 5mA steps. It didn't trip at 15, but did at 20.

Although the DNO has said I should replace the RCD, they have now said they will re-imburse me if I still get the nuisance trips afterwards. But I don't see the need to replace it at all if it meets spec.

I'm wondering why I'm getting "hit" by this disturbance - could it be the new supply cables haven't been rodded enough, and I've got the best earth route ?