4th Edition advice please

rum and coke

Hi
I'm a sparks but haven't done much domestic installation. I'm building my own house and so I'm wiring it myself.I just want to ask a couple of questions.

Are bathroom lights now to be rcd connected,have they to be on their own circuit.If yes will that cause nuisance tripping.

Do I need a rcd for sockets and a seperate 1 for immersion heater.I will have a water pump so will I need a third 1 for that.Do you experienced domestic guys have an rcbo for shower,one for immersion and a third one for the water pump.I have a central heating boiler is that a fourth rcbo.I may also have 2 pump showers.Thats heading for 6 rcbos. is that the way its done now.

Earthing I figure 10 sq to hot press.What about kitchen can I take a 2.5 from closest socket.Do all bathrooms need an earth(rads,sink bath) Does the bath need a 10 sq.Do I need to earth boiler or main gas incomer.

1 last one.I've heard the mains need a mcb in meter box?


Thanks in advance

Solair

I don't know what all the fuss about nuisance tripping is to be honest.

If you need to put bathroom lights on an RCD, can't they just be put on a a 6 or 10amp 30mA RCBO for each bathroom covering the lights+fan.

.G.

rum and coke wrote: »

Hi
I'm a sparks but haven't done much domestic installation. I'm building my own house and so I'm wiring it myself.I just want to ask a couple of questions.

Are bathroom lights now to be rcd connected,have they to be on their own circuit.If yes will that cause nuisance tripping.

Yes seperate RCD circuit for bathroom lights or RCBO

Do I need a rcd for sockets and a seperate 1 for immersion heater.I will have a water pump so will I need a third 1 for that.Do you experienced domestic guys have an rcbo for shower,one for immersion and a third one for the water pump.I have a central heating boiler is that a fourth rcbo.I may also have 2 pump showers.Thats heading for 6 rcbos. is that the way its done now.

You can use individual RCBO's for sockets immersion etc if you want but its not a requirement. one rcd covering those circuits individual mcb's is fine.Except the shower that should have its own RCBO

Earthing I figure 10 sq to hot press.What about kitchen can I take a 2.5 from closest socket.Do all bathrooms need an earth(rads,sink bath) Does the bath need a 10 sq.Do I need to earth boiler or main gas incomer.

Main bonding should be at least half the CSA of the largest protective conductor in the installation but not less than 10sq copper.Bond structural metal parts,incoming water,incoming gas,central heating systems etc.Supplementary bonding should be minimum 4sq in bathrooms etc unless it is mechanically protected in which case 2.5sq is the min.Kitchen sinks etc still connected to local earth in a socket or whatever.

1 last one.I've heard the mains need a mcb in meter box?

Yes I believe this is the case but the other lads here will confirm


Thanks in advance

No more rings in Kitchens need at least 2 radials and sockets that are inaccessible,eg behind the washing machine etc,have to have a Double pole isolator on them which is easily accessible.

I'm sure Meercat,M cebee,2011 and Robbie7730 etc will have more input

TheBody

superg wrote: »

No more rings in Kitchens need at least 2 radials and sockets that are inaccessible,eg behind the washing machine etc,have to have a Double pole isolator on them which is easily accessible.

I'm sure Meercat,M cebee,2011 and Robbie7730 etc will have more input

Agree with superg on all. Also, just to confirm you do need an mcb in the meter box.

evosteo

hi superg can you explain this part

Supplementary bonding should be minimum 4sq in bathrooms etc unless it is mechanically protected in which case 2.5sq is the min

pieface_ie

mechanically protected

Conduit

evosteo

pieface_ie wrote: »

Conduit

in a domestic premises?

honestly if never heard of that

iv always just seen 2.5sq looped in a bathroom from rads, to sink, to bath to make sure all the exposed metal parts will be at the same potential

rum and coke

Thanks for the replies guys.I appreciate it.To superg I'm attaching a download from hager regarding seperate RCD'S for water heating devices.Perhaps you could have a look at page 11 and 12 and let me know your take on that.

Kind regards

.G.

evosteo wrote: »

in a domestic premises?

honestly if never heard of that

iv always just seen 2.5sq looped in a bathroom from rads, to sink, to bath to make sure all the exposed metal parts will be at the same potential

Yeah 2.5 is all I've ever seen too but it is in the rules that it should be 4sq unless in conduit etc.Rule 544.2.2

pieface_ie

in a domestic premises?

honestly if never heard of that

iv always just seen 2.5sq looped in a bathroom from rads, to sink, to bath to make sure all the exposed metal parts will be at the same potential

Never came across it myself, its stated in the regulations though. Its just bonding in general not specifically for bathrooms.

.G.

rum and coke wrote: »

Thanks for the replies guys.I appreciate it.To superg I'm attaching a download from hager regarding seperate RCD'S for water heating devices.Perhaps you could have a look at page 11 and 12 and let me know your take on that.

Kind regards

It looks to me that the info in that is inaccurate.If you look at the actual rule they refer to it states

"A circuit supplying a water heating appliance........Shall be protected by an RCD having a rated residual operating current not exceeding 30mA.

A seperate RCD or RCBO shall be provided for each shower unit"

No mention in that about seperate RCBOS or RCD's for each water heating unit So as I mentioned,shower gets its own RCBO,and the immersion goes on the same RCD as the sockets.RCBO for the bathroom too.

If you want you can use RCBO's for each,up to you.

meercat

rum and coke
best of luck with your house build

agree with other posters here
other things to note
distribution board min height 1.4 mts to bottom/max 2.25 to top

mains operated smokes in hall, landing ,main living area(sitting room)
heat detector in kitchen(interlinked with all smokes)
these are the minimum,you may require more

separate circuit for freezer not on rcd connected with fused spur( or on its own rcbo if connected to socket)

rcd protection on all lighting points not attached to main building(garden lights,driveway lights,pier lights etc)

water pumps must be protected by rcd(this includes heating circulation pumps)

as this is your own house my advice is to install a 3 row board and install rcbo for every circuit(i know this is overkill but its your own house)
we are nearly at the stage when rcd protection will be compulsory for the whole installation
rcbo will help isolate and identify any future faults

i would also install an emergency light near the fuseboard and on the landing and near the front door(a recess downlight can be adapted)

keep updating your progress

jdesbt

is the mcb in the meter box not only a requirement if the fuseboard is more than a certain distance away.

M cebee

jdesbt wrote: »

is the mcb in the meter box not only a requirement if the fuseboard is more than a certain distance away.

Yes theres something in there on that
as the mcb is primarily providing SC
protection

jdesbt

i think its 5 meters

rum and coke

Thanks again for replies. I was told 3 metres.
To meerkat I would love to put all circuits on rcbo's but it would be overkill and money is tight.
Why have we moved from ring circuits.What was wrong with them.

pieface_ie

There's a safety aspect to ring circuits. If there is a break in the ring you will end up with two 2.5mm sq cables been protected by a 32A protective device.

M cebee

and even worse case scenario

its not unknown for the legs to be inserted in different breakers at a later stage in domestic work

evosteo

M cebee wrote: »

and even worse case scenario

its not unknown for the legs to be inserted in different breakers at a later stage in domestic work

have seen that happen alot lately on alot of recent builds?

jus wondering i heard a while ago that their may be a requirement to have an emergency fitting located in the bathroom on its own circuit protected by a rcbo,

any truth to this?

was this rule implemented or was it just a recomendation?

M cebee

evosteo wrote: »

M cebee wrote: »

and even worse case scenario

its not unknown for the legs to be inserted in different breakers at a later stage in domestic work

have seen that happen alot lately on alot of recent builds?

jus wondering i heard a while ago that their may be a requirement to have an emergency fitting located in the bathroom on its own circuit protected by a rcbo,

any truth to this?

was this rule implemented or was it just a recomendation?[/Quote

not for domestic-an amendment clarified it

for hotel b&b yes

Bruthal

pieface_ie wrote: »

There's a safety aspect to ring circuits. If there is a break in the ring you will end up with two 2.5mm sq cables been protected by a 32A protective device.

Or earth open circuit so a 1.5 earth for a 5 square 32 amp circuit, or both ends of loop into different breakers as m cebee said, a good possibility when a board is upgraded and no proper awareness of ring main possibility from the installer.

None of the above are self monitoring like a radial would be.

Never wired a ring main circuit in a domestic installation myself.

meercat

evosteo wrote: »

have seen that happen alot lately on alot of recent builds?

jus wondering i heard a while ago that their may be a requirement to have an emergency fitting located in the bathroom on its own circuit protected by a rcbo,

any truth to this?

was this rule implemented or was it just a recomendation?

they aborted the requirement for an emergency light but kept the rcd protection though

jdbest
"is the mcb in the meter box not only a requirement if the fuseboard is more than a certain distance away."

the main protective device for the installation must be situated
1. at the main supply point(the origin of the installation) or
2. within 3mts of the meter(i.e. in the distribution board)provided the conductors upstream are mechanically protected and/or located so as to avoid risk of short-circuit and damage,and are not placed near combustible material.branch connections are not permitted.
where the device is located at the main supply point it may be located in a special compartment inside the standard meter cabinet.in which case the device must be an mcb.(430.4)

it would be more prudent to always install one imho

Bruthal

meercat wrote: »

it would be more prudent to always install one imho

Yea, just put one in any domestic installation that has a meter cabinet is the way forward. No thinking about distances etc.

mikejjp

The house I'm trying to finish off was abandoned 2007/8 with just the first fix wiring done. With the change from 3rd to 4th edition would you expect to have to re-cable any circuits or beef up the earth bonding? Anything else affecting first fix?

2011

No ring socket circuits, RCD for bathroom lighting and restriction on the hight to the top of your distribution board.

meercat

mikejjp wrote: »

The house I'm trying to finish off was abandoned 2007/8 with just the first fix wiring done. With the change from 3rd to 4th edition would you expect to have to re-cable any circuits or beef up the earth bonding? Anything else affecting first fix?

The rules aren't retrospective but it would be good practice to upgrade where possible

M cebee

no ring ccts kitchen

if its only at 1st fix stage now then surely it will have to be finished to 4th ed rules

M cebee

you might be lucky with cable lengths at db?

a kitchen ring cct
should be no prob to split up

Overswitches for sockets
and bathroom lights could be a bit of hassle

antlyn

RECI have been talking about banning 1.5mm single earth from their jobs as well so check with them if they are certifying the job. They want to use 2.5 single instead and its only the earth they are referring to

M cebee

reci can't ban 1.5 singles
Cpc-same size as live conductors except for t+e
Last time i looked anyhow

meercat

M cebee wrote: »

if its only at 1st fix stage now then surely it will have to be finished to 4th ed rules

work started before 30 sept 2009 and in substantial advanced state can be completed and certified in accordance with 3rd edition

http://reci.ie/Portals/0/14062%20RECI%20News_1.pdf

M cebee

if you mean using 2.5 pvc singles and 1.5 pvc earth in conduit for a socket circuit?-that's not allowed
They have to be same size

antlyn

It was brought up on a course recently they were arguing that the 1.5 single earth isn't strong enough under tension and were recommending 2.5 to be used

M cebee

meercat wrote: »

work started before 30 sept 2009 and in substantial advanced state can be completed and certified in accordance with 3rd edition

http://reci.ie/Portals/0/14062%20RECI%20News_1.pdf

Ya-thought it would have to be further advanced
The changes mentioned already wouldnt be critical
I'd fit cabinet mcb and rcd any pumps regardless

meercat

M cebee wrote: »

I'd fit cabinet mcb and rcd any pumps regardless

agree

Bruthal

M cebee wrote: »

reci can't ban 1.5 singles
Cpc-same size as live conductors except for t+e
Last time i looked anyhow

Probably in terms of 1.5 being weak in terminals they are talking about, rather than fault capacity.

M cebee

ya
but i can't see the problem myself anyway

antlyn

M cebee wrote: »

ya
but i can't see the problem myself anyway

Me either, but don't shoot me (the messenger)!!

2011

M cebee wrote: »

if you mean using 2.5 pvc singles and 1.5 pvc earth in conduit for a socket circuit?-that's not allowed
They have to be same size

As stated in the 4th edition of ET:101 ???

M cebee

2011 wrote: »

As stated in the 4th edition of ET:101 ???

Yes its in the rules

M cebee

my bad
Its either same size off the table
-or you can calculate it
Always same size ime

stoneyxox

Can I have one double pole isolator (20a) feeding two double sockets under the counter which supplies 4 appliances??

Tuco88

I'd say it's not ideal setup, say if there is an issue with one appliance all will have to be off I until it's un plugged.

meercat

stoneyxox wrote: »

Can I have one double pole isolator (20a) feeding two double sockets under the counter which supplies 4 appliances??

This is not permitted
Each appliance must have a dedicated and labelled isolator.544.3.5