difference in electrics between UK & Ireland

Andy From Sligo

I noticed the other day that the RCD/ELCB in our consumer unit cover only the Sockets in the house - the ELCB is rated 80amps, the House was built in 2002. Now in the UK the RCD/ELCB would cover all earth leakage in the whole electrics of the house, the lighting circuit and the sockets - I just find it weird that the ELCB in our house in sligo just covers the sockets only because earth could leak to either pole in the lighting circuit just as well as in sockets. Each lighting point/switch/cieling rose has an earth wire to them, so this could mean in fact that if I broke a light switch and touched the live wire i could get a shock and without no ELCB on the lighting circuit , just a normal breaker (mcb) (5a or 10a) the electric would not cut off! - we rent this House and have has a electro mechanical and earth leakage tests as part of the landlords requirements for renting so it must have been OK not to have the lighting circuit not on the ELCB - but I just wonder why in the UK you have the ELCB protecting all the circuits in the house but the requirements in Ireland (if this is the norm ) dont wire the lighting circuit into the ELCB. And what do you reckon is best? - I would say its better to have the lighting circuit and everything wired through the ELCB.

Also why in the UK do they have 5a pull cord switches in the bathroom/toilets for the light but over here in Ireland they have normal switches but outside of the room, you could still touch them with ringing wet hands, however with a cord switch in the bathroom its much safer as well as more convenient is it not?

brightspark

I'm not sure where you got the idea that all circuits in the UK are protected by ELCBs (now referred to as RCDs). It's only since the latest 17th edition that the UK even required them on socket circuits. It is possible the the ELCB you saw in the UK protecting the whole house was a 100mA version, which is more for fire protection than to prevent electric shock. (The 30mA versions used on socket circuits now are designed to trip before fibrillation occurs at a typical value of just over 50mA)

To clarify the 16th edition only required them on sockets likely to supply equipment outdoors.

The reason for not putting everything on RCDs is that nuisance tripping would then cause a worse hazard (with the lights going out!).

Recent regulations here have added RCD protection to bathroom lighting circuits, using a separate RCBO.

Typically the risk from lighting circuits is much lower than socket circuits, you rarely touch the light fittings and the cables don't move. Whereas items plugged into sockets have exposed flexes and you often handle the appliance directly.

It is possible now that RCBOs are more common that eventually we will see new rules for all lighting circuits to be protected in some future version of the regulations.

As to the pull cord switch, it's the humidity inside the bathroom that causes the main risk, not just your wet hands. But I suppose you could extend the argument and replace all switches with pull cords, after all we often come in soaking wet from rain and turn on lights!

However I don't think I have ever got a shock from touching a light switch with wet hands.

Andy From Sligo

brightspark wrote: »

I'm not sure where you got the idea that all circuits in the UK are protected by ELCBs (now referred to as RCDs). It's only since the latest 17th edition that the UK even required them on socket circuits. It is possible the the ELCB you saw in the UK protecting the whole house was a 100mA version, which is more for fire protection than to prevent electric shock. (The 30mA versions used on socket circuits now are designed to trip before fibrillation occurs at a typical value of just over 50mA)

To clarify the 16th edition only required them on sockets likely to supply equipment outdoors.

The reason for not putting everything on RCDs is that nuisance tripping would then cause a worse hazard (with the lights going out!).

Recent regulations here have added RCD protection to bathroom lighting circuits, using a separate RCBO.

Typically the risk from lighting circuits is much lower than socket circuits, you rarely touch the light fittings and the cables don't move. Whereas items plugged into sockets have exposed flexes and you often handle the appliance directly.

It is possible now that RCBOs are more common that eventually we will see new rules for all lighting circuits to be protected in some future version of the regulations.

As to the pull cord switch, it's the humidity inside the bathroom that causes the main risk, not just your wet hands. But I suppose you could extend the argument and replace all switches with pull cords, after all we often come in soaking wet from rain and turn on lights!

However I don't think I have ever got a shock from touching a light switch with wet hands.

interesting and valid points you all made there brightspark - i never thought about all that obviously, just needed your expertise to make me sit back and think about it. Well done and thanks for taking the time to reply.

brightspark

brightspark wrote: »

However I don't think I have ever got a shock from touching a light switch with wet hands.

+1
...or fishing 16A connectors outtov pools.

The pull cord/switch is just an isolator though isn't it? Like on cookers? Never seen the need for two off switches on a device myself apart from servicing. Correct me if I'm missing something.

Andy From Sligo

Sir Liamalot wrote: »

... The pull cord/switch is just an isolator though isn't it? Like on cookers? Never seen the need for two off switches on a device myself apart from servicing. Correct me if I'm missing something.

The 5A pull cord switch i was referring to was for the light in the bathroom, but the likes of 45amp double pole pull cord switches i have seen over here do the electric showers.

maxfresh

I think the reasoning for not having lights on a rcd is not to have people left in the dark due to lights nuisance tripping
The pull cord switch is an option either switch on wall outside or pull cord inside

frankmul

Andy From Sligo wrote: »

I noticed the other day that the RCD/ELCB in our consumer unit cover only the Sockets in the house - the ELCB is rated 80amps, the House was built in 2002. Now in the UK the RCD/ELCB would cover all earth leakage in the whole electrics of the house, the lighting circuit and the sockets - I just find it weird that the ELCB in our house in sligo just covers the sockets only because earth could leak to either pole in the lighting circuit just as well as in sockets. Each lighting point/switch/cieling rose has an earth wire to them, so this could mean in fact that if I broke a light switch and touched the live wire i could get a shock and without no ELCB on the lighting circuit , just a normal breaker (mcb) (5a or 10a) the electric would not cut off! - we rent this House and have has a electro mechanical and earth leakage tests as part of the landlords requirements for renting so it must have been OK not to have the lighting circuit not on the ELCB - but I just wonder why in the UK you have the ELCB protecting all the circuits in the house but the requirements in Ireland (if this is the norm ) dont wire the lighting circuit into the ELCB. And what do you reckon is best? - I would say its better to have the lighting circuit and everything wired through the ELCB.

Also why in the UK do they have 5a pull cord switches in the bathroom/toilets for the light but over here in Ireland they have normal switches but outside of the room, you could still touch them with ringing wet hands, however with a cord switch in the bathroom its much safer as well as more convenient is it not?

Did the house in England have a TT supply? RCD protection is required on all circuit due to the nature of the supply. Most supplies in Ireland are TNCS.

Andy From Sligo

frankmul wrote: »

Did the house in England have a TT supply? RCD protection is required on all circuit due to the nature of the supply. Most supplies in Ireland are TNCS.

wow thats thrown me right out now with the TT and TNCS had to google it and come across wikipedia about the 2 systems - from that I gather that one system means the earth and neutral is connected and the other one has an earth rod in the ground by the house/pole am I correct in that? - in our house it looks like there is no earth rod around the grounds of the house so would that be a TT or TNCS system then?

Andy From Sligo

maxfresh wrote: »

I think the reasoning for not having lights on a rcd is not to have people left in the dark due to lights nuisance tripping...

Ah right I do see the logic in that, but would having lights on the RCD circuit cause that much tripping? - I mean I do know sometimes when a light bulb has blown in a fitting sometimes it trips the MCB in the consumer board, but not all the time.

Some of the lights on the lighting circuit(s) are outside lights - they would be subject to moisture and if the fitting breaks, water could leak onto terminals. It is that fact alone I would have thought sensible to have them on a RCD so the very instant of milliamps leaking to earth would trip the RCD, but would it be enough to trip the MCB? (which is rated at 10a or 15a I think on our lighting circuit in the consumer box).

tomdempsey200

afaik the UK now requires 30ma protection on all flush domestic circuits

so the new boards are dual rcd or all rcbo with 30ma protection on all circuits

Andy From Sligo

what does the O stand for in RCBO - I know the first bit would be Residual Circuit Breaker

Over-current

tomdempsey200

17th edition board

http://www.tlc-direct.co.uk/Products/WYNHISS15SL.html

DP main isolating switch
Dual rcd......all circuits rcd protected


http://www.eaton.com/EatonCom/ProductsServices/MEM/Products/ConsumerUnits/17thEditionRequirements/index.htm
rcd protection for buried and concealed cables, bathroom circuits and all sockets

Bruthal

brightspark wrote: »

It is possible the the ELCB you saw in the UK protecting the whole house was a 100mA version, which is more for fire protection than to prevent electric shock.

They can help with electrical fire prevention alright, but likely more used in houses to provide earth fault disconnection in TT systems, which would be unreliable when depending soley on an earth rod or rods, tripping an MCB, compared to an earth fault in a TN setup.

This in itself reduces the chance of a fire, but the main function is to reduce the required fault current required to operate a disconnection.

Andy From Sligo

so is a TT system the one with the earth rod or the one where the earth taps onto the Neutral on the pole/at the box? or is that a TN system?

Bruthal

TT is the earthing in the house directly connected to the earth via the earth rod. Because the transformer supplying the houses will have its neutral point earthed at the transformer location, this means there is a path through the earth rod, back the neutral. TT is for Terra Terra, (earth to earth). This path is often not of reliable low enough impedance to ensure quick operation of MCB`s, hence a main RCD.

TN has the earth bar connected to the neutral at the metering point. Our system is actualy TN-C-S. (Terra - Neutral - Combined - Separate) because before the neutralising connection outside the house, the earth and neutral path is in the one neutral conductor, but then separates after the neutralising point, coming into the house.

Neutralising ensures a low impedance path for earth faults, but it also means all metalwork connected to the earth bar can become "live" when there is an open neutral outside the house, the voltage level depending on the load on in the house, whether the neutral fault point is just for that house or a group of houses, and how good a connection the earth rod is making to earth, typically not great in most cases.

That`s where the importance of bonding comes in, so at least everything is at equal potential, which reduces shock risk.

Andy From Sligo

Bruthal wrote: »

TT is the earthing in the house directly connected to the earth via the earth rod. Because the transformer supplying the houses will have its neutral point earthed at the transformer location, this means there is a path through the earth rod, back the neutral. TT is for Terra Terra, (earth to earth). This path is often not of reliable low enough impedance to ensure quick operation of MCB`s, hence a main RCD.

TN has the earth bar connected to the neutral at the metering point. Our system is actualy TN-C-S. (Terra - Neutral - Combined - Separate) because before the neutralising connection outside the house, the earth and neutral path is in the one neutral conductor, but then separates after the neutralising point, coming into the house.

Neutralising ensures a low impedance path for earth faults, but it also means all metalwork connected to the earth bar can become "live" when there is an open neutral outside the house, the voltage level depending on the load on in the house, whether the neutral fault point is just for that house or a group of houses, and how good a connection the earth rod is making to earth, typically not great in most cases.

That`s where the importance of bonding comes in, so at least everything is at equal potential, which reduces shock risk.

Thanks for that - blimey that all sounds so technical! - I once thought about becoming an electrician once, but now after reading that I am glad I never went for it!! lol - I dont think i would ever be able to understand it all!

hufpc8w3adnk65

RCD's must now be fitted too bathroom lighting circuits lads? Or did I pick that up wrong?

Bruthal

MrMac84 wrote: »

RCD's must now be fitted too bathroom lighting circuits lads? Or did I pick that up wrong?

Yes its in a while now. A person is more likely to be injured from falling in a dark bathroom now than the practically zero risk of electric shock from non RCD protected bathroom lights.

hufpc8w3adnk65

Bruthal wrote: »

Yes its in a while now. A person is more likely to be injured from falling in a dark bathroom now than the practically zero risk of electric shock from non RCD protected bathroom lights.

I hadn't heard this. How is it proposed too be done? A seperate 30mA rcd protecting 1 10A mcb and then supplying the entire bathroom from this or put a 10a mcb on the normal socket rcd then feed the bathroom?

Bruthal

MrMac84 wrote: »

I hadn't heard this. How is it proposed too be done? A seperate 30mA rcd protecting 1 10A mcb and then supplying the entire bathroom from this or put a 10a mcb on the normal socket rcd then feed the bathroom?

10 amp rcbo would be the setup. Definitely would`t want to go near socket RCD anyway. A dedicated rcbo minimises nuisance trips anyway.

Andy From Sligo

MrMac84 wrote: »

RCD's must now be fitted too bathroom lighting circuits lads? Or did I pick that up wrong?

and so it should be, thats the way it should be - lots of moisture in the bathroom after a bath/shower

Bruthal

Andy From Sligo wrote: »

and so it should be, thats the way it should be - lots of moisture in the bathroom after a bath/shower

How many electric shocks have you received from the lights, while taking a shower?

tomdempsey200

there's very little hazard from ceiling lights

damaged striplights can be a hazard

hufpc8w3adnk65

So if you were installing a bathroom heater it would need too go on a different mcb too the 10amp rcbo. I'm assuming ceiling fans will be on this new 10amp rcbo?

tomdempsey200

MrMac84 wrote: »

So if you were installing a bathroom heater it would need too go on a different mcb too the 10amp rcbo. I'm assuming ceiling fans will be on this new 10amp rcbo?

heaters wouldn't be on the lighting circuit


ive always wired fans with the light so i put them on bathroom rcbo

tomdempsey200

i imagine we will eventually follow the UKs lead and have 30mA protection on buried and concealed cables for domestic installs

it seems inevitable

Andy From Sligo

Bruthal wrote: »

How many electric shocks have you received from the lights, while taking a shower?

not so much that but if moisture/condensation got into the fitting you'd want it to trip - I think it would trip a RCD but would it trip an MCB? I doubt it, I could be wrong though

Andy From Sligo

we have no RCBO's in our box - Just MCB's and one RCD - I suppose that was the requirements in 2002 when the house was built. We have one of those yokes in the box that only allows one 9kw shower to be used at once as well. Got 2 9Kw showers in the house but cant use both at the same time. - Have a Bell transformer in one slot. When we put on a MCB called 'range socket' (even though we havent got a range!) something buzzes/hum's like a transformer. I thought it was the bell transformer that was buzzing in the CU but its not that.

here's a pick of my consumer unit - just in case anyone is interested lol :-)

Them Bottle fuses (the one for the main fuse in the pic) look so outdated now!

2011

Andy From Sligo wrote: »

we have no RCBO's in our box

In that case do have some form of over current protection for your shower?
This is normally achieved with an MCB or fuse. RCDs unlike RCBOs do not provide over current protection.

Over current scenarios occur in ways:
1) Overload
2) Short circuit

It is very important (and a regulation) that all mains voltage cabling is protected from over current conditions.

tomdempsey200

there's a rcbo on top row of board

for some reason many were C type at the time?

maybe the B type wasn't available at the time.. I can't recall now