New CU

i agree big nev, finding it difficult to take it all in. What amazes me is that if it is that meaning FWL that you have RCBO then why is BR stating that it's a bit OTT. surely it may be a bit more expensive in the long run but safety is a must.

I didn't know the fact about the oven and Hob being the appliance being tiop to give the most electric shocks, how does that occur then, through the electric ignition etc. I would of thought an iron or even overloaded plugs.
 
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bignev said:
Sorry to interrupt the debate chaps but i'm now confused again. I understand the theory in splitting the kitchen, but RCD/RCBO on the downstairs or upstairs ring yes/no and WHY.

FWL is right, there is no reg which says that all sockets must have RCD protection, (although IMHO it is a good idea). It is required (but I know not the reg number) for all sockets which might reasonably be expected to supply equipment outside. So if you live on the 20th floor of a block of flats, none of them. House - ground floor and those which are actually outside (shed/garage etc).

But I find a very simple rule works.

Protect every circuit except those that you really shouldn't like lights, alarms, fridge/freezer, granny's iron lung etc.

And then argu^H^H^H^Hdebate with FWL the relative merits of RCDs/RCBOs, discrimination etc.
 
Depends whether you want to inherit from Granny sooner or later......... :evil:
 
FWL_Engineer said:
BR..PLEASE quote the regulation that states all sockets need to be protected by an RCD?? Oh you can't, there isn't one.
The regs state any socket, which could be used to supply a device to be used outside. Do you fit notices beside sockets in your house - This socket can be used to supply equipment to be used outdoors, but this socket here cannot! OK! I’m joking, but in all honesty FWL i cannot see where your coming from with this and in my opinion is poor design. BTW, in Ireland all 13A socket circuits in a domestic installation must be RCD protected

As for 30mA in the kitchen...hello, harmonics on the neutral from inductive loads will likely trip a 30mA RCBO, remember that RCBO's are DC sensing and they will trip if you have enough inductive appliances in your kitchen. such as electronically controlled washers, dryers, fridges and freezers.

this is a domestic installation, not a commercial one. The number of such appliances required to trip even a dc sensing RCBO would be way beyond the number of such appliances likely to be installed in a domestic kitchen.

You bang on about sockets being RCD protected then you make that comment about not protecting what is likely the largest drawing device in the house. the cooker.

Did you know that 80% of electric shocks in domestic premises arise from Cookers and hobs!!

No, i did not know that, and i don’t accept it, at all!
Would love to know where you got the figure though!
I did say that 'in my opinion' this circuit did not need to be RCD protected. Please note that this is also the opinion of RECI and ETCI in Ireland.
 
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Bignev, there is a school of thought that advocates putting RCD on everything from the toaster to the kitchen sink.

There is nothing wrong with RCD protection, if used wisely though.

RCD main switches are good in certain installations, but not in the home, the RCD pops, you have no lights, you break your neck falling down stairs to reset the RCD..you didn't die of electric shock though!!

RCD protection has been advocated for sockets on the ground floor of installations because people have a habit of using electric equipment out doors and then damaging the cable or the tool, and getting serious shock or worse as a result. The problem with this is that electronic equipment uses switched mode power supplies, of a type most commonly found in computer equipment. These types of PSU's create what are call harmonic currents, and they appear on the neutral conductor or the earth, in domestic situations they are 99% found on the earth cable.

The problem is that these harmonics are the very type of current that RCDs detect, consequently if they build up enough then the RCD operates. Each piece of equipment will typicaly create about 5mA of harmonic current when in use. In your home the type of equipemtn that does this are, Hi-Fi seperates/systems, TV's, satellite/cable TV boxes, video's, DVD's, computers and related equipment, plug in phone chargers etc.

Many years ago this was not a real issue, but in the last 5 years or so the growth in the the of the switched mode PSU in just about everything has sky-rocketed. This is creating real problems in some households.

I don't have enough hours available tonight to list all the call-outs we have attended in the last 6 months caused simply by harmonic currents causing RCD's to operate. This costs the home-owner money.

Many will try to say there is a regulation to cover this, there is not, and the NICEIC do not advocate putting all sockets on RCD protection.

Kitchens present a special danger, we all switch things on and off, plug things in and out with wet or at least damp hands, we shouldn't, but we do. This creates significant risk of shock, and as such the installation of an RCBO protected ring main is critical in the kitchen. If you budget can stretch to it, the obvious compromise would be two circuits in the kitchen, an RCBO circuit for sockets on the worktops, and a MCB type B protected circuit for the outlets feeding the fridge, freezer and similar white goods, although washing machines do present a significant risk, they are likely to trip dc sensing devices.

If you have a socket that is likely to be used to feed a lawnmower or used outside, then there are a couple of things you can do. Firstly you could install a circuit, MCB controlled, that feeds a waterproof socket mounted on the outside of the house, this will incorporate an RCD for protection locally. Secondly, you could install an internal RCD protected socket closest to your rear door, where your likely to run cables from into the garden, or thirdly, you can simply protect the circuit in the kitchen that this socket will be on with an RCBO.

The use of RCD/RCBO protection upstairs is not required, however I would add one word of caution. If you intend to put sockets in your loft void, I would use RCD protected sockets should you spur them from the upstairs ring, unless you are 100% confident that no moisture can enter the void.

The decision about what you do in your home is your decision, of course there is always the cost to consider, make no mistake, RCBO's come in at about £40 each, as opposed to £7 for a Type B MCB. You know what equipment you have in your home, we do not, and you know how it is used. You need to consider all these points carefully, then look at what you can afford to pay to achieve your aims of a new installation, but be assured that it will operate effectively and how you want it to.
 
andemz said:
i agree big nev, finding it difficult to take it all in. What amazes me is that if it is that meaning FWL that you have RCBO then why is BR stating that it's a bit OTT. surely it may be a bit more expensive in the long run but safety is a must.

I didn't know the fact about the oven and Hob being the appliance being tiop to give the most electric shocks, how does that occur then, through the electric ignition etc. I would of thought an iron or even overloaded plugs.

I didn't say it was OTT. I have 30ma RCBO's in my own house. The point i was making is that they are a much more expensive option than a split load setup. One advantage of them is that all circuits will not be left without power in the event of a fault on one although they have many other properties making them more suitable than split load for certain types of installation. Safety isn't really an issue.

As for the second point of FWL's you refer to..............absolute ***** sorry wait until we see where he got it from!
 
OK - PLAN Z

2 small boards, each with a few spare ways. Neither split load.

1 with RCD, 1 without.

Start out with the conventional RCD/non-RCD split of circuits.

If you get nuisance trips of the RCD from a circuit that you would like to be protected, buy an RCBO and move it to the non-RCD board.
 
am i right in saying then that RCBO's don't come standard on consumer units, you have to buy these and then put them into the consumer unit on a blank section of the consumer unit. Then if that's correct do you need to buy the right RCBO for the particular consumer unit you've got.
 
I agree with alot of you points here however to pick one:

Computer room in school with 32PC's with associated hardware monitor, speakers etc. (supplied via 3 X 20A rings)
2 televisions
2 printers
1 projector (cant think what you call them, computer can be connected to them along with t.v)
4 scanners

All protected with a single 30MA 63A RCBO (main switch)

This is something i came across recently, bad design i know but can you explain why the RCD 'very rarely' trips. And it's not faulty, i tested it myself

So that’s 5Ma for every PC and t.v and lets just say 15Ma for the rest.
= 185Ma If your theory (5Ma for every device) was correct this RCD would be overloaded X 6!
 
ban-all-sheds said:
OK - PLAN Z

2 small boards, each with a few spare ways. Neither split load.

1 with RCD, 1 without.

Start out with the conventional RCD/non-RCD split of circuits.

If you get nuisance trips of the RCD from a circuit that you would like to be protected, buy an RCBO and move it to the non-RCD board.

Why ban? what is the advantage of this over a split load board? There is nothing stopping you from fitting an RCBO to a split load. In Ireland reci rules state that the shower circuit must be protected by an RCBO. So this is simply installed in the 'non rcd side' if you like of a standard split load board.
 
BR said:
[The regs state any socket, which could be used to supply a device to be used outside. Do you fit notices beside sockets in your house - This socket can be used to supply equipment to be used outdoors, but this socket here cannot! OK! I’m joking, but in all honesty FWL i cannot see where your coming from with this and in my opinion is poor design. BTW, in Ireland all 13A socket circuits in a domestic installation must be RCD protected

BR, the Regulation that you are mis-reading is 471-16-01, and this a verbatim quote from the CD.

471-16-01 A socket-outlet rated at 32A or less which may be reasonably expected to supply portable equipment for use outdoors shall be provided with supplementary protection to reduce the risk associated with direct contact by means of a residual current device having the characteristics specified in Regulation 412-06-02(ii).

This Regulation does not apply to a socket-outlet supplied by a circuit incorporating one or more of the protective measures specified in items (i) to (iii) below and comply with the Regulations indicated:

(i) protection by SELV (see Regulations 411-02 and 471-02)
(ii) protection by electrical seperation (see Regulation 413-06 and 471-12)
(iii) protection by automatic disconnection and reduced low voltage systems (see Regulation 471-15)

Now it states REASONABLY, hence putting kitchen circuits on RCBO protection but not the lounge or hallway.

Now, in Guidance Note 1, Selection and Erection of Equipment it states..

It is recommended that the use of residual current devices or RCBO's are used to ensure that there is adequate overcurrent, direct and indirect contact protection to circuits supplying sockets-outlets in domestic kitchens, this is especially true should any of these socket-outlets be reasonably assumed to be used for the supply of portable equipment outdoors (Regulation 471-16-01)

It also states:

where socket-outlets can be deemed not to be used to supply portable equipment outdoors, or where this circuit may be used to supply electronic office equipment or similar then there is no requirement to afford this circuit the protection of a residual current device or RCBO.

It may be easy for people to just shout RCD from the rafters, but when designing an installtion it helps to understand all the potential factors that may be placed upon that installation during normal use. Protection by RCD/RCBO is important for circuits that poses a higer level of risk, but there is no need for them on every socket circuit.

BR said:
this is a domestic installation, not a commercial one. The number of such appliances required to trip even a dc sensing RCBO would be way beyond the number of such appliances likely to be installed in a domestic kitchen.

Get a life fella, I could easily pop a 30mA RCBO in my kitchen, there is nothing wrong with my appliances, but the combined output of them when all on at the same time are sufficient to drop out a 30mA RCBO, and my home is no atypical. The average washing machine, tumble dryer etc will create a total harmonic current in the region of 5mA, fridges and freezers can create surge harmonics in the region of 35mA on their own (although manufacturers are reducing this year on year)

No, i did not know that, and i don’t accept it, at all!
Would love to know where you got the figure though!
I did say that 'in my opinion' this circuit did not need to be RCD protected. Please note that this is also the opinion of RECI and ETCI in Ireland.

The figures come from HM Government..the exact figure to be precise is 78.3% (I simply rounded it up for typing ease).
The RECI and ETCI may control what Irish Sparks do, but they do not control what we do in the UK, both the IEE and the NICEIC recommend that cooker circuits be afforded RCBO protection due to the greater risk they pose by the combination of electricity, conductive liquids, bad maintenance and high load potentials.[/quote]
 
BR said:
I agree with alot of you points here however to pick one:

Computer room in school with 32PC's with associated hardware monitor, speakers etc. (supplied via 3 X 20A rings)
2 televisions
2 printers
1 projector (cant think what you call them, computer can be connected to them along with t.v)
4 scanners

All protected with a single 30MA 63A RCBO (main switch)

This is something i came across recently, bad design i know but can you explain why the RCD 'very rarely' trips. And it's not faulty, i tested it myself

So that’s 5Ma for every PC and t.v and lets just say 15Ma for the rest.
= 185Ma If your theory (5Ma for every device) was correct this RCD would be overloaded X 6!

Have you checked the RCBO?? What type it is, it's technical specs, probably not. What make are the MCB's?

Merlin-Gerin and many other makes of MCB stop many harmonic currents due to their design..not an intentional benefit as I understand things, just a lucky one, so if they are going through the MCB before reaching the RCD, as you imply, then that would seriously reduce the harmonics from the neutral side.

If the RCD is NOT DC sensing or DC pulse sensing, then anything on the Earth will not be detected as it is not electrically connected to it.

Remember, the DC sensing and DC Pulse sensing have tails that connect to the Earth block.

Not all RCD's are the Same, there are different types for different installations.

So BR, next time you wish to say I am talking ****, get off your fat arse and actually do some research before commenting. You are certainly a case of the Pot calling the kettle black.

I apologise to the others for this last little outburst, but I am getting tired of slackjawed wannabe's from slagging me off when they don't fully know what they are talking about.
 
andemz said:
am i right in saying then that RCBO's don't come standard on consumer units, you have to buy these and then put them into the consumer unit on a blank section of the consumer unit. Then if that's correct do you need to buy the right RCBO for the particular consumer unit you've got.
Same applies to incomers and MCBs - no guarantee of interchangeability.
 
BR said:
ban-all-sheds said:
OK - PLAN Z

2 small boards, each with a few spare ways. Neither split load.

1 with RCD, 1 without.

Start out with the conventional RCD/non-RCD split of circuits.

If you get nuisance trips of the RCD from a circuit that you would like to be protected, buy an RCBO and move it to the non-RCD board.

Why ban? what is the advantage of this over a split load board? There is nothing stopping you from fitting an RCBO to a split load. In Ireland reci rules state that the shower circuit must be protected by an RCBO. So this is simply installed in the 'non rcd side' if you like of a standard split load board.

You could use a split load board, but you might need a pretty big one to give you the flexibility to move a lot of circuits around.
 
so can you buy a consumer unit with RCBO's and MCB's already in. I've just had a quick look on tlc-direct but they are minus the MCB's. Know anywhere where they sell quality Consumer units, hager merlin green etc not wylex with MCB's and RCBO's already in.
 

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