house electrics question

96terrano · 12-01-2013, 00:25

I'm curious to why all radiators, matal sinks etc are earthed In my house, and they aren't connected to a 240/250v supply

Why is this

wildbri · 12-01-2013, 00:41

the earth wires are fitted to all metal surfaces so that that they are all bonded together as one. should an electrical equipment become faulty so that the metal surfaces could become live then the bonding to earth will cause a fuse to blow or a circuit breaker to trip so disconnecting the faulty fitting or cable from the mains. to put it simply TO STOP YOU GETTING ELECTRICUTED. regards bri

96terrano · 12-01-2013, 00:55

Ahh right...... I see now, cheers

I was just curious as I thought the sinks radiation system wad isolated form any electrical systems within in house

rustic · 12-01-2013, 08:17

You will also find earth bonds between the hot and cold water taps on sinks and basins etc. but on older systems this was not done.
This is just in case that the hot water system becomes live say through an immersion heater fault and bad earth, thus giving 240 on one tap, and earth on the other.
Since most of us operate both taps at once... This could be lethal.

What really concerns me regarding plumbing, is that more and more people are using plastic pipes, and if used for modifications, could in fact insulate certain parts of the water system, thus loosing safety earths.

So think about safety when using plastic.

Your main earth in houses used to be either the metal water pipe or metal gas pipe, but since these are now often plastic, then the earth might come from the armoured cable near to the meter, or to an earth rod outside the building.

Never disconnect earths

Certainly RCD's or earth leakage trips help to prevent electrocution, however the lighting system is often not protected via RCD's so you are more at risk.
So treat with respect if working with lights especially in bathrooms and kitchens.
There are now a lot of legal issues regarding the extension and additional wiring added to domestic systems.
So seek advice before considering messing with wiring.

I have seen complete idiots replace wall sockets and light switches, and crossed over live and neutral, so it could have been worse, if they got the earth wrong.

This is made worse by the likes of Aldi and Lidl type places selling cheap metal clad switches and sockets, which the general public attempt to swap themselves.

If they get the earth wire wrong, and remember the lighting circuit may not have RCD protection, then this could leave the metal switch plate live.

Rant over for now...

Best regards,

Rustic

davenclaire · 12-01-2013, 10:02

also you msin central heating pump is 240v as are your syncro motors if they go short and they can then the central heating pipes will go live to, bang big time if you touch a radiator. just recently had to rebond all my pipes and fit a new ground earth

rustic · 12-01-2013, 10:14

Quote:

Originally Posted by davenclaire

also you msin central heating pump is 240v as are your syncro motors if they go short and they can then the central heating pipes will go live to, bang big time if you touch a radiator. just recently had to rebond all my pipes and fit a new ground earth

We are talking 4 mm2 cable too, not cheap and nasty flex.

Banshee · 12-01-2013, 20:30

Am I right in thinking they are called "Extraneous Bonds", I remember when our's fell off our shower pipes and my brother was complaining that he was getting an electric shock from the plug hole, we laughed at him thinking he was making it up but when we checked it when the shower was on, we were getting an 11v reading from the plug hole!!!! lol

Fitted a new bond and bingo, no reading

solarman216 · 12-01-2013, 20:45

Quote:

Originally Posted by rustic

You will also find earth bonds between the hot and cold water taps on sinks and basins etc. but on older systems this was not done.
This is just in case that the hot water system becomes live say through an immersion heater fault and bad earth, thus giving 240 on one tap, and earth on the other.
Since most of us operate both taps at once... This could be lethal.

What really concerns me regarding plumbing, is that more and more people are using plastic pipes, and if used for modifications, could in fact insulate certain parts of the water system, thus loosing safety earths.

So think about safety when using plastic.

Your main earth in houses used to be either the metal water pipe or metal gas pipe, but since these are now often plastic, then the earth might come from the armoured cable near to the meter, or to an earth rod outside the building.

Never disconnect earths

Certainly RCD's or earth leakage trips help to prevent electrocution, however the lighting system is often not protected via RCD's so you are more at risk.
So treat with respect if working with lights especially in bathrooms and kitchens.
There are now a lot of legal issues regarding the extension and additional wiring added to domestic systems.
So seek advice before considering messing with wiring.

I have seen complete idiots replace wall sockets and light switches, and crossed over live and neutral, so it could have been worse, if they got the earth wrong.

This is made worse by the likes of Aldi and Lidl type places selling cheap metal clad switches and sockets, which the general public attempt to swap themselves.

If they get the earth wire wrong, and remember the lighting circuit may not have RCD protection, then this could leave the metal switch plate live.

Rant over for now...

Best regards,

Rustic

Well said mate specially about the introduction of plastic pipe for repairs, a little understood area, Rick

rustic · 12-01-2013, 21:17

Quote:

Originally Posted by solarman216

Well said mate specially about the introduction of plastic pipe for repairs, a little understood area, Rick

I would like to thank 96 Terrano for starting his thread,

as I hope it will make people more aware of the issues of messing with electricity, and more especially in areas that involve water.

geoffdown · 12-01-2013, 22:21

but with plastic pipe the water inside will still make the circuit wont it

i hate using plastic pipe in water surply and central heating a will always use copper pipe and solder it hate using the compression joints

jims-terrano · 12-01-2013, 22:27

So with the introduction of plastic water pipes should there be an earth ring around the house to connect to all radiators and taps?

As far as I'm aware plastic is never used for gas lines.

I do know that the regulations that were brought in a few years ago require that the gas lines are bonded right up to the meter.

solarman216 · 12-01-2013, 22:41

Quote:

Originally Posted by geoffdown

but with plastic pipe the water inside will still make the circuit wont it

i hate using plastic pipe in water surply and central heating a will always use copper pipe and solder it hate using the compression joints

no not good enough, the inside of a metal pipe will have a degree of debris on it so insulating the water from the pipe, and even if it was in good contact the resistance is high enough that a shock could result, I quoit an example, shower rise and fall unit screwed to the wall, problem was screw hit a cable and penetrated the live conductor this made the whole shower rise and fall unit live at 240 v, fortunately no one was hurt as it was discovered early, and most today employ plastic stand off's which reduce the risk (this one was all metal) but you can see the problem, Rick

solarman216 · 12-01-2013, 22:43

Quote:

Originally Posted by jims-terrano

As far as I'm aware plastic is never used for gas lines.

plastic for gas is only allowed below ground, Rick

jims-terrano · 12-01-2013, 22:53

Quote:

Originally Posted by solarman216

plastic for gas is only allowed below ground, Rick

Yes very true, I mean't the Hep2o grey or white pipes running water around the house.

Interesting that whilst we are on the subject of electrical safety the regs actually state "a competant person" as far as the fitter and tester is concerned. I guess competancy is someones opinion and is rather vague.

96terrano · 12-01-2013, 23:00

Quote:

Originally Posted by rustic

I would like to thank 96 Terrano for starting his thread,

as I hope it will make people more aware of the issues of messing with electricity, and more especially in areas that involve water.

It was just curiosity

thought id ask here as I've seen good answers on electrical questions before...I'm not displeased with the responses

12-01-2013, 00:25	#1
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	house electrics question I'm curious to why all radiators, matal sinks etc are earthed In my house, and they aren't connected to a 240/250v supply Why is this

12-01-2013, 08:17	#4
rustic Senior Member Join Date: Feb 2007 Location: Staffordshire Vehicle: Maverick Mk I 2.7 TD LWB Posts: 7,825	You will also find earth bonds between the hot and cold water taps on sinks and basins etc. but on older systems this was not done. This is just in case that the hot water system becomes live say through an immersion heater fault and bad earth, thus giving 240 on one tap, and earth on the other. Since most of us operate both taps at once... This could be lethal. What really concerns me regarding plumbing, is that more and more people are using plastic pipes, and if used for modifications, could in fact insulate certain parts of the water system, thus loosing safety earths. So think about safety when using plastic. Your main earth in houses used to be either the metal water pipe or metal gas pipe, but since these are now often plastic, then the earth might come from the armoured cable near to the meter, or to an earth rod outside the building. Never disconnect earths Certainly RCD's or earth leakage trips help to prevent electrocution, however the lighting system is often not protected via RCD's so you are more at risk. So treat with respect if working with lights especially in bathrooms and kitchens. There are now a lot of legal issues regarding the extension and additional wiring added to domestic systems. So seek advice before considering messing with wiring. I have seen complete idiots replace wall sockets and light switches, and crossed over live and neutral, so it could have been worse, if they got the earth wrong. This is made worse by the likes of Aldi and Lidl type places selling cheap metal clad switches and sockets, which the general public attempt to swap themselves. If they get the earth wire wrong, and remember the lighting circuit may not have RCD protection, then this could leave the metal switch plate live. Rant over for now... Best regards, Rustic __________________ Ford Maverick GLX 1995 2.7TD LWB in illusion silver, 98k miles. Owned since new, for 22 years. Best car I have ever owned. Just wish I could drive it more.

12-01-2013, 00:41	#2
wildbri Senior Member Join Date: Feb 2007 Location: south lakeland Vehicle: terrano 1997 tdi Posts: 940	the earth wires are fitted to all metal surfaces so that that they are all bonded together as one. should an electrical equipment become faulty so that the metal surfaces could become live then the bonding to earth will cause a fuse to blow or a circuit breaker to trip so disconnecting the faulty fitting or cable from the mains. to put it simply TO STOP YOU GETTING ELECTRICUTED. regards bri

12-01-2013, 00:55	#3
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	Ahh right...... I see now, cheers I was just curious as I thought the sinks radiation system wad isolated form any electrical systems within in house

12-01-2013, 10:02	#5
davenclaire Senior Member Join Date: Dec 2010 Location: south east Vehicle: terrano 2 lwb Posts: 816	also you msin central heating pump is 240v as are your syncro motors if they go short and they can then the central heating pipes will go live to, bang big time if you touch a radiator. just recently had to rebond all my pipes and fit a new ground earth

12-01-2013, 20:30	#7
Banshee Moderator Join Date: Jul 2012 Location: West Midlands Vehicle: 04 2.7 SWB Terrano II Van Posts: 13,526	Am I right in thinking they are called "Extraneous Bonds", I remember when our's fell off our shower pipes and my brother was complaining that he was getting an electric shock from the plug hole, we laughed at him thinking he was making it up but when we checked it when the shower was on, we were getting an 11v reading from the plug hole!!!! lol Fitted a new bond and bingo, no reading

12-01-2013, 22:21	#10
geoffdown Senior Member Join Date: Aug 2010 Location: devon Vehicle: terrano 2.7tdi SE+ (X)reg Posts: 1,674	but with plastic pipe the water inside will still make the circuit wont it i hate using plastic pipe in water surply and central heating a will always use copper pipe and solder it hate using the compression joints

12-01-2013, 22:27	#11
jims-terrano Senior Member Join Date: Sep 2004 Location: UK Posts: 12,965	So with the introduction of plastic water pipes should there be an earth ring around the house to connect to all radiators and taps? As far as I'm aware plastic is never used for gas lines. I do know that the regulations that were brought in a few years ago require that the gas lines are bonded right up to the meter.