# 30 mA RCD?



## TheRick (Apr 13, 2008)

I will be starting to inspect living quarters day after tomorrow, and have been doing some research...(FYI I am using the British Standards 16th Edition). According to 413-02-07 with a TN system overcurrent protection *OR *RCD protection shall be provided...correct?

If an RCD is used to fufil this requirement does it need to comply with 412-06-02 (30mA and 40mS) which it states is required to reduce shock risk?

These living quarters have no water or gas, and are simple ~10' X 20' one room structures for soldiers to sleep in.

THANKS :thumbsup:


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## Trimix-leccy (Dec 4, 2007)

Mmmmmm, it begins:laughing:

Another one to look at when I dig out the 16th edtn.

*I* would have thought RCD 30mA [backing up an MCB, or use an RCBO unit] as these will come under the mantle of 'temporary accomodation' or even 'mobile homes' [you call them trailers and we call them caravans:whistling2:] and from what you have said previously it sounds like a 'belt and braces' outlook is the way forwards. If you get 'nuisance tripping' it is better to wake up in the dark than to not wake up at all!!!


oh, and a Happy New Year!


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## AussieApprentice (Aug 16, 2008)

TheRick said:


> I will be starting to inspect living quarters day after tomorrow, and have been doing some research...(FYI I am using the British Standards 16th Edition). According to 413-02-07 with a TN system overcurrent protection *OR *RCD protection shall be provided...correct?


I don't know anything about the British Standards but I would not expect that you could have *either* over current protection *or* RCD protection. Everything should have over current protection and RCD may be an additional requirement.


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## TheRick (Apr 13, 2008)

AussieApprentice said:


> I don't know anything about the British Standards but I would not expect that you could have *either* over current protection *or* RCD protection. Everything should have over current protection and RCD may be an additional requirement.


:no:


To quote the BSI 16th Edition;

TN Systems

_413-02-07 *One* *or* more of the following types of protective device shall be used _

_ (i) an overcurrent device _
_ (ii) a residual current device_
_:yes:_

My question is does the requirement of 412-06-02 apply to this RCD protection...I am of the position that it does apply since it is being used as protection from electric shock, and plan to enforce to that standard.

Does anyone agree or disagree?

THANKS :thumbsup:


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## AussieApprentice (Aug 16, 2008)

TheRick said:


> :no:
> 
> 
> To quote the BSI 16th Edition;
> ...


I suspect that you are looking only at the sections relating to electric shock hazard. I am sure there would be a requirement for overcurrent protection somewhere as there is a fire hazard from an active-neutral short without it.


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## frank (Feb 6, 2007)

Hi Rick.

First things first. Your quote is from the 16th edition of the Regulations now superseded by the 17th Edition. The standard in this instance is just the same however but the Reg number is now 411-4-4.

This regulation concerns itself with automatic disconnection of a supply under fault conditions. A fault condition is regarded as an earth (ground fault via live and earth)You can therefore use an RCD or circuit breaker or fuse to comply. The regulation does not say this is sufficient for ALL conditions since you now have to consider ( overcurrent ) faults. Note here also that if you choose to use only an mcb/fuse for earth fault protection you must be able to meet the requirement of 411.4.5. - or use an RCD. Section 433 etc is the guide for overload protection and in most cases your expertise in selecting a suitable circuit breaker will normally suffice.

So to summarise - if you don't want to get overcomplicated with Impedance calculations etc then 1. Fit an RCD to protect ALL bus breakers.
2. Fit an MCB for each circuit.

Or if you want to provide individual circuit RCD and MCB protection then fit an RCBO.

Hope this helps.


Frank


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## TheRick (Apr 13, 2008)

frank said:


> Hi Rick.
> 
> First things first. Your quote is from the 16th edition of the Regulations now superseded by the 17th Edition. The standard in this instance is just the same however but the Reg number is now 411-4-4.
> 
> ...


 
The 16th Edition is all I have been given to go by, and enforce here.

My question was concerning panels mounted in the living quarters for soldiers, the feeders to these panels are protected with overcurrent devices (breakers), and the individual branch circuits have overcurrent protection. The mains in the panels are RCDs w/o overcurrent protection, some are 30mA and some are 300mA. What I am not 100% clear on is whether or not the 30mA protection is required, or if the 300mA will be compliant.

Thanks :thumbsup:


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## Trimix-leccy (Dec 4, 2007)

TheRick said:


> The 16th Edition is all I have been given to go by, and enforce here.
> 
> My question was concerning panels mounted in the living quarters for soldiers, the feeders to these panels are protected with overcurrent devices (breakers), and the individual branch circuits have overcurrent protection. The mains in the panels are RCDs w/o overcurrent protection, some are 30mA and some are 300mA. What I am not 100% clear on is whether or not the 30mA protection is required, or if the 300mA will be compliant.
> 
> Thanks :thumbsup:


 Why can't you have easy questions

300mA protects property
30mA protects people......a very generalistic overview all the same

Since the prime concern is people I would go for 30mA. Are these units metal bodied like ships containers or timberbuilt??


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## chrisb271 (Jul 6, 2007)

I've been reading through your NEC code on line and its a lot easier to get on with than the sh!t we use !!!
Problem with the British Standards is that they are open to interpretation and are ONLY a guide,we don't have any mandatory sections in there !

Don't mix 17th edition with 16th edition
It would help if all the replies stick with 16th edition.

*Reg *413-02-07 *One* *or* more of the following types of protective device shall be used 

_(i) an overcurrent device _
_(ii) a residual current device_

Both apply to socket outlets (receptacles) you need an overcurrent device (Mcb ) and Rcd (GFCI)this being no greater than 30mA for
Circuits feeding socket outlets ( this originally was brought in for power outlets outside the protected zone,outlets that fed equipment outside ) and was soon adopted for all power outlets.

*These Rcds should trip with 40 milliseconds at a current 5x 30mA =150mA*
*Or 200 milliseconds at 1x 30mA*
*If they DO NOT trip within these times then they should be replaced ASAP*

You can only test 100 and 300 mA rcds at 1x trip current.

Below is a 16th edition split load consumer unit ( Crabtree Brand )

View attachment 886



The service cable comes from the cut out ( service fuse ) into the top of the RED SWITCH on the right hand side,out the bottom of the same switch in a bus-bar connection and a wander lead from the neutral and the hot to the top of the Rcd 30mA the device in the middle of the distribution board.
The Service fuse provides overcurrent protection for the cable feeding the red switch (Main switch) and the Rcd (GFCI)
The Red Main Switch sometimes is not fitted and an RCD is used in its place,Usually 30mA or 100mA ( Not so often a 300mA ) If a 100mA one is used then a 30mA rcd is fitted to control the socket outlets ( receptacles)

See also below


View attachment 887


A likely combination would be in a distribution board would be

Red MAIN SWITCH or 100mA Rcd
Lights
Lounge heater circuit
water heater circuit
Smoke alarm
Cooker without socket outlet

30mA RCD (GFCI)
General socket outlets
power to outbuildings etc
outdoor lighting
cooker with a socket outlet


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